tbfirebird

Ok first off i was tbi but went to carb ,i got 1.94int and 1.64 exht valves and a 97 trans am lt1 cam shaft and a spreadbore intake with an adapter for my edelbrock carb.

Okay heres the problem i first noticed black burnt crap on my passanger side on the intake manifold/and its coming from under the edelbrock carb and it sounds like and exhaust leak or some but the gasket should cover the bottom of the carb but it seems like its a leak but i dont know what to do plz help.also it only does that when i floor it.

also i got my base timming with the vaccum advance unplugged at 13 or 14 cant remeber is that i good spot or what/also it seems my stock tbi fuel pump will keep up with the motor sometime then it wont.

ljnowell

A lot of people will tell you different, but I say good call on the edelbrock carb. Sounds to me like you have a vacuum leak under it though. Check all of your lines, and replace the gasket under the carb. Its a cheap part, and if it doesnt fix it, big deal. Are you sure the carb is tightened down all the way? Are you experiencing anything else, like a rough idle, or stalling? Personally with a carb, I opt for the mechanical fuel pumps.

305sbc

iTrader: (3)

Could you be talking about the EGR port on the intake?
It should be blocked off with a metal plate.

See the port at the center (top edge) of this pic?

F-BIRD'88

are we talking about a factory spreadbore intake manifold?

If so you will need to go the GM dealership and get a
spreadbore heat riser plate (stainless steel)
goes under the carb gasket and prevents the exhaust heat passage from burning a slot in the carb gasket.
looks like a Qjet carb base gasket but is made of stainless steel shim.

Any mid 70's to mid 80's chevy that use a Qjet carb used this shield under the carb gasket.

Here is one for a Buick with a Qjet
#372613S Steel Heat-Shield Plate and Gasket for Rochester 4MV Quadrajet 4-bbl carb.
Idem "I" on
This page

tbfirebird

yep the egr was leaking so who sells a plate to blok it off i tried sheet metal and alot of rtv sealent and it still wont stop the leak it keeps pushing out a lil bit of exhuast gas out. also anyone got any tips on wha tthe timming should be .the car also does run hell of alot better with the egr blocked off liek the wa it should be.i notice alil more torque bottom end.

305sbc

iTrader: (3)

The intake should have came with a block-off plate. You could fabricate something from metal or you could just cram it full of hardening epoxy putty under your sheetmetal plate. The key is to give it a day to harden before you put the exhaust heat to it. You probably blew out the RTV before it was hard. Ultra-copper silicone will live through exhaust heat if it has enough time to set-up. The thicker the RTV the longer it needs to harden.

Sounds like you may have excessive backpressure in your exhaust system forcing it to look for leaks.

THEGENERAL

i have made many of these and they arent to hard to make but you need to let it dry as said above when you apply the rtv and try and make it out of the thickest metal you can find around the garage 1/16 -1/8 is awsome

tbfirebird

um i got the stock tail pipe size that came with the tbi motors that might not help.

also i let it dry for 24hrs and its been working kind of jus a lil niddle size leak also when i get a full cat bacl what kind of hp should i get /i got the 2 1/4 i think size tail pipe with the stock cat gutted and a 80 series 2.5inch muffler.

THEGENERAL

all honestly people can make guestimations of how much horse power your gonna have but there is no true way of guessing without a dyno of before and after your install