[pontiac474ci blown?]

Hi guys,

Can i use a tunnelram with this setup?

-474ci pontiac
-Edelbrock 87cc heads (out of box).
-Harland/sharp roller rockers.
-Ohio crank 4.250".
-Eagle 6.800"rods.
-C&P pistons......10.25:1 comp.
-Crane hydrolic roller cam, .050@ int duration : 230 degr..............exh duration:238 degr.
-MSD ign part#8528.



*Pontiac GTO 1972 , TH-400...........3.08 rear gear.


Thanks,

Eddy

[S10 Racer]

I don't see why not. Is it a single carb or dual carb tunnelram?
What size carb(s) were you planning on?

[y112]

You left a few unanswered questions and these answers can help you receive better info from these educated gear heads.

What is the final actual compression with the 87 cc heads?

What is your tire diameter?

-How is your pride and joy going to be used 90% of the time?

-Are you going to use carbs or EFI?

Here are some things I can tell you.
-Most tunnel rams START working at 4000 rpm.
-About the time your T-ram starts making power, you will run out of camshaft.
-The camshaft you have now won't start working until you reach 45 mph IF you have a tire that is taller than 27". Now your impressive cubic inch naturally "band-aides" some mismatches, but why build wasted HP? You are in the enviable position of owning an impressive combination,
try checking with CAM HELP (comp cams) to insure the best combo.
I seriously think a rear gear change is necessary to effectively use a T-ram.

I'd like to see pictures of the end result!

[pontiac474ci blown?]

Thanks a lot guys for the technical support!!

-My machine-shop says it has now a 10.25:1 compression.
Thats the only compression i know.
-I have 295/50R15 BF Goodrich Tires on the rear.
-I want it for street/strip use.....75/25 percent.
-i am gonna use carbs.

y112: i am think your right..........it gonna out of camshaft!
But there are also street-tunnelram's.......when they start to work?(rpm's)

But I think i have to change it , and also my rear-gear.

Shure i will send the end result on picture!

Thanks,

eddy

[NEW INTERIORS]

I ran a 350 Chevy with 11.00:1,The key is not to over do it with the carbs.I was using two 600 Holley's.Had to much carbs.Went with two 450's fix the problems.You also have to get the right cam.The tunnel rams are usually good at 2500 to 4500,But some are different.hope this helps you .

[y112]

Dude,
I haven't found a tunnel-ram in Holley or Edelbrock, BUT
check out Edelbrock's P-65 dual quad set-up. The part number is #5450. It works at idle to 5500 rpm and works with the Edelbrock Performer RPM heads. You could use your cam and gear ratio, but that cam might not work real good with a stock converter. go to www.edelbrock.com and have a look. I also agree with not going big on the carbs, and Edelbrock recommends #'s 1404, 1405, 1803,1804 and 1805 that range from 500 - 650 cfm.

Get in contact with their tech department and see what they recommend.
Looking better already!!!

[NEW INTERIORS]

Just remember that 650 times two is 1300 cfm.Most engine run very good around 750 cfm's.so the 450's will put you at 900 cfm's. I have never had any luck right off Idle with a tunnel ram,And less you have a nice stall.

[AmericanPackMule]

If it fits use it ~ Performance increese? a little; @ 4,000 ~ 8,000 R.P.M.( Unless you are going from 1, 4 bbl, Carb to 2, 4 bbl Carbs.) But it is an attension getter!

[lg1969]

You guys are still questioning if Tunnel Ram can run on the streets. I can tell you this YES.
I have a 69 Chevelle ever since my mother bought it brand new. I have own the Chevelle for 38 years and still enjoy driving it all over the Island.
Out of the 38 years of use, I had my Tunnel Ram setup for 25 years.
It is seating on a 10.5 :1 compression 355cid with 2.02 heads, Crain fireball Cam, 1.6 roller rockers, with gear drive. The carbs I am using are modified Holley 390CFM. They converted from single feed to dual feed setup with metering block for my secondary from a 780CFM Holley. They are mounted sideways on a Edelbrock Street Tunnel Ram.
The jets are 57 for primaries and 62 for the secondaries, and 6.5 power valve.
I use a blue pump cam on number 2 setting.
With this setup I even passed emission test before the law was change to safety inspection.
Now I got a 11:1 400cid SBC with AFR heads, Comp cam 270H the same 1.6 roller rockers and yes, gear drive. My 355 had so much low end torque, I can pull tree stumps. And now with the 400 I can pull a house. : ) The Chevelle pulls so hard you will need a neck brace. Top end it will make your hair stand. The 400 is coupled to a 350 Turbo Hydro with 3000 stall converter with a shift kit, and a 12 bolts 4:10 gears for the rear end. As you can see, my Tunnel Ram Setup does work with no problem. Install the tunnel ran and enjoy the Fun.

[Nite Life]

I have a Larry Wenzler TR intake on my Formula. It seems to do fine. I have dual 600 Hollys and it does run rich, but spark plugs are cheap.

[TechGuy]

With a tight torque converter and a 3.08 rear gear I would not run a Tunnel Ram. The engine isn't going to accelerate as well as it would with a dual plenum intake manifold. You might be able to get a low profile dual quad to work with your combination, but with the gearing and (assuming) stock converter it wouldn't be recommended.

[WDCreech]

pontiac474,

As far as I know, there is only a couple of t-ram manifolds available for the Pontiac engine. The original Wenzler t-ram can still be ordered from Wenzler. http://www.wenzlerengineering.com/ I think that this manifold would have too large of runners for street use, but the old Warrior, if you can find one, I think, would work good on the street, or you copuld get a single carb Victor, either for a square bore or for a Dominator.

[Nite Life]

here is a wenzler

[PatM]

The old "standard" formula for carb flow, assuming 100% efficiency, would indicate a requirement for about 825 CFM at 6000 RPM. But, assuming you idle at about 750, you're going to be pulling about double the airflow at idle that an otherwise stock 350, idling at 500RPM, might. So, where a 350 might need 4000 to get something from the TR, your displacement (assuming, again, similar port length and volume) you'd need considerably less. On the other hand, there's little doubt that your cam would like a higher-than-stock stall converter. Particularly loading the motor up as you will with the 3.08s. So, Yeah, I think two 450s along with a 3000 RPM stall converter should do OK.

Pat

[AmericanPackMule]

My buddy is building a 350 S.B. Chev. ~ Ford & Chev.? Were are on real good terms...
Chev is My Second Choice. I Can't Change Now! Too Many Spare, Ford Parts.