Rob 97 Z28

iTrader: (3)

i have an Edelbrock 600 or 670 (can't remember) on my '88. When driving the car at like 60% throttle or more i've noticed the engine has a back fire through the driverside primary barrell. I messed with the fuel enrichment and the timing alittle but still can't seem to fix it. I have a Holley in my garage(from when the car was a carb'ed L03 car) i was thinking about swapping to see if it fixed the problem. Anybody have any generic tips or pointers for me for this hiccup???


Thanks!

five7kid

iTrader: (14)

About the only reasons I can think that you'd get backfire through one venturi only are: a leaking intake valve on that side of the intake manifold (assume you have a dual plane intake); or a blocked fuel passage (main or accelerator) on that side of the carb.

The Holley would "fix" the latter, but not the former.

Rob 97 Z28

iTrader: (3)

Thanks Five7kid!

The only concern i have with the holley is that im not sure what size it is. I know the edelbrock is etheir the 600 or the 670 but the "original" holley is still in question. I just don't wanna lean it to far out if i use that holley...

five7kid

iTrader: (14)

I don't know why a Holley would lean it out, but the "LIST" number stamped on the front of the choke tower is what will tell you what size it is.

Rayzor32

iTrader: (1)

I like what five7 said about the intake valve i would look there. what kind of eldebrock is it the 1406? do both sides squirt

Rob 97 Z28

iTrader: (3)

Its an old holley (w/old holley logo) but the No.s are as follows:

80457-1
3537

Thats exactly whats stamped on the choke tower

As far as the edelbrock, I believe its etheir a 1406 or 1408...Both primary barrells have jets squirting fuel one on each side...


Please forgive my lack of carb knowledge. True carb knowledge seems to be a lost art



Thanks again for all and any help!!

Rayzor32

iTrader: (1)

where id probably look is first to check that my timing is correct. I then might try the holley to see if the carb is the problem. Then i might look at re-adjusting the valves and doing a compression/leakdown test.

Rob 97 Z28

iTrader: (3)

The timing is a funky issue. Ever since I first tried to set the initial timing its always read 18*-24* advanced. If I try to set it at like 8*-10* it will not run. When my friend and I regasketed the engine and did the cam/timing set and valve springs we both double checked to make sure the timing marks were lined up properly. It had a serious back fire issue when i drove the car from FL to SC but i can't see the engine having jumped timing, just from it back firing especially with it have a brand new Lunati timing set.

The distributor in it now is a hand me down(as is the edelbrock intake and carb on it now) from another buddy, out of another 80's f-car. The only other reason i can see having timing issues is because its a lower compression engine and i run 89 in it. The gas in it now also has some octane boost in it as well. I used to run octane boost in it with L03 just to give it alittle extra "umph".

Its been suggested to me to just junk the HEI i got now and get a brand new ZZ4 HEI and buy a reman'd Edelbrock 750 cfm and try that...Ugh I wish I woulda just kept the L03, put a new timing set, LT1 cam and springs in it and called it good


the holley that i have to test out looks exactly like this one

http://store.summitracing.com/partde...5&autoview=sku

five7kid

iTrader: (14)

http://www.holley.com/data/TechServi...%20Listing.pdf

That's a 600 CFM vacuum secondary. It won't be too big.

Rob 97 Z28

iTrader: (3)

Five7kid,


Again thanks for the heads up on the carb. I'll have to tap 2 of the bolt holes on my intake to make the holley mount properly (they were stripped out) and pick up a new holley,Quad-J style gasket and give it a shot.