Tunnel Ram 383

[matthon]

Here goes nothing!
I got a 68 383 block that was rebuilt with new bearings, 9:1 pistons, bored .030.

I got 452 heads, a tunnel ram, two 600 Holley carbs, Accel distributor, and misc other parts.

I still need a bunch of parts, including timing chain, cam, lifters, pushrods, rockers, and an oil pick-up.

The goal is to pull the stock 383 and replace it with this engine, which I won't be so concerned about blowing up, although I do want this engine to run well.

I considered different heads, including the original ones on the car now, and decided on the 452s because they will work with unleaded gas without extra work/cost, they are in good shape and were at a good price.

I am not sure if they will work well with the rest of the combination, but I am told they should.

So, I have a few issues to sort out:
1) What cam/lifters/pushrods would work best?
2) I'm going to pull the valves out to check them out and put in new seals, can I use the stock springs, or should I get different springs?
3) Is a stock timing chain a good selection?
4) What rockers should I use?
5) This is a 4 speed car, and the crank is not drilled for the input shaft. Taking the crank out to bring it to a machine shop and have it drilled out is not ideal for me, nor is bringing the entire engine to a shop. Can this be drilled out at home, using a jig of some kind and/or a drill press, or should this be left to a machine shop? (I will not be cutting the input shaft!)

I'm not a complete idiot when it comes to engines, I'm just not experienced in the selection of parts to make a combo work well.

I will be getting a new clutch and headers once the engine is sorted.

I need some direction and input to get this done- Help me FABO!

 

[rumblefish360]

Here goes nothing!
I got a 68 383 block that was rebuilt with new bearings, 9:1 pistons, bored .030.

I got 452 heads, a tunnel ram, two 600 Holley carbs, Accel distributor, and misc other parts.

I still need a bunch of parts, including timing chain, cam, lifters, pushrods, rockers, and an oil pick-up.

The goal is to pull the stock 383 and replace it with this engine, which I won't be so concerned about blowing up, although I do want this engine to run well.

I considered different heads, including the original ones on the car now, and decided on the 452s because they will work with unleaded gas without extra work/cost, they are in good shape and were at a good price.

The first issue I see here is the more than likely lack of compresion in the engine. Perhaps, a set of closed chambered heads would help this. Maybe milling what you have?

I am not sure if they will work well with the rest of the combination, but I am told they should.

So, I have a few issues to sort out:
1) What cam/lifters/pushrods would work best?

What is the goal of the engine? Total streetabilty or street strip, race only? The choice of cam duration will be narrowed down to what RPM you plan on driving in.

2) I'm going to pull the valves out to check them out and put in new seals, can I use the stock springs, or should I get different springs?

The new cam should be matched with the new springs recomended by the cam manufacturer.

3) Is a stock timing chain a good selection?

Nothing beats a new timing chain. Double roller.

4) What rockers should I use?

Stockers are OK for a stockish build. Aftermarket units like Pro Mags from Comp Cams or Hugesengines are a inexpensive but a quality part and wise choice.

5) This is a 4 speed car, and the crank is not drilled for the input shaft. Taking the crank out to bring it to a machine shop and have it drilled out is not ideal for me, nor is bringing the entire engine to a shop. Can this be drilled out at home, using a jig of some kind and/or a drill press, or should this be left to a machine shop? (I will not be cutting the input shaft!)

Disasemble the engine and bring the crank in for work.

I'm not a complete idiot when it comes to engines, I'm just not experienced in the selection of parts to make a combo work well.

Most every performance part sold has a RPM range that it works in. (Not timing chains and valve seals) so from there, you can narrow down your selection to workable parts for a basic, but probably not well balanced combonation of parts.

Missing info besides the intent of the car is gear ratio, tire size, wanted engine output etc...

 

[matthon]

This will be a street car, with a possible trip to the strip to see what it will do.
Bottom line is I like to drive this thing as much as possible.

It has a 3.23 Sure Grip.
Tires are 245/60/R14, (fronts are 215/70/R14 if it matters).

The heads on the car now are 915s, which I understand are closed chamber.
I can certainly use those if the 452s would not make sense.

I understand what a cam does and the concept, (lift, duration, etc), yet I know I am not educated enough to make a good choice here.

So do open chamber heads give a higher compression ratio, aka lack of compression, and a lower number is required for a tunnel ram?

Is a well balanced combination possible with the tunnel ram?

I read a lot of comments on running a tunnel ram, most people frown on them but they have never run one, and those that have say it just takes a little more attention to tuning the carbs to get it right.

I have been reading as much info as I can find, but I cannot locate info on the crank issue. If I disassemble the engine and bring the crank to a machine shop, can I just reassemble it using the same bearings?

Is this 4 speed crank issues something a machine shop should know about, and know how to correct?
I guess I’ll find out.

 

[340 8BBL]

well here is some input for you from a guy that runs a t-ram.it can be done with some tuning.your carbs are a little big imo for optimum street use.id like to see 500 cfm afb/edelbrocks or 390 cfm holleys.youll need a good ignition with an adjustable mech advance so you can run a good amount of initial timing.compression could use to be a little higher as well.as far as cams go i like custom grinds,but i look for somthing that works in the 2000-6000 rpm range.if being "driven as much as possible" is one of your goals i choose a cam with a wider lsa like 112 to widen the powerband and retain some idle quality.

 

[zanderzone]

Go for it...
I am doing the same thing at the moment, but mine is stroked to 496.

 

[ProStreetDuster]

If your going to run Holley Vacuum secondaries make sure you buy the Duel Vacuum diaphragm kit so the secondaries are connected and will open at the same time. http://www.summitracing.com/parts/HLY-20-73/
Also get two spring kits so you can adjust how fast they open.
http://www.summitracing.com/parts/HLY-20-13/

 

[rumblefish360]

This will be a street car, with a possible trip to the strip to see what it will do.
Bottom line is I like to drive this thing as much as possible.

It has a 3.23 Sure Grip.
Tires are 245/60/R14, (fronts are 215/70/R14 if it matters).

Whew! OK. Good to know. Small tire car.

The heads on the car now are 915s, which I understand are closed chamber.
I can certainly use those if the 452s would not make sense. So do open chamber heads give a higher compression ratio, aka lack of compression, and a lower number is required for a tunnel ram?

Open chambers lower the C-ratio and a lower ratio equals lower performance. (Most of the time, not a gospel thing, but a combonation thing)
Between the heads, run the one that allows you the highest pump gas runable octane possible.

I understand what a cam does and the concept, (lift, duration, etc), yet I know I am not educated enough to make a good choice here.

I'm having a problem figuring that one out as well. I'm not just sure where to go with this one. Your gear ratio is numericly low, though the small tire helps a bit. Your compresion ratio is still unknown. State of head performance. Etc....

Is a well balanced combination possible with the tunnel ram?

Absoultely!

I read a lot of comments on running a tunnel ram, most people frown on them but they have never run one, and those that have say it just takes a little more attention to tuning the carbs to get it right.

The reason behind that is, the T-rams added expense. Starting with (As purchased new) the intake manifold itself followed by the carb, X's2 and then the added linkage expense, air cleaner expense and any other custom work.

Then the performance aspect of the T-ram. Often a single 4bbl. will make more power and go faster than a T-ram. WHY!?!?! The answer is simple for the most part. Combonation. Not just the engine itself, but what the engine is in. A T-ram shines best up top in the RPM range for starters. Works best in a drag car rather than a car like we drive converted for the strip.
In a heavy car, like we drive, the lack of torque and air speed at low driving RPM doesn't make great torque. A single 4bbl. on a good intake works better. On the street, T-rams are mostly just for show. Now I'm not saying they can not or should not be run on the street nor am I saying they can not be a visous system.

I have been reading as much info as I can find, but I cannot locate info on the crank issue. If I disassemble the engine and bring the crank to a machine shop, can I just reassemble it using the same bearings?

Has the engine been run before?
IF yes, then your answer is no.
IF the engine has not been run before, then your answer is yes, re-use the bearings.

Is this 4 speed crank issues something a machine shop should know about, and know how to correct?

Absoultely. When you bring a crank to the machine shop and tell them it is a automatic crank and you need the poilt hole drilled for your tranny, they'll ask you a few more questions and fix it right up.

I guess I’ll find out.

And find out a few more things as time goes on. This is a learning process that make take a few more dollor than you realize. Engine work is not cheap and sometimes re-ding the whole thing is just a huge pain in the *** that is required.

Having been there and done that like yourself now with a small block, the whole process took half a summer to get strightened out before I was on the road. While it was a total engine rebuilding and redesigning, it was worth it's time and effort when the go pedal was finallly mashed to the floor.

 

[matthon]

If your going to run Holley Vacuum secondaries make sure you buy the Duel Vacuum diaphragm kit so the secondaries are connected and will open at the same time. http://www.summitracing.com/parts/HLY-20-73/
Also get two spring kits so you can adjust how fast they open.
http://www.summitracing.com/parts/HLY-20-13/

I had read about the diaphragm kit, but I also read that since the Weiand tunnel ram has the space connecting the front and rear part of the manifold it is not needed.
I'm not saying it will not need the kit, just the reasoning some have for not needing it.

Thank you for the info.

 

[matthon]

Well, the car has a running engine in it now, so I can take my time figuring this out.

I have read up on calculating the compression ratio, but I am not sure I am knowledgeable enough to get it right.

So, the closed chamber heads will give me a lower comp ratio, which will allow me to run pump gas, and the open chamber heads will give me a higher comp ratio and might cause issues with pump gas- I think I got that right.

My guess is I need to figure the compression ratio out for the 915s to select the correct cam to use?

The engine has never been run, so one more thing solved.

The engine in the car now- I have no idea what the cam is or what the pistons are- I was told the heads were rebuilt and they do look damn clean. It has a high rise single 4 barrel Weiand on it, which is what was there when I got it.
Would it be beneficial to put the tunnel ram on the running engine to see how it runs?
I am going on the assumption that the compression ration would be the same on the old and new engine if I use the old heads on the new engine, and that the cam in the old engine is an aftermarket cam- is there a way to tell?

Just trying to think 'outside the box' so to speak- if there is no value to this idea then that is ok too, a gasket set and an afternoon is not a big deal.

I am thinking that the .030 bore must affect the comp ratio, and I have no idea if the old motor was bored.

I have a Lunati 60303 cam that came with the new engine, I wonder if this would work well with the tunnel ram?

Product Description
Hydraulic. The most awesome 268 cam ever produced! Out-powers all others! This High Performance street cam likes 2400 RPM stall, 800 cfm carb, dual plane intake and headers. Makes un-equaled power to 6200 RPM with proper valve springs. Very strong cam with great street manners.

•Advertised Duration (Int/Exh): 268/276
•Duration @ .050 (Int/Exh): 226/234
•Gross Valve Lift (Int/Exh): .494/.513
•LSA/ICL: 110/106
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 1800-6200

 

[duster340]

[ame="http://www.youtube.com/watch?v=w3wkol6_7XY&feature=feedu"]YouTube - Rat Rod Engine Dyno Testing - Zoomies![/ame]

tunnelrams makes plenty of power even on mild engines ;)
however i think two 600holleys may be a bit big on such a mild 383. a friend uses two 500cfm edelbrocks on his hardrunning 383chevy and that was on edelbrocks recomendation he would have bought bigger carbs if it would have made a diference. its streetdriven and is nothing like what everyone told him it would be to drive on the street the thing can idle for weeks if needed and starts on the twist of the key hot or cold and idles directly dont even need to tuch the throtle. however this is with alitle more compression and more cam.

 

[moper]

For what you have I'd say it's a huge mismatch.. If you want the wow factor, get a small cam and run it. But it won't be fast. It will be very easy to overcam it and it will feel sluggish at part throttle with the rpms those gears will keep the engine in. I'd say do everything you can to get the compression up to a true 10:1. BTW, if the engine was rebuilt with "9.0:1 pistons" and the engine wasn't blueprinted, it's probably closer to 8:1 than 9:1. So there's a lot of room to improve that. On the carb syncing package. Get it. The vacuum the carbs use has nothing to do with the intake vacuum which is what the plenum shares between the front and rear sets of runners. I think a set of 390s would be a much bettter choice, along with a cam like the XE262H. No bigger than that.

 

[RustyRatRod]

Horse feathers! It will run great if you match the parts accordingly. Overcamming is however, the LAST thing you need to do, so be conservative there. Also, as most everyone has pointed out, you should have more compression. If you wanna retain the ability to run pump gas, 9.5 or so is the limit. It can be done well on that compression.....9.1 is a little low...and yes that extra half point or so can make a big difference. The biggest thing I recommend would be progressive throttle linkage......ESPECIALLY if you intend on running the 600s. Progressive linkage would be a big help there. best advice other than all that I got is, listen to people who RUN ONE. Old 340 8BBL knows what he's talkin about. His is a good combo. It can be done, because if puttin a tunnel ram on sumthin was the way to make one run "sluggish" or "not fast", how many of them sumbitches do you think would sell? Yeah. Not many. I've run several tunnel rams in the past and they ran great.....but that was twenty plus years ago so my experience don't count. Listen to those who run them now and follow their advice.....even if it's different than mine cause times change and better stuff comes out. You can do it and make it fly.

 

[340 8BBL]

the lunati cam should work well.and you already have it.i run more cam then what you got in a small block and there is nothing sluggish about it.however the compression is higher and the carbs small (390).

 

[forphorty]

Yep, I'm with Strokerscamp on this one. The old "only good for high rpm" story about TRs is a myth. The Weiand that the OP has is a great intake, Better hang on to it. They don't make them for the B motors anymore, just the RBs. http://www.hotrod.com/techarticles/hrdp_0801_mopar_intake_manifolds/mopar_performance_manifold.html

 

[JoeDust451]

Yep, I'm with Strokerscamp on this one. The old "only good for high rpm" story about TRs is a myth. The Weiand that the OP has is a great intake, Better hang on to it. They don't make them for the B motors anymore, just the RBs. http://www.hotrod.com/techarticles/hrdp_0801_mopar_intake_manifolds/mopar_performance_manifold.html

I 2nd. this, i would have said something earlier but didn't want to ruffle anyones panties :yawinkle:, I do however feel a pair of 500 would work better on his combo.

 

[moper]

Horse feathers! It will run great if you match the parts accordingly. Overcamming is however, the LAST thing you need to do, so be conservative there. Also, as most everyone has pointed out, you should have more compression. If you wanna retain the ability to run pump gas, 9.5 or so is the limit. It can be done well on that compression.....9.1 is a little low...and yes that extra half point or so can make a big difference. The biggest thing I recommend would be progressive throttle linkage......ESPECIALLY if you intend on running the 600s. Progressive linkage would be a big help there. best advice other than all that I got is, listen to people who RUN ONE. Old 340 8BBL knows what he's talkin about. His is a good combo. It can be done, because if puttin a tunnel ram on sumthin was the way to make one run "sluggish" or "not fast", how many of them sumbitches do you think would sell? Yeah. Not many. I've run several tunnel rams in the past and they ran great.....but that was twenty plus years ago so my experience don't count. Listen to those who run them now and follow their advice.....even if it's different than mine cause times change and better stuff comes out. You can do it and make it fly.

We disagree. In terms of tunnel rams, I don't think anything new tech wise has come out unless you're talking about sheet metal intakes. There's more understanding of the physics that makes them work, but nothing in terms of major advances. And those details about why they work just give more solid reasons why not running one on an engine not built for it makes sense. Don't you wonder why they don't make them any more?...lol.
I've run T-rams too. IMO, they are the coolest looking and best shaped intake to have when you don't have a concern about a hood or weather, and when the rest of the combo can support it. In this case, it can barely, so you'll have to compromise to make it work. Like the suggested progressive linkage so the bigger carbs can be run. It's like trying to avoid buying a smaller steak by attempting to use a propane torch to cook the overhanging end because the habachi(sp?) isnt big enough.
The wow factor will be there. But I've watched plenty of cars that have "wow" get pushed into car trailers at shows or struggle to spin the tires in the water at the track before popping and sputtering to a 15+ 1/4 mile.
I would suggest you contact DJV on this board. If memory serves he had a mild 318 with one that was street driven everywhere. I think his current (360) engine uses it too. It took some time and finagling to get it as good as it got before he went to the 360 and then EFI. He might have some good ideas on your setup.
I'm sure it will run. But we each have our own definitions of what running acceptably well is. I was much younger and ignorant when I ran mine and made mistakes. It had too much carb, not enough compression, not enough cam, and not enough gear to make it work as it should have. It ran "well". Now-a-days I could setup a factory 4bbl to outrun it. In fact, at the time, getting outrun with it was a fairly regular occurrance...lol. Making mistakes is how we learn...lol.

 

[RustyRatRod]

Then we just disagree. We can do that, right? Tunnel rams can be tuned very well and beat a single carb every time if you know how to do it. That's all I'm sayin. ...and you don't think carburetor technology has evolved? Ok.

 

[greenhornet]

It's seems these T-ram threads always go in the same direction.. I'm just curious about something, How did the factory long ram engines perform? The runners are a lot longer then a T-ram plus they were in heavyass mopars.. I guess maybe high compression and a solid cam? I dunnno I've never researched the long ram set up's..

 

[duster340]

just to add,i ran a tunnelram and it ran great even overcarbed,would probably have worked alot better with less carb,but there realy is no blackmagic to it they are basic and works as long as you dont put a tunnelram with way big carbs on a lowcompression shortblock with way to much cam,thats what gave them the bad reputation they still have. and i would NOT run the carbs on progresive linkage, 1:1 is the way to go,just picture what happens to the fuel mixture when #7&#8 has to draw the mixture from the primarys on the front carb about 12" forward in the plenum. look at the tunnelram as a I.R system with a plenum added to help these to be honest crappy carbs out with lessending the pulses that Holleys and Edelbrocks realy cant handle,they are designed to work with a steady flow.

 

[moper]

It's seems these T-ram threads always go in the same direction.. I'm just curious about something, How did the factory long ram engines perform? The runners are a lot longer then a T-ram plus they were in heavyass mopars.. I guess maybe high compression and a solid cam? I dunnno I've never researched the long ram set up's..

The long rams are tuned on a different set of pressure waves. There are eight harmonics or waves in the intake tract on a V8. Each one has a unique runner length that corresponds with it's frequency, and the push the harmonic provides to the air/fuel mixture is what the long rams were designed to take advantage of. The lower the harmonic, the longer the runner length needed, and the stronger the torque is at low rpm. Long rams made huge torque with great response with moderate compression and small carbs, but the length of the runner limited horsepower and rpm potential. That's why some long rams were made shorter, and some were modified to remove the divider and shortern the effective lengths. Tunnel rams are intended to make use of the higher frequency harmonics that give a wider power curve and higher rpm potential at the expense of lower rpm performance. Which is why higher dynamic compression and rpms are generally considered required. It's all about design intent and performance window. In racing, the more firing cylinders per minute of run time, the more power gets to the tires. That's where the tunnel rams work well. They move a lot of air, which also makes them great for longer strokes.

 

[greenhornet]

The long rams are tuned on a different set of pressure waves. There are eight harmonics or waves in the intake tract on a V8. Each one has a unique runner length that corresponds with it's frequency, and the push the harmonic provides to the air/fuel mixture is what the long rams were designed to take advantage of. The lower the harmonic, the longer the runner length needed, and the stronger the torque is at low rpm. Long rams made huge torque with great response with moderate compression and small carbs, but the length of the runner limited horsepower and rpm potential. That's why some long rams were made shorter, and some were modified to remove the divider and shortern the effective lengths. Tunnel rams are intended to make use of the higher frequency harmonics that give a wider power curve and higher rpm potential at the expense of lower rpm performance. Which is why higher dynamic compression and rpms are generally considered required. It's all about design intent and performance window. In racing, the more firing cylinders per minute of run time, the more power gets to the tires. That's where the tunnel rams work well. They move a lot of air, which also makes them great for longer strokes.

Damn dude you are smart.... When I need engine advise can I just contact you??? Just looking at the long rams I would have guessed the torque would have sucked..

 

[340 8BBL]

We disagree. In terms of tunnel rams, I don't think anything new tech wise has come out unless you're talking about sheet metal intakes. There's more understanding of the physics that makes them work, but nothing in terms of major advances. And those details about why they work just give more solid reasons why not running one on an engine not built for it makes sense. Don't you wonder why they don't make them any more?...lol.
I've run T-rams too. IMO, they are the coolest looking and best shaped intake to have when you don't have a concern about a hood or weather, and when the rest of the combo can support it. In this case, it can barely, so you'll have to compromise to make it work. Like the suggested progressive linkage so the bigger carbs can be run. It's like trying to avoid buying a smaller steak by attempting to use a propane torch to cook the overhanging end because the habachi(sp?) isnt big enough.
The wow factor will be there. But I've watched plenty of cars that have "wow" get pushed into car trailers at shows or struggle to spin the tires in the water at the track before popping and sputtering to a 15+ 1/4 mile.
I would suggest you contact DJV on this board. If memory serves he had a mild 318 with one that was street driven everywhere. I think his current (360) engine uses it too. It took some time and finagling to get it as good as it got before he went to the 360 and then EFI. He might have some good ideas on your setup.
I'm sure it will run. But we each have our own definitions of what running acceptably well is. I was much younger and ignorant when I ran mine and made mistakes. It had too much carb, not enough compression, not enough cam, and not enough gear to make it work as it should have. It ran "well". Now-a-days I could setup a factory 4bbl to outrun it. In fact, at the time, getting outrun with it was a fairly regular occurrance...lol. Making mistakes is how we learn...lol.

dave,which manifold did you have and what engine was it on?as we both know not all t-ram are created equal.i run an almost identical set up to what DJVCUDA was running.using the eddy street t-ram.i also have the sbm weiand which i tried which is very different in construction than the eddy.it ran ok,but not what i would call "well".the eddy teamed with a set of 500 cfm afbs and a 280/290 cam on a 108 lsa pulled pretty hard with no huge loss of low end,but the narrow center line of the cam gave it a "less user friendly attitude" than what i wanted .i swapped it for a 284 on a 112lsa and a set of 390 holleys.i would drive it anywhere now.its no slouch either.my word on here may not be "law" like yours lol,but there are a few on here who have seen my set up or rode with me.they can attest to the fact that my word is good.i wish i could have run it on a dyno with the single 4bbl,and then the t-ram.id have liked to have seen what the torque/hp curves looked like .

 

[moper]

Non of that info is mine. It's stuff I've learned...lol. It's also the basis for a program to size headers, ports, and intakes to specific rpm points and engine sizes. The program is Pipemax and a brilliant (and really nice) guy named Larry Meaux wrote it. The theories have been around since the flat head was hot rodded.
My words are my opinions. Certainly not law...lol. All in all I stand corrected fairly often, and I learn something every day...lol. No one should be afraid to comment on anything. I'm a firm believer in we wouldnt be typing if we didn't want to help. Even if our experiences and knowledge differs.
340 - I had a Wiend with two 660s on it...lol. On a 340 with a true 9.1:1 and a "284" MP cam. The results were... less than I wanted. So it wasn't there long and honestly, I haven't run one since. Not through any fault of the tunnel ram. The mismatch was my ignorance. I think the Edelbrocks (from what I've seen) are true street tunnel rams. The ports are smaller, the plenums are smaller, and they seem to be for more "mixed duty" applications. Kind of like the STR series with the replacable lids. Take the Edelbrock tunnel ram and smash it flat, and it is the STR series in terms of runner size and length although the plenum are is bigger on the STR. The Offy, Weiand, and Holley t-rams are race manifolds that we put on street cars. With the right support parts, they work well. Without it, not so much. I watched and commented on Dave's work when he was doing it and I think over all he got it very good. The question of "would a single 4bbl do better" was never a question he asked himself. He was committed to making it work well (sounds like you were/are too). IMO that attitude goes a long way to making a tunnel ram's setup, tuning process, and enjoyable service life "more user friendly".

 

[JoeDust451]

Moper, the 660s were the problem on such a mild engine, what made you pick carbs like that LOL.

 

[matthon]

These tunnel ram threads remind me of the political threads, lol!

I appreciate the input, good or bad, so thank you everyone.

Compression: if I need more- what is everyone using to make this determination?
Will using the pistons it has, (from what I am told '9:1'), and the 915 heads, (not using the 452s), solve this issue?
If not, how can I raise it?

Cam: if I raise the compression, should I get a cam with a larger duration number?

The carbs were cheap, so if they are too much it won't be the end of the world to swap them out for smaller ones.

I could just put together what I have and see what happens.

As long as I can drive this thing and run pump gas, I can make adjustments like others have when attempting this ridiculousness, lol!

The experiment continues...