Thread: 350 with 900 CFM of carb questions.

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Hello I have a stock 350 as of now but am going to bolt on a Edelbrock pro ram II tunnel ram with 2 Holley 4bbLl 450cfm carbs.

Now I know thats a lot of carb for a stock 350. Whats the least I can do to make it swallow that much fuel. Can I down size the jets? can I increase spark to make it burn more complete. More cam? how would you approach this if it wasn't ment to go down a track, and was just for fun around town on the weekends? As for what car or truck I'm putting it in yet I dunno, I love 67-72 chevys and GMC's. Thanks Guys...

Well, jetting has to do with air/fuel mixture. If you decrease jets you dont stop the airflow, you limit the fuel. This means you are running lean and that makes for a hot and destroyed engine. You can try to cam it up a bit, but I am not really understanding why you have the desire to put a tunnel ram and dual carbs on a stock engine? Your doing an exotic induction system on a turd? Get a set of good heads, a nice hydraulic roller cam, make a 355 or bigger and actually use that induction system. Otherwise all I can see you doing is making a huge mistake just to make it look like a it may be a performance engine. Sounds a bit like a not well thought out plan. Sorry man, its just my opinion.

Check this equation:

Tunnel Ram + Stock Motor = Untunable Stone

Honestly, you're looking at a tuning nightmare. I had a friend who did this. The only way he got it to work was to disable the secondaries of both carbs, and use a progressive linkages on both primaries. The primaries on the first carb acted as primaries. The primaries on the second carb acted as the secondaries. Essentially, he turned it into a dual-quad-looking four barrel. It was still hard to run because of the huge volume in the plenum.

yeah, what they said. If your going to run a tunnel system on a motor, it would seem more cost effective to have a motor capable of working with the system. With the 350 you have, bolt on a set of heads, an ignition and a good carb. If you still want forced induction, you may want to think supercharging or turbo. With a good intake, you can get the HP you need and still have a Hp look. but a tunnel ram, not a good idea.

Well this is exactly my question, don't tell me I can't do it please tell how to do it. So would a set of after market heads make all the difference? is this the only step I need to take? this is my question, whats the least I can do to make it run right? thanks


Mike

Afermarket heads? Nope.

Heads, cam, high stall converter, right compression ratio, good high-voltage distributor. Then you've got a chance.

Something that has been repeated time and again on this board. An engine is a system - not just a collection of parts. Put 'em all together, and you've got a motor. Screw up one of them, and you've got a door stop.

You can do anything you want, but stand by for the "told ya so."

What compression ratio is ideal, can I get new dome top pistons pressed on to acheieve this? I'm willing to do what I need to do to make it right. I'm here to learn and read, and read, and read. thanks for the help as I do really appreciate all of your guys help.


Mike...

This is a young mans dream motor !!!1000 hp, high valve over lap ,and 3 foot flames outa the carburetors!!!!! all to use the tunnel ram ,which is only suited for high revving engines and will not be very fun at all on the street!!

This is the same engine after it was taken to old man duttweiler (big engine builder)and he did a de tune on it .This pic shows an honest 720 rwhp motor which still took massive tuning and weekly maintenence to drive on the street!!

If ur just tryin to look cool u could put 2 2 barrels on it and fill about half of the volume of both stacks with jb weld and u might not have to rev to 5000 to do a burnout!!!and idle at 2 grand to keep the plugs from foulin!!These fellers and gals here are just tryin to save ya some head aches and let u know what they found out when they did the same thing ur askin!like what was said before an engine is a function of all its components .The componet u speak of is used for high revs and high horsepower drag race type applications.To use this tunnel ram u must get all the components u need to match the specs on ur part.Ok ur part is a 3500 rpm to 10 000 rpm item u need a cam to support this rpm range and u also need all new parts for the rest of the engine to support this rpm range.And finally when u put together this 15000 dollar engine and hope u got it all right and infact it does fire up then u spend a month replacin all the other parts that this monster engine has broken ,bent and twisted .U will come to realize all the warnings that were gave to u were correct .This will be a nightmare on the street not to mention the gas bill!!!!! Or u can look on the bright side u will be an exspert on tunning and engines because u will be under the hood as much as ur behind the wheel.Because 1 of the worst things u can do is to build a race motor then lope it and bog it around on the streets .Not tryin to discourage u but from the question u ask it seems like this would not be a good motor fer u to build.jmo

Back in the early seventies (when premium 100 octane gas was 36 cents per gallon) I ran a big cube, big block, two 650 cfm, t-ram intake, 12.5 compression, .680 lift cam. All this was in an old English Ford Anglia.

This car was a lot of fun on the street. All that power and very little weight made for some mighty impressive evenings with the guys.

THOSE DAYS ARE GONE FOREVER!!

The car took constant maintainance, s-plugs every week. Idled at a different rpm, every day the barometric pressure changed. And you had to be carefull if it was a bit cool out side, as she would shoot flames about three or four ft above the car if you tipped the throttle on a cold engine. Blow the power valves. Then rebuild the carbs!. Fun, but now I'm older and wiser??

What you want to do is not do-able and have any reasonably running engine. First you have a low compression, mild engine that cannot use the plenum volume. An intake designed to work at rpms above where your motors max rpm are. Two carbs where one that size would would be plenty for that stock type engine.

If you could get it running= poor idle(if any). poor mileage. No power. No driveability. BUT it shure looks cool! Leave it parked out front.

So you have an intake plenum full of fuel/air and you open the throttle a bit, while you are cruising with that stock drivetrain and rear gear ratio. BANG! Just like a blower explosion in the old days.

Well this is exactly my question, don't tell me I can't do it please tell how to do it.

gyva,

A how-to-do-it list on on something that appears to be totally impractical is just too much like homework.

Not dumping on you man, just offering a bit of info.