383 Build - Help!

[matthon]

I just moved, so I don't know anyone in the area that can help me with their brainpower. Any help is greatly appreciated.

I have assebled engines before, never a Mopar. Admittedly I am out of my element when it comes to determining what I have and what my options are.

Here is what I have:
1) 383 with new pistons, rings, bearings, cam bearings too - no idea what the pistons are
2) 915 heads, appear to be in very good condition, possibly new springs/valves, looks like they have the larger exhaust valves
3) Tunnel ram with 2 brand new 390 carbs
4) Schumacher headers
5) Water pump, oil pan, dist, valve covers, balancer, pulleys, fan, alt, fuel pump
6) 383 4 speed car with 3:23 Sure Grip, 14 inch Cragars, dual exhaust

I need:
1) Cam and lifters
2) Rocker assembly
3) Oil pump/pickup/rod
4) Head bolts
5) Clutch/pressure plate/flywheel

I've done alot of research, on a clutch, head gaskets, etc, I spoke to Comp Cams and the guy was very helpful, but since I am not sure what I have exactly, he could not recommend a cam- etc etc.

I am not sure what the pistons are. The only markings I can find are on the inside, it looks like 040.

I did not put the engine together, the plan was to check the torque on the rod and cap bolts. I would need to drill the crank for the input shaft.

Low budget, of course, and I really want to use the tunnel ram. It is on the stock 383, which is coming out.

I attached pics below- any info on how to make this work would be huge.
I realize some may say I am an idiot for this or that, and I would agree! That's why I am asking for help. I have gathered this stuff over many years for various reasons and began to think I could put something together with a little more effort.

 

[66fs]

Make sure your pistons are below deck. With the closed chambers on 915 heads they may hit the heads. Early HIPO 383 pistons had a positive deck height.

 

[Abodybomber]

Looks like Silvolite/Keith Black hyperutectic pistons.Check the KB website for compression ratings.I would pop the valve check the valveseats,and for pocketporting.That should give you the info needed for a cam choice.

 

[bOb shingler]

Looks like Silvolite/Keith Black hyperutectic pistons.Check the KB website for compression ratings.I would pop the valve check the valveseats,and for pocketporting.That should give you the info needed for a cam choice.

i agree with this. those pistons should give you some pretty healthy compression being about .020" below deck, but measure it. looks like you'll have about 12.5-1 compression. i'd say use a good felpro headgasket and you'll still need to use premium gas. i'd look into a cam like the mopar 484 since you using those restrictive shoemaker hearders.

 

[JohnRR]

Make sure your pistons are below deck. With the closed chambers on 915 heads they may hit the heads. Early HIPO 383 pistons had a positive deck height.

INCORRECT , there was not a 383 built with positive deck height, NHRA spec gives a positive deck height and NHRA spec doesn't come close to actual factory specs ... except for cam lift...


The pistons look like KB 162's , they should be .024 below the deck in the block has not been decked a ton . Ring end gap on the top ring is critical with those pistons .

 

[JohnRR]

i agree with this. those pistons should give you some pretty healthy compression being about .020" below deck, but measure it. looks like you'll have about 12.5-1 compression. i'd say use a good felpro headgasket and you'll still need to use premium gas. i'd look into a gam like the mopar 484 since you using those restrictive shoemaker hearders.

That KB piston won't give hem anything remotely approaching 12.5 compression in a 383 with a stock stroke . the KB400 has a dome and is rated at 10.0 , those look like flat tops , he'll be lucky to have 9.0 , depends on what the chambers on the heads are cut to.

 

[moper]

They are KB162s by the top. They are not proud of the block, looks more like they are about .020 down. The block deck does not look like it was ever cut, so that sounds about right. Like JohnRR says - You might be at 9.4:1 depending on the heads and gasket used.

 

[BBBCUDA]

I'm running .030" flat tops with NO valve reliefs, @ .020" below deck. Heads are milled closed chambers at only 74 CC's, .039" gasket. I just hit 10.0 to 1. The big valve trough, and most likely larger cc heads will kill a bunch of compression.

 

[Salty Dog]

I need:
1) Cam and lifters
2) Rocker assembly
3) Oil pump/pickup/rod
4) Head bolts
5) Clutch/pressure plate/flywheel

I'm going to answer this in reverse;
5. I like a Borg & Beck set up vs. the multi figered units offered by the likes of Centerforce, though, it is a good set up, the pedal feels weird. The Centerforce set up worked well though. You need to remove the over center spring IIRC.

4. MP offers a set inexpensively. ARP/Pioneer's are fine, maybe a tad more expensive.

3. MP again or Mellings, which is what MP has to offer IIRC again. The whole set upp is in the MP catolog. Easy to get in one shot.

2. MP replacement Hyd. rockers are easy to get, but, often not up to par for a performance level engine due to unreliable ratio from rocker to rocker. A basic set of roller rockers can be obtained cheaply from Huges or Comp cams. You'll need to order new pushrods. A P-rod checker is available through both companies. Huges makes it easy. They'll rent you the checker and deuct the rent cost if you get pushrods from them.
IMO, a decent deal!

1. This is very hard to make a recomendation on. The following info may help and yeild a good result or 2 if you can answer them.

With the known 3.23 gear set;

1. what is the intended tire size and what is the intended performance goal, or, what you want the car to do.

2. You wouldn't happen to know the valve sizes and air flow rates of the heads would you?

FWIW, the pair of Holley 390's is a great choice of carbs for there abilty to remain flexable enuff to choose a cam from mild to a good bit of street wild. A total of 780 cfm available for the engine is good with the abilty to handle a decent build up of the engine and cam size.

IDk for sure about cam size and duration splits for this set up and what it is you want, but, as a general shot in the dark, a cam of about 230-236 intake duration would slide in and perform great IMO. It's not so big as to cause problems with PB or drivabilty issues while making good street power and work with the small carbed tunnel ram.

 

[matthon]

OK, dummy alert- this is a little confusing to me, but I know with a little help I can get this right, eventually.

Ring end gap- I really don't know how to address this.
My understanding is the 915 heads are 78.5 CC.
What the chambers on the heads are cut to? I was not aware that this was needed, or frankly what it is. Are we talking about cleaning up the chambers of the heads, or shaving the head surface?

About a year or so ago I bought open chambered heads and I was informed the compression would not be high enough and I should get closed chamber heads. I was going to use the stock 915 heads on the original engine, but I came across these 915s with the bigger exhaust valves supposedly the best you can get.

So where do I need to be with the compression?

I want to drive this thing, as much as I do now, which is alot, but without the tired engine in it now
I want to get it right, and avoid mistakes, but the reality is there is a cost concern, and no one I trust or know well enough around here.

Should I take this thing apart, or start over?
Someone say no, please.

 

[matthon]

Salty Dog- the Borg and Beck?
I have that now, and it is worn I'm sure, but everyone else seems to have no love for them.
What makes you a believer?
I can't make an honest comparison because mine is worn and has been contaminated with oil not to mention the broken clutch fork mount on the bellhousing.

 

[bOb shingler]

That KB piston won't give hem anything remotely approaching 12.5 compression in a 383 with a stock stroke . the KB400 has a dome and is rated at 10.0 , those look like flat tops , he'll be lucky to have 9.0 , depends on what the chambers on the heads are cut to.

yes you may be correct as i was comparing a dome piston but that being said he will still have aleast 10-1 which will still need premium gas. remember he is using a closed chamber head.

 

[Salty Dog]

Salty Dog- the Borg and Beck?
I have that now, and it is worn I'm sure, but everyone else seems to have no love for them.
What makes you a believer?
I can't make an honest comparison because mine is worn and has been contaminated with oil not to mention the broken clutch fork mount on the bellhousing.

What makes you a believer? Well, lets see, it has been used for many many decades before i was born and there still in use today. There is no problem in there operation though I'm not thrilled with pedal effort when the pressure plate is near or at comption levels Depressing the pedal at this level (600 lbs or so) the beefing up of parts (AKA Linkages) becomes a must do.
This is where I like the diaphram pressure plate better,

Danm near 30 years in the biz of playing with ot rods and race cars, I have not had any problem out of the ordinary or really any different than a diaphram unit.

 

[BBBCUDA]

I don't see an over bore stamp on the piston tops, so I will assume it's standard bore. With a .039" gasket, and a .020" below deck, (might be more), the +5 cc valve notches make 9.06 to 1 compression if the heads are indeed 78.5 cc's. Nows the time to cc some stuff before it goes together, in case you want to have some things milled.

 

[CUUDAK]

I don't see an over bore stamp on the piston tops, so I will assume it's standard bore. With a .039" gasket, and a .020" below deck, (might be more), the +5 cc valve notches make 9.06 to 1 compression if the heads are indeed 78.5 cc's. Nows the time to cc some stuff before it goes together, in case you want to have some things milled.

There is a 40 stamped on the bottom of the piston in the pic so I would assume .040 over bore. Everything looks to be balanced due to the drill marks under the pistons. I agree they are below deck. I'm thinking around 8.6:1 with a Felpro Blue.

FYI,
my 400 is 0-deck with notched flat tops and 906 heads @88cc's.
9.0?:1 compression with .060 MLS headgaskets.

Hey matthon,
that low deck is gonna need to spin some rpm's to benefit from that tunnel ram. Your cam choice will need a broad rpm range. I would ditch the ram and put a M1 or RPM intake on it with a quality 4150 style 750. It WILL run better! If you want something to stick out of the hood find you a 8-71 supercharger for it. The compression ratio is ideal I bet.
Be sure to clean that engine thoroughly before assembly. Use some diesel or kerosene with a parts brush then blow it out. That brown preserver needs to be removed. Looks like a decent pump gas street setup. Stay away from the VOODOO cams! Garbage! A lot of the cams offered for Mopars are Chevy grinds. I would stick to the Purpleshafts or move on to a Scott Brown custom ground cam. Your choice though! Depends on your pocketbook. Looks like the heads have double springs so I would stick with a cam below .500 lift. Honestly I would choose a cam, lifter and spring kit to be safe.

N/A you should be good for 375-400 horses with the right cam and induction.
Just my 2 cents.

 

[CUUDAK]

Sorry! Doublepost. Stupid IE9 locked up

 

[bOb shingler]

keep the tunnel ram.

 

[swedefish]

Hey Matt nice to see that you´re working on your Fish.
Here´s a link to KB about the top ring end gap.
http://www.kb-silvolite.com/kb_car/clearance_pop.php
When I buillt the engine for my Fish, I had the block square decked to ensure that the pistons were equally below deck in all four corners.
I use a steel shim head gasket for my 915 heads.
According to my calculations it would give me a 10.2:1 in compression.
I´m running the MP purple 284/484 108 degree cam in the engine, but that wouldn`t be my choice if I would do it allover again. I would probably with a Hughe cam instead.

 

[moper]

Ring end gap- I really don't know how to address this.
Pull them out, remove them carefully fromt he piston using a ring expander, and then mearsure them by placing them in the bore, using the piston to square them up to the deck surface. If they are too tight, buy a ring filer and file fit them. Chances are they were installed too tight because those pistons have unique specs.


My understanding is the 915 heads are 78.5 CC.
What the chambers on the heads are cut to? I was not aware that this was needed, or frankly what it is. Are we talking about cleaning up the chambers of the heads, or shaving the head surface?
I'll bet several cheesburgers they are larger than 78cc. Most factory are closer to 82-83. You mill the heads to verify they are indeed flat, adn to give the gasket a good surface to bite on to. And last, you mill to get the finished chamber volume to what you want for a desired result.


About a year or so ago I bought open chambered heads and I was informed the compression would not be high enough and I should get closed chamber heads. I was going to use the stock 915 heads on the original engine, but I came across these 915s with the bigger exhaust valves supposedly the best you can get.
The factory '67HPs came with 915s with the 1.74 exh valve. A few non HPs also have them, but most came with the smaller valve. least that's what I leanred and has been my experience. But, it's Mopar. You can never say "only" and "never".

So where do I need to be with the compression?
The 383s I build I aim for 9.8-10.2:1, depending on the camshaft. It usually requires decking the block and milling the heads.


I want to get it right, and avoid mistakes, but the reality is there is a cost concern, and no one I trust or know well enough around here.

Should I take this thing apart, or start over?
Someone say no, please.
No. I only say that so you feel better. I would take it apart to check things out. Then you "know".

 

[JohnRR]

Ring end gap- I really don't know how to address this.
Pull them out, remove them carefully fromt he piston using a ring expander, and then mearsure them by placing them in the bore, using the piston to square them up to the deck surface. If they are too tight, buy a ring filer and file fit them. Chances are they were installed too tight because those pistons have unique specs.


My understanding is the 915 heads are 78.5 CC.
What the chambers on the heads are cut to? I was not aware that this was needed, or frankly what it is. Are we talking about cleaning up the chambers of the heads, or shaving the head surface?
I'll bet several cheesburgers they are larger than 78cc. Most factory are closer to 82-83. You mill the heads to verify they are indeed flat, adn to give the gasket a good surface to bite on to. And last, you mill to get the finished chamber volume to what you want for a desired result.


About a year or so ago I bought open chambered heads and I was informed the compression would not be high enough and I should get closed chamber heads. I was going to use the stock 915 heads on the original engine, but I came across these 915s with the bigger exhaust valves supposedly the best you can get.
The factory '67HPs came with 915s with the 1.74 exh valve. A few non HPs also have them, but most came with the smaller valve. least that's what I leanred and has been my experience. But, it's Mopar. You can never say "only" and "never".

So where do I need to be with the compression?
The 383s I build I aim for 9.8-10.2:1, depending on the camshaft. It usually requires decking the block and milling the heads.


I want to get it right, and avoid mistakes, but the reality is there is a cost concern, and no one I trust or know well enough around here.

Should I take this thing apart, or start over?
Someone say no, please.
No. I only say that so you feel better. I would take it apart to check things out. Then you "know".

Spot on .

I'll add that the 915's wit hthe 1.74 exh valve from the factory will have a big H and P stamped on the end of the head with the bolt holes .

78.5 cc is probably the NHRA spec which is always smaller than actual . I have a pr of 915's that measure 82 cc , not sure how much they have been cut already.

 

[matthon]

I did not see an HP on the heads but I could have completely missed it.
Just by looking at the exhaust valves, is it possible to tell?
It does not appear to have any room for a larger valve.

I looked at the heads again and they looked like they have been milled, unless they look that way from the factory.

I have a set of 452 heads that need work but wouldn't that raise the comp too high?

So someone drilled the pistons to balance them, but could have easily not gaped the rings.
They are stamped 040 on the bottom.

I have a 750 Holley that I rebuilt and ran on the car. The thing actually ran better with the t-ram, quieter, more responsive on the highway, and more fun. Not that it has any bearing on this engine. I'd still like to use it though.
It appears the variables that I need to figure out, I have no way of determining most.
The head cc's, if they were milled and to what, the piston height?

I really appreciate everyone's input, but it is a double edged sword so to speak. That's part of the learning process, getting completely confused along the way but to get this right I really need someone local who knows what the heck they are talking about and will also not screw me over.

This thread is not over until I am doing burnouts, and sooner than later.

 

[BBBCUDA]

If you don't mind, letting us know about where you are located might snag you a member who can help you out. A cheap plastic burette, marked in CC's is about all thats needed to CC a set of heads. I've seen closed chamber heads checked that were well into the mid 80's for CC's. It wouldn't be hard to check bore size. It could be .040" over, or that could be a casting number on the bottom. I don't recall ever seeing a piston stamped with it's diameter on the bottom, but maybe the KB 383 pistons are? The 460 Ferd ones I just looked at were stamped on the top. I'm not trying to beat you up about the compression, but you might be closer to 8.5 to 1 than you think. It's relatively easy to fix right now.

 

[demon seed]

Quote: I did not see an HP on the heads but I could have completely missed it.
Just by looking at the exhaust valves, is it possible to tell?
It does not appear to have any room for a larger valve.

The 915's you have may have been cast originally with the 1.60" exhaust valve and somewhere down the road someone had 1.74 exhaust valves installed which is normal. Those heads you got have the 1.74 valves and you can tell because there is very little (almost none) head material between the exhaust and intake seats and valves.

The 452 heads you mentioned are open chambered, essentially if you use them you will effectively get a larger volume combustion chamber which will decrease your compression ratio therefore go with the 915"s.

 

[matthon]

I'm not sure where I need to be with compression, or how to get there at the moment.
I am confused somewhere near Albany NY.

 

[womanator]

I don't believe the Schumacher headers will work with a 4-speed transmission they have to be modified.