I dropped a 91 350 in my 85 iroc last week and i decided to keep the MAF system stuff instead of changing over to speed density. so im trying to figure out what year 350 chip is compatible with my ecm the service number is 1227165 and the current chip is an amu8958. thanks.

 

BUA is the released chip for that year ('86 actually). This is a Corvette calibration as I don't believe that an L98 was offered in an '85 or '86 f-body.

ABWT is an '87 MY release with an L98 and auto for the f-bodys. There are others that should also work. Someplace along the way the fan relay wiring changed (relay pin change required), then the '89 MY releases have VATs activated.

Note that the injectors that were used is important. If you used the L98 22#/hr injectors, then an L98 calibration should be used. If the 19#/hr LB9 injectors were used, then need to stay with an LB9 (305) calibration.

RBob.

 

i got the 22# injectors on there btw so can i use a 350 chip from say an 87 7165? if thats even possible. because the engine runs good with the 305 chip but its not operating to its full potential cuz it just drives like a suped up 305 instead of a 350 with headers and stuff.

 

I can see that it isn't running that well, with the 350 injectors and 305 calibration it will be rich, mostly at WOT.

The MEMCAL/PROM from an '87 should work. Even one from an '88 MY should work. If the fan isn't correct that is nothing more then moving a terminal/pin is the fan relay connector.

RBob.

 

okay do you know what chip numbers would be from 87?

 

you can see some of the bcc here and get the oem p/n on gearhead efi although most of the memcals are now discontinued.

http://www.chevythunder.com/prom_bcc_1987.htm

http://www.gearhead-efi.com/BCCFind/