If i have swapped my EFI for a carb, should the ignition timing be set the same, or should it be advanced/retarded. Either way, what is/should the proper timing be? Currently I am at 6deg BTDC. The engine is a 305 on an 89 IROC

 

Are you leaving the timing under control of the ECM?
If so, leave it be.

If not (you've gone to an MSD, or stock HEI), then no. You'll need to dial it in until you get it right. 10* MIGHT be a starting point.

 

how to leave a ECM timing control ?

 

yes i have gone to an HEI.. dumped the ecm

 

It sounds like (from your other thread) you're just having major fueling issues and want to dump the TBI (know the feeling! But I persisted and fixed it finally going to Rbob's EBL).

Anyhow, if you want to dump the TBI and go carb so be it.
It sounds like you aren't really having timing issues, and that you know how to alter your PROM to what you want.

If you leave the ECM in place, you won't have to buy the adapter to control your transmission (700R4 right?).

TRY just dropping a calibrated carb on it, leave the IAC unplugged, obviously the injector plugs dont hook to anything. If you can, fabricate something to let you hook the TPS up to the carb. That will give you better kickdown control.

Then you can keep your distributor, and leave the timing under ECM control.

You'll probably have to go over the PROM to make the ECM not look at the IAC (since it won't be able to control your idle, you'll keep setting error codes). Ditto on having it not look at your O2 since you have no fueling control.



I might have overlooked something, but that's a start for you.
(oh yeah - you can just ship me your TBI unit after you get your carb. I'll cover the postage. )