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FBODS4EVER
05-20-2007, 02:41 PM
well those of you that have heard of me saying im trying to make the meets and all. and trying to get the formula fixed. well its happening. i put a 350 prom in the stock computer which made it run right. but not 100%. it stopped the back firing. the 305 prom wasnt pushing enough fuel. anyway, it was picked up today by my friend with a tow truck. and went to the shop in washington township. my mechanic says that we ought to scrap the tbi and computer. so me being 36. and used to the good old cars agreed to a carb and manifold. so shes in the shop for a fuel set up conversion. and a little exhaust work. im going with a 750 douple pumper. and a rpm air gap aluminum intake. should have it back in a week or 2. i told him no rush. as long as its before june. so hopefully i will then be able to make it to some meets.

The Fixer
05-20-2007, 03:11 PM
IMO, a 750DP is WAY too much carb for a stock L98. Go for a 650 with vacuum secondaries. You'll get better performance and much better mileage! Don't forget you'll also need to remove the stock distributor and get an old-style HEI distributor with vacuum advance. Good luck with it!

NJSPEEDER
05-20-2007, 04:09 PM
why the need to ditch the fuel injection? people have held together 450ish horse motors with TBI using a stock computer with a custom prom, so your set up shoudl be no problem.
by going carb you will be spending a bunch of cash and kissing your gas mileage goodbye.

sounds to me more like jsut another mechanic that doesn't want to deal with it the right way and would rather jsut spend your money on his old parts.

90FormulaWS6
05-20-2007, 04:20 PM
id stick with TBI... make sure you have the right size injectors in there too ;)

maroman88
05-20-2007, 06:26 PM
stick with the TBI...i wish i did, i went the other way and blew all kinds of money on a TPI swap. i learned tons about motors and sensors and wiring by doin it myself tho

BigAls87Z28
05-20-2007, 08:06 PM
If it was economicly feasible...sorta is...but I would take whatever TPI stuff I have left sitting in my garage and put it on the 72 tomorrow. I miss EFI so bad....carbs ftl.

FBODS4EVER
05-20-2007, 09:37 PM
the mechanic (who owns a 70 camaro with a big block :) suggests that the way the car is set up, that it would be way more expensive to have a dyno and custom chip set up for the computer. its not a stock l98. it has been rebuilt. it has ceramic coated hooker headers. all msd vac adv distributor wires and coil. a pretty radical cam. flowmaster exhaust. and a few other goodies. if the carb is too much it could still be jetted down. as for mileage, its not gonna be my daily driver. i have a dakota for that. both my birds are for fun and show. i grew up with the old novas and chevelle's. even a few old trans am's. (the formula is actually the 10th one i owned) i have been out of the hobby for awhile as well. it will also be easier for me to work on. ive had alot of problems with fuel injection. a friend of mine who builds race engines in the 8-10 second range also agrees that i go with a carb for my set up. he says that the tbi is like a 2 barrel carb. and that i would get more power and torque with the carb set up. i always like the tpi setup. i had a few of them. next swap for me after this is a t-56 from a 94-97 trans am. i dont think the t-5 will stand to many dumps on the clutch. i purchased my new items (carb and manifold from 00ls1. gave me a hell of a deal as well. but by the time my car is done. as long as it runs ill be happy. i appreciate all of your opinons. ill post pics. also i may put my tbi set up, up for sale in the classifieds section if anyone's interested. thanks again guys.

Tru2Chevy
05-21-2007, 06:37 PM
What heads and cam are on that motor?

- Justin

NJSPEEDER
05-21-2007, 08:03 PM
from the sounds of it, you don't have anything on the engine that TBI would have any trouble handling with a custom prom. and they only cost around $300-350, that is far less than all the parts and labor you are about to pay for jsut to end up with less drivability and crappy mileage.
mileage may notmeanmuch to you right now, but at $3+ per gallon, when you want to go somewhere and have to dump in gas constantly, you will regret the decision.

JL8Jeff
05-21-2007, 09:04 PM
How are you gonna pass inspection with the carb? Stick with the TBI and get the custom prom. It won't be more than $350 like Tim said. If you do anything, get a Holley Stealth Ram setup for it!

WildBillyT
05-21-2007, 09:38 PM
IMO, a 750DP is WAY too much carb for a stock L98. Go for a 650 with vacuum secondaries. You'll get better performance and much better mileage! Don't forget you'll also need to remove the stock distributor and get an old-style HEI distributor with vacuum advance. Good luck with it!

I agree 100%. A 750 sounds like it will be way too much carb for your engine. A 650 VS will be a better choice and probably faster. Yes, you can detune a 750 to work, but it won't be optimal. Be sure that you match your manifold to your application as well- if your engine runs out of power at 5500 why get a high rise manifold that goes to 6500? You will just be giving up low end power.

What heads and cam are on that motor?

- Justin

Please post this as well...

FBODS4EVER
05-23-2007, 06:30 AM
edelbrock rpm heads are in the works. a rpm matched cam is as well. i spoke with the previous owner. the engine was rebuilt. it has trw pistions and rings. along with a 30 over. the cam? not sure what size. i also have a manual trans. holley dosent recommend using a vacuum secondary carb with a manual. with a automatic yes. as for inspection, as i stated before, it will be for fun. it is going to be registered as a collectible. and for running at the track. a buddy of mine, the one that builds race engines. says with what i have in mind, and what my plans are, i should be pushing over 400 ponies when im done. im not looking for any super computerized car. i just want to build something. something that i know i have. nos and all are coming later.

WildBillyT
05-23-2007, 07:36 AM
edelbrock rpm heads are in the works. a rpm matched cam is as well. i spoke with the previous owner. the engine was rebuilt. it has trw pistions and rings. along with a 30 over. the cam? not sure what size. i also have a manual trans. holley dosent recommend using a vacuum secondary carb with a manual. with a automatic yes. as for inspection, as i stated before, it will be for fun. it is going to be registered as a collectible. and for running at the track. a buddy of mine, the one that builds race engines. says with what i have in mind, and what my plans are, i should be pushing over 400 ponies when im done. im not looking for any super computerized car. i just want to build something. something that i know i have. nos and all are coming later.

Edelbrock cams are known for being archaic in design. You can do better for the same or less money.

holley dosent recommend using a vacuum secondary carb with a manual.

Where did you hear this?

FBODS4EVER
05-23-2007, 10:42 PM
on holley's site. and i called. Quote from holley "

QUESTION: How do I know if a vacuum or mechanical carburetor is best for me?
ANSWER For street cars the vacuum secondary carburetor works best on midweight or heavyweight cars with an automatic transmission. They are more forgiving than a Double Pumper is because they work by sensing engine load. The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes.

WildBillyT
05-23-2007, 11:09 PM
on holley's site. and i called. Quote from holley "

QUESTION: How do I know if a vacuum or mechanical carburetor is best for me?
ANSWER For street cars the vacuum secondary carburetor works best on midweight or heavyweight cars with an automatic transmission. They are more forgiving than a Double Pumper is because they work by sensing engine load. The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes.

Huh. I know plenty of people that do it (usually with 3310s) - but their cars aren't too radical. Did you ask Holley about carb sizing as well? I'm interested in what they say.

V
05-23-2007, 11:15 PM
on holley's site. and i called. Quote from holley "

QUESTION: How do I know if a vacuum or mechanical carburetor is best for me?
ANSWER For street cars the vacuum secondary carburetor works best on midweight or heavyweight cars with an automatic transmission. They are more forgiving than a Double Pumper is because they work by sensing engine load. The mechanical secondary carburetor is best on a lighter car with radical camshaft and a lower gear and manual transmission or on a car that is going to be used for racing purposes.


techically that doesnt say vacuum isnt for manual trans cars. It says for lightweight manual trans race cars, mechanical is better.

Tru2Chevy
05-28-2007, 12:40 AM
Edelbrock cams are known for being archaic in design. You can do better for the same or less money.
:stupid:

Look into the Comp Cams Xtreme Energy line, or the new Lunati Voodoo line. Both will offer so much more than an edelbrock cam will.....

- Justin

FBODS4EVER
05-28-2007, 10:17 AM
hey tru2 how do you like the Comp XE 274?

Tru2Chevy
05-29-2007, 09:31 AM
hey tru2 how do you like the Comp XE 274?

It sounds great....couldn't tell you much more about it because the car still hasn't left the driveway under it's own power.

crazy77c3 had the same cam in a mild 350 (performer intake, edelbrock RPM heads) in his '77 vette, and it ran pretty well once he got the carb close to sorted out.

- Justin