tunnel ram / cam combo lowdeck opinions

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moparwedge

moparwedge

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I have a tunnel ram with 2 holley 670 cfm vac secondary carbs. I have narrowed down to 2 hydraulic cams.

Xtreme energy 230/236 @ .050 - lift 488/491, 1800-6000 rpm, 2200 stall recommended, 110 lobe sep

Thumpr 227/241 @ .050- lift 486/473, 2000-5800 rpm, 2000 stall recommended, 107 lobe sep.

this is a street car 400 cube in Duster.
 
Tunnel rams are generally in the 3000+ starting rpm range.

Opinion? A solid roller.

DJV used a smaller cam on his small block. I bet he could help out with it all.
 
If you want looks, you'd be fine. If you want performance, up the cam size and the stall.
 
For a street car with dual quads, pick the cam that will give you the most vacuum at idle, will give better manners around town, and won't " burp and fart " at a light. can also use Roads lifters to help with vac signal. Only time I use them is with dual quads.
 
moparwedge said:
I have a tunnel ram with 2 holley 670 cfm vac secondary carbs. I have narrowed down to 2 hydraulic cams.

Xtreme energy 230/236 @ .050 - lift 488/491, 1800-6000 rpm, 2200 stall recommended, 110 lobe sep

Thumpr 227/241 @ .050- lift 486/473, 2000-5800 rpm, 2000 stall recommended, 107 lobe sep.

this is a street car 400 cube in Duster.
Click to expand...


Out of your 2 choices, the first one.

IMO Neither cam will run 5800-6000 in a low deck. I also completely disagree with the recomended stall speeds. Way too low. My pickup truck flashes to 1700...

2 440's both built witht he same 242/528/112 cam made peak power at 5600 and 5800 respectively. Same RPM heads, the only difference was the size of the carb.

If you MUST run that tunnel ram pick a cam that works in it's RPM range and has a wide LSA (110 or higher) In regards to lift. There is no reason to open the valve further than where the heads will flow.
 
I would highly recommend a solid cam over a hydraulic. Much better performance and valve train stability.
 
What kind of specs would you guys recommend?
 
Your right! The OP didn't state.

How about a dead stock late 1978-400 (7.8-1 ratio) with a stock no stall converter 727 in a Duster.
Gear, wheel & tire size will be purchased later to suite.
 
My tunnel ram has better 60ft times than the six pack. I had always hear about tunnel rams being peaky but have never experienced it. I don't over carb them though. Ran one on the street in a 400 powered Demon and on my RB powered Duster. You might want to run smaller carbs with that cam combo on a 400. I would stay under 280 duration unless you have spent $$$ on a converter. Do an X or H pipe to help fill in the low end and make sure you have the advance curve set up right.
 
mguner said:
My tunnel ram has better 60ft times than the six pack. I had always hear about tunnel rams being peaky but have never experienced it. I don't over carb them though. Ran one on the street in a 400 powered Demon and on my RB powered Duster. You might want to run smaller carbs with that cam combo on a 400. I would stay under 280 duration unless you have spent $$$ on a converter. Do an X or H pipe to help fill in the low end and make sure you have the advance curve set up right.
Click to expand...

I actually read an article in hot rod magazine wherein they disproved the age old myth that tunnel rams are only useful in high RPM horsepower and kill low end torque. It did make more high RPM power but it also made more low end power. The Tunnel actually made more power across the spectrum and had a wider powerband as well.

I'd be looking at 500cfm carbs. 600 at most.
 
^^^ agreed with the last two post. Op's carb's seem a bit big. I would highly recommend a progressive linkage for street manners. Most nay sayers to dual quad tunnel rams never had one, or to scared to try one because of what they heard. To those I say-- grow some !
 
Although not on your short list, the Mopar .528 solid would scream here. JMO.
 
without engine specs, converter stall, axle ratio. I see the make'ns of a real street pig. imo
528 solid would work well with a 3500 stall and 4.30 gear in a stock 400 with headers.
 
Well on one hand a T ram can be made to work really well on a car like this but on the other hand I've seen a lot of eff'd up tunnel ram installs!

I'd highly recommend starting with a small cam and working your way up the food chain. This is assuming that the OP doesn't have much tuning experience with tunnel rams and/or performance motors. It also really depends on the rest of the combo. Compression ratio, rear end gears, etc. If that is a nice 10:1 engine with zero deck pistons and close chamber heads then it will be a lot easier to make run than a factory stocker with the pistons way down in the hole and low compression open chamber heads. And a set of 4.11 gears out back will make a T ram look like a hero while a set of 2.76 gears will make it a pig.
 
moparwedge: here's what will need to be done to the carbs. purchase the tops for the vacuum pods that tie the signals together. next get 2 vacuum spring kits and use the black springs in each pod. next 2 accelerator pump cam kits and use the green ones. buy the simplest straight throttle rod and make the stock cable bracket taller so it's inline with the carbs throttle levers.
 
RustyRatRod said:
Although not on your short list, the Mopar .528 solid would scream here. JMO.
Click to expand...

fishmens67 said:
without engine specs, converter stall, axle ratio. I see the make'ns of a real street pig. imo
528 solid would work well with a 3500 stall and 4.30 gear in a stock 400 with headers.
Click to expand...

I love this cam. I've used it twice in 2 different BB builds. I can only speak to a 440 but it made peak torque in build one at 3900-4100. Build 2 it made peak torque at 3500.

My current combo runs this cam with a 3500 convertor and TTI headers. It goes 11.70's in full street trim.
 
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