Tunnel Ram on a 383

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FastMopar71

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I'm starting to plan out my next Mopar project and I wanted to see if I could get some insight and opinions. I'm looking for a Demon to build, and since I already have a small block (340) Duster, I was thinking about putting a 383 in a Demon. I have always wanted to building a car with a tunnel ram, so I'm thinking maybe now is the time to do it. I don't know much about tunnel rams, like is one brand better than the next? What kind of build to I need to do in order to support a tunnel ram? I have heard they can be difficult to tune for the street, but I have no idea how true that it. How do I determine what size carbs I need? I'm not looking to building something totally radical, but not leave it stock either. I have a stock '68 383, 727 with 70K miles on it. It was originally a 2 bbl, but is now a stock 4bbl.

What is a good combo to go with for a tunnel ram? Any information or suggestions would be appreciated. Thank you!
 
The tunnel ram will improve your performance no matter how it is set up short of a super charger or turbo. About like bolting on a 50 shot you don't have to refill.
 
OK mguner...that is good to hear! I could also build a small block with a tunnel ram. I have either available to build, but I just though a 383 would be neat and different since most people build 440's when going with a big block.
 
Whatever you do, make sure you send the carbs to someone like Thumperdart on here. He is a sharp dude and can get you set up for 2x4's.

You need to remember that you double the jet area, double the emulsion, double the air bleed and doubt the needle and seat area, among other things, but YOU DON'T DOUBLE THE AIRFLOW.

Never use smaller than 750 double pumpers and what ever else you do SPEND THE MONEY FOR A CUSTOM CAM. The biggest mistake you can make is over cramming a tunnel ram.

If done correctly, a tunnel ram will make more HP, more torque and more fun all over the power curve. Just don't over cam the thing. CUSTOM CAM from a REPUTABLE cam grinder. I use several and have posted them. Once more, in no particular order:

Racer Brown
Cam Motion
Jones Cams
Bullet

There are others but that is wo I get on best. I say go for it.
 
I have always heard and thought that a smaller carb setup like (2) 375 or 500 cfm's would be easier to tune and more streetable, but you are saying no less then (2) 750's?!?!?! Really?? Can you explain why?
 
Actually with your setup small carbs may be a good choice. Certain rules still apply as far as volumetric efficiency and velocity go. I ran a pair of small AFBs and 650 2bbl Holleys and both worked very nicely. Every car I put the tunnel ram on went at least half a second faster.
 
So I think what I might do is get the block bored maybe like 30 over. Use the stock heads, I would get them ported and whatever else they will need to be efficient. Probably use stock rockers, and a cam a couple steps above stock. Probably use the HP manifolds I have rather than spend the money on headers. The manifolds make a rather easy fit in an A-body. I haven't decided if I would stick with the 727 or go with a 4 spd.
 
It is very easy to over cam a 383 and be disappointed. Short duration and high lift is the way to go.
 
Been there done that and seen it many times. What is a mild cam in a 440 can be a bottom end killer in a 383. It is a different story to some degree if you add compression but the shorter stroke likes a bit of help down low. It is still going to wind like crazy because you have good heads. You did say street friendly. Now if you spend bucks on a converter or a 4 speed setup and low gears you can be more aggressive. But I did not interpret your post as being that type of build.
 
So your saying putting a Hi RPM only manifold such as tunnel on almost stock engine with two 750 cfm carbs is going run like adding 50HP Shot of NOS?

"The tunnel ram will improve your performance no matter how it is set up short of a super charger or turbo. About like bolting on a 50 shot you don't have to refill."

Okay well good luck throwing 1500 CFM of carbs at a stock 383 :violent1:
 
So your saying putting a Hi RPM only manifold such as tunnel on almost stock engine with two 750 cfm carbs is going run like adding 50HP Shot of NOS?

"The tunnel ram will improve your performance no matter how it is set up short of a super charger or turbo. About like bolting on a 50 shot you don't have to refill."

Okay well good luck throwing 1500 CFM of carbs at a stock 383 :violent1:

You are very wrong to think a tunnel ram is a high RPM manifold only! It shows full range increases! They also make single 4 tops for said manifolds of which I have several and thank you, yes I have had great luck with them. You are the genius trying to over carb it.

Here is a great read on what mild 383s can do. This setup would also get very close to 400 HP with a properly tuned tunnel ram and have excellent street manners. I ran a single 4 tunnel ram with a TQ on my 71 Demon with the HP cast iron exhaust on a 400 and it was a beast. A stock smaller converter with a 727 and gears anywhere from 3.23 to 4.56 and blew many doors off. Run a good X pipe on your exhaust and that will also give you nice low end gains.

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I'm very interested in this thread. I have a 383 out of a 66 Charger that was rebuilt with 906 heads and an Isky cam and valvetrain and an Edelbrock single 4 intake. Guy I bought it from said cam is an RV type grind and ran good on the street, but he forgot long ago what the cam specs were. It sat for a long time before I got it but turns over freely. So I know it needs to be atleast rebuilt with new gaskets, bearings, etc. I have a Weiand tunnel ram for it and also a much bigger cam.

There was an article in I think Car Craft magazine probably 10 years ago about a 383 with Edelbrock aluminum heads and they dyno'd the engine wth a bunch of different intakes and the Weiand tunnel ram made the best power numbers. Was in the 600 horsepower range and torque was not too shabby either. That was kinda what I was aiming for, sounds like maybe a few others here are also. And I have a Weiand single 4 tunnel ram top that is available if anyone is interested. It's new, never run.
 
Interesting thread ... but I think the trick is going to be FINDING a tunnel ram for the 383 ... I think tunnel rams for the low-deck B motors have been out of production for a long time ... gonna have to work the swap meets and classifieds to find one.
 
Ive got low deck set up on my 67 cuda.(avatar)

Tunnel ram better be willing to put fenderwell 2" headers with open chamber heads.
2- 600 cfm holley. geardrive 150 shot nitrous, 3500 stall ,8 3/4 rear 4.10 suregrip
if you want to pull.
Otherwise stick with small block.
 
Ive got low deck set up on my 67 cuda.(avatar)

Tunnel ram better be willing to put fenderwell 2" headers with open chamber heads.
2- 600 cfm holley. geardrive 150 shot nitrous, 3500 stall ,8 3/4 rear 4.10 suregrip
if you want to pull.
Otherwise stick with small block.

And what cam were you trying to make work with that combo? The manifold was not the problem!
 
Just saying, if you want a big block to run higher than 4500rpm and still produce power.

D
 
I ran a single 4 tunnel ram with a TQ on my 71 Demon with the HP cast iron exhaust on a 400 and it was a beast. A stock smaller converter with a 727 and gears anywhere from 3.23 to 4.56 and blew many doors off. Run a good X pipe on your exhaust and that will also give you nice low end gains.

vbpgimage.php

Hmmmm so I must have been dreaming when I did this.... 383-400 is a different animal. Remember you are using the same heads as the 440 with less cubes. It makes a difference.
 
I'm just glad you found some more guts for your teener! That 400 I ran had a Road Runner cam and 516 heads with the cast manifolds and would wind to the moon! Took on a friends T/A Chally with the 340 Six Pack 4 gear and it wasn't even close. He kept asking how tight I was winding the motor and I had no idea.... No tach!
 
I agree and believe totally.

Big blocks rule, I might be keeping my Dart for that reason alone.
 
Good luck with your Tunnel Ram
There is a reason they have long runners- high rpm 3000 -8000+

Last time I ran one was in 1982 in my F/MP 1966 Chevelle
301 ci 680 lift 290 duration @ 50 roller cam, 14 to 1 compression , hemi 4 speed pro shifted with 6.17 gears -tunnel ram with 2 800 cfm holleys

Have had few race cars since and still do
 
Good luck with your Tunnel Ram
Last time I ran one was in 1982 in my F/MP 1966 Chevelle
301 ci 680 lift 290 duration @ 50 roller cam, 14 to 1 compression , hemi 4 speed pro shifted with 6.17 gears -tunnel ram with 2 800 cfm holleys

F/MP? Wow, I use to love the Modified Production class! John Dianna with his tunnel-rammed small-block Duster that use to reach for the moon every time he launched was my ATF in MP.
 
I know that the 383 tunnel Rams aren't produced anymore, but there are enough out here to be had. I visit Carlisle a few times a year. Hopefully I can find one complete with carbs and all. I am really glad that their is a lot of interest in this post. I want to do as much research as I can to be the combination right. I would hate to put it together and than be disappointed. Now the questions:

Will I be ok with the stock heads and rockers? I will get them ported and have a valve job done on them of course.

How much should I bore it? Or do I even need to?

What about the Pistons and rods? Can I get away with stock and the right cam change?

Would headers make a huge difference over the HP manifolds? I don't want to spend the money for under chassis BB headers if I don't have to.

This is not going to be a strip car by any means. I just want a cool looking street car that has some balls, because let's face it, something sticking out of the hood always looks neat :)
 
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