anyone have a new or aftermarket computer chip (PROM) to allow me to use my stock 1987 CCC Quadrajet with the ZZ4 crate motor? I know that GM offered a conversion kit that contained this chip around 10 years ago, but of course like most useful things they made for our cars it is now discontinued. The main feature of this chip was the elimination of the EGR valve to allow the aluminum or Vortec heads to be used with all other factory wiring. Since I can't afford to pay $250 for a new PROM I'm looking for a used or aftermarket chip for this combination for a reasonable price since I just love the last year Quadrajet! Thanks for the help, Dave

I've used both the stock '86 LG4 PROM and an aftermarket chip I got from JC Whitney back in 1999. Runs the same with either one. I've unplugged the EGR solenoid connector and again it runs the same as with it plugged in.

I don't think you'll have a problem without EGR with a stock PROM.

Ebay. You can still buy that chip from others, assuming they are really selling you what they say they are selling you.

Also- might want to check with the guys over on Montecarloss.com. Quite a few guys over there have used that same chip for various conversions. I've heard chatter of ZZ-4 chips floating around.

Your assessment of the ZZ-4 chip is correct- it's almost exactly the same as the chip used in the L-69 305 HO motors, except the EGR system is turned off.

Before you spend ANY money I'd try to use your current stock chip and see how it runs. Carb computer controls ain't nothin' like EFI systems- they do very little and aren't very smart. The spark advance curve is really the only thing that's much different between them. Many people have deleted their EGR systems completely without the stock ECM knowing any different (then again others have gotten the dreaded "check engine" light after a while). But start with what you've got and see how it goes before you plunk down your hard earned bucks. There will still be used ZZ4 chips out there on the market a couple months from now if you decide you need one.

Thanks for the information. Just worried about the service engine light staying on all of the time if I unplug the EGR wire. I'll try it and see what happens.
Thanks,
Dave

I've had mine unplugged for about 3 months, daily driving and about 30 runs at the track, no SES light to date.

I recently got the 1228079 ECM used in later year Monte Carlo SS cars (and multiple other places). I wanted to make sure my fuel and spark maps were in the ballpark for the beefed up 350 I dropped in. Hypertech offers a chip that works in this computer, specifically for the mid-late 80's Caprice police interceptor cars with a 350, and the E4ME computer controlled quadrajet. I think it was around $100.