Tunnel ram cam?!

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vntned

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So I'm ready to make my dart a little wilder than it is! Currently it's just a 360, with H116CP pistons, (scr is at 9.4:1 with standard felpro head gaskets),
CompCams 268AH-10, untouched small valve 587 heads, 340HP manifolds, Eddy LD340 intake and a 750cfm Street Demon. The car is backed by a 2.66 first gear A833 4spd with a 3.55 in the back and a 26" tire.

Current plans are to keep the short block, change the cam, put on some hogged out big valve Jheads, Offenhauser dual quad tunnel ram, some big gnarly Hedman Husler fender-well headers, and a 3.91SG I just picked up for it.

I've already got the headers, and tunnel ram. The heads are at the machine shop being gone through. Shortblock has around 10k miles, so it's still basically fresh. I've got a fresh 4spd ready for it! And all this stuff is set in stone.

My two questions are cam and carbs. Carbs I'm thinking a pair of 390s or 450s. Im not sure on where to start really. I want the car to remain a weekend brawler with occasional trips to the strip. However, I'd like to run low 12.0s or better.

Suggestions for what cam specs I need?




-Yes, I know I should call Racer Brown
-Yes, a custom cam is better than an off the shelf
-No, I don't care about you hating CompCams
-No, I don't care about how much you love Hughes
-No, I don't care about cold starts with a tunnelram
-No, I don't need a mathematical breakdown of gear vs rpm vs torque multiplication vs etc..
-No, I don't care about anything not regarding cam specs for this specific application

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The carbs you posted are not only too small, they are worthless.

You need a carb that you can tune. If you don’t know how to do it, or don’t want to do it, you need to buy custom prepped carbs so you are close enough at the start to make them work correctly. Two Pro Form 650’s without a choke is probably the best bang for the buck if you want to do it yourself.

Buy a custom cam from anyone you want. But I can promise you there are no good tunnel ram cams “off the shelf”.

The biggest mistakes guys make in TR stuff is the wrong cam and carbs. Cut corners there and you’ll have issues.

Your case is the perfect example of when a fast ramp is needed. If you aren’t comfortable with a fast ramp SFT you should consider a solid roller.

I won’t post specs because you need to get on the phone and TALK to as many cam grinders as you can. Take notes. Write down what they tell you for specs and compare them. You’ll quickly see the outliers on both sides.

I will say this...I’ve never seen an OE architecture TR engine want an LSA over 109. If they call out for an LSA wider than that, they didn’t use enough duration and are trying to crutch upper RPM power by opening up the LSA, which is a sure bottom/mid RPM power killer.

BTW, you didn’t mention what RPM you want to be shifting. That makes a difference.
 
I'd like to keep the max revs at 6000rpm. I know that isn't very high, but I'm not sure I want to run this shortblock much higher than that.
 
Well YR beat me to it... just as I was typing 650 DP and the other carbs being glorified scrap metal. But with a 6000 rpm limit, I wouldn't think about anything that resembles a tunnel ram. But, if your mind is made up and the spring and retainer clearance is okay for the lift, here you go, and good luck!
https://www.summitracing.com/parts/hrs-710461-10/make/dodge
 
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I saw your rant at the bottom of the original post about not caring about others opinions on various things. All I can say is, be prepared to do a lot of tuning & not get the results you are shooting for. Tunnels rams look good on street cars but their day to day performance isn't the best in the west. They are meant for race cars & higher RPM's to utilize the deep plenum area. I've tried what you are starting & finally gave up after 2 years of disappointing results. I don't run a tunnel ram on my bracket car, just a single plane intake & a severely worked 4779 Holley 4 point idle circuit carburetor. With the 408 stroker in it I turning 10's with great results & with the 416 I'm building, my plans are to be in the 9 second range. If you are interested in any further specs, PM me, we'll discuss it.
 
vntned said:
So I'm ready to make my dart a little wilder than it is! Currently it's just a 360, with H116CP pistons, (scr is at 9.4:1 with standard felpro head gaskets),
CompCams 268AH-10, untouched small valve 587 heads, 340HP manifolds, Eddy LD340 intake and a 750cfm Street Demon. The car is backed by a 2.66 first gear A833 4spd with a 3.55 in the back and a 26" tire.

Current plans are to keep the short block, change the cam, put on some hogged out big valve Jheads, Offenhauser dual quad tunnel ram, some big gnarly Hedman Husler fender-well headers, and a 3.91SG I just picked up for it.

I've already got the headers, and tunnel ram. The heads are at the machine shop being gone through. Shortblock has around 10k miles, so it's still basically fresh. I've got a fresh 4spd ready for it! And all this stuff is set in stone.

My two questions are cam and carbs. Carbs I'm thinking a pair of 390s or 450s. Im not sure on where to start really. I want the car to remain a weekend brawler with occasional trips to the strip. However, I'd like to run low 12.0s or better.

Suggestions for what cam specs I need?




-Yes, I know I should call Racer Brown
-Yes, a custom cam is better than an off the shelf
-No, I don't care about you hating CompCams
-No, I don't care about how much you love Hughes
-No, I don't care about cold starts with a tunnelram
-No, I don't need a mathematical breakdown of gear vs rpm vs torque multiplication vs etc..
-No, I don't care about anything not regarding cam specs for this specific application

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with all them I don't cares and I'm doing this no matter what , why come here and ask for opinions ? sort of a waste of your time and the good people here willing to help you build a better more enjoyable car to drive , that is if you intend to drive the car .
That is all , good luck
 
What size tubes are on those headers? Are those the 1-7/8 X 40 set?
 
no porting? stock valves not even 11/32 stems?
so rpm limit fits valve weight cost effective choice
and no flow increase at higher lifts
what rockers? stock will work fine
what size headers?
old school mopar cam from racer, engle, crower, bullet is one way PM dart19666
fat lobe without going gonzo chasing lift, sort of a dwell lobe
listen to yr on the carbs
if this mostly for show and not go then even vac sec and progressive linkage works, even two TQs
think 50 years ago when there were no al heads
many builds just like yours
 
The "don't cares" at the bottom of the original post isn't to hurt any feelings. It's just an attempt at avoiding the same generic responses that aren't actually helpful. I know some people just don't get that.

I understand that the tunnel ram isn't optimal for daily driving. I also understand that I could go as fast or faster with a single plane and one carb. That isn't the point of this build! If I was going for ultimate speed I wouldn't be building this car like this.

I'm trying to capture the look and feel of a ridiculous '60s-'70s street racer. The tunnel ram is gonna happen and I'm keeping the 4spd. I'm just trying to get some advice to make what I have as good as it can be.
 
I can respect that kind of nostalgia build. I also recommend 4.56 gears if you and your cooling system can live with them. Are you still staying at 9.4:1 or are you going to be getting up to 10:1? What octane fuel are you planning on?
 
I'm gonna run the 3.91s for now, but I'd like a set of 4.56s for days at the track.

I'm waiting to get the heads from the machine shop so I can cc them and see what I need to do. I'd like to get the scr close to 10:1, without touching the short block. If I can cut the heads and run thinner head gaskets and achieve 10:1 I'll be happy.
 
I disagree that the TR “needs” anything specific for a cam to run well.

If you got a cam that was suitable for the rest of what your goals are, it will work just fine with a TR.

Offy has had some weird manifold **** through the years........ how about a couple pics looking down into the plenum.
I’d like to see what’s going on with the divider under the carbs.
 
PRH said:
I disagree that the TR “needs” anything specific for a cam to run well.

If you got a cam that was suitable for the rest of what your goals are, it will work just fine with a TR.

Offy has had some weird manifold **** through the years........ how about a couple pics looking down into the plenum.
I’d like to see what’s going on with the divider under the carbs.
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when you say 'offy had some weird manifold ****' do you mean like this currently on ebay uk? Mopar Dodge Chrysler 318/340/360 Tunnel Ram Intake Gasser Rat Rod Drag Horrod | eBay
neil.
 
Demonracer said:
I saw your rant at the bottom of the original post about not caring about others opinions on various things. All I can say is, be prepared to do a lot of tuning & not get the results you are shooting for. Tunnels rams look good on street cars but their day to day performance isn't the best in the west. They are meant for race cars & higher RPM's to utilize the deep plenum area. I've tried what you are starting & finally gave up after 2 years of disappointing results. I don't run a tunnel ram on my bracket car, just a single plane intake & a severely worked 4779 Holley 4 point idle circuit carburetor. With the 408 stroker in it I turning 10's with great results & with the 416 I'm building, my plans are to be in the 9 second range. If you are interested in any further specs, PM me, we'll discuss it.
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I just did a street tunnel ram. The owner says he will NEVER go back to a single 4. What has him excited is the bottom end with the TR.

If you do a TR correctly, and IF you buy a cam just for it, and IF you are willing to tune it, the payoff is gold.

If you don’t want to do that, the TR isn’t for you. The BS about the TR being high RPM is just that. BS.
 
PRH said:
I disagree that the TR “needs” anything specific for a cam to run well.

If you got a cam that was suitable for the rest of what your goals are, it will work just fine with a TR.

Offy has had some weird manifold **** through the years........ how about a couple pics looking down into the plenum.
I’d like to see what’s going on with the divider under the carbs.
Click to expand...


LOL. The cam is the number ONE killer of TR performance. If the cam is correct for a single 4 it damn sure isn’t even close for a TR.
 
yellow rose said:
I just did a street tunnel ram. The owner says he will NEVER go back to a single 4. What has him excited is the bottom end with the TR.

If you do a TR correctly, and IF you buy a cam just for it, and IF you are willing to tune it, the payoff is gold.

If you don’t want to do that, the TR isn’t for you. The BS about the TR being high RPM is just that. BS.
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i've had a few cars with tunnel rams, most were daily drivers. the long runners are what give good torque, the same reason the tpi chevies of the eighties had reasonable torque (for a chevy).
neil.
 
yellow rose said:
LOL. The cam is the number ONE killer of TR performance. If the cam is correct for a single 4 it damn sure isn’t even close for a TR.
Click to expand...

I guess I must just be lucky then..... because when I did the back to back test on the dyno, about a dozen times, the TR always made more power.
And not once was the cam made “specifically” for the TR.

I’ll just keep doing what I’ve been doing.

Most of these “mid-level” TR’s, like what the OP is showing pics of....... actually peak at a lower rpm than the typical “race” style single plane.
 
If you search intake manifold shoot out results, and one of the tested units is some variation of the Offy “360*” split single plane variety...... you’ll see that they normally end up near or at the bottom of the standings.

Sure....... you can try it as is....... but I wouldn’t be expecting anything too wonderful to happen with it in that configuration.
The Weiand TR, which is very similar other than the plenum, has the nice fully open plenum...... and those intakes work very well.

So, if after you get it running...... you’re a bit underwhelmed...... try cutting those dividers out.

Part 1 of Hot Rod's Mopar Intake Manifold Shootout

https://www.hotrod.com/articles/hrdp-0801-mopar-intake-manifolds/

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I was wondering if anyone else had read the same articles about tunnel ram testing. I would have to agree with those results from what I’ve seen in person with the Offy. Every Weiand or Edelbrock TR5 or Street Tunnel Ram (Same intake, different tops) was quicker by a large amount.
 
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I ran a tunnel ram on my 340 and it ran better everywhere over the rpm and 750 holley dp. Carbs were 2 69 340 avs. Engine was mild and ran 2+ tenths faster.
 
If you are considering .525 lift better flow the heads preferably with the tr
you can go backwards on the flow with unported heads
 
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