I putting together an 85 iroc. The motor is a stock 89 camaro tbi long block, the intake is a 86 upper tpi with a 88 lower manifold. The computer and chip are 86 305 ho (I don't remember the #'s. My question is will this combo run right? I have some 1.6 rockers laying on my bench if I install them will it run right without reburning a chip. I not looking for crazy speed i'm building it for my daughter just thought the 1.6's would wake that cam up alittle.

 

It should run OK, the rockers won't affect the ECM. Most important is to use 19# hour injectors that the 305 used.

The engine may tend to ping a bit as the TBI heads are swirl port. They don't require as much spark advance as the TPI heads. Just try it and see how it is.

RBob.

 

thanks, i saw where the lt1 cam swap would not run well without a new tune so i thought i would check im not ready to burn chips yet thanks again!

 

I don't think it will run. As the ecm for the TPI which was probably a 1227165 ecm that used a MAF sensor and I think was the 1099ACXT prom.

You are trying to use a 305 H.O TBI ecm, I am not 100% sure if that used a MAP sensor or MAF.

I think your best bet would be to use a 1227730 ECM with a AUJP prom. you will still have to burn a prom and shut off the VATS for it.

Don't forget to measure out your pushrods when you put them rockers on. They might offset your rockers enough on the tops of your valves to create a problem.

 

The 1.6 rockers won't be too detrimental at all, what makes for a harder O2 correction is the duration of your camshaft, and since the cam is staying stock you will be fine. Your best bet would be to get your hands on an adjustable fuel pressure regulator, as upping the fuel pressure in increments will help compensate for the amount of air you increased, thus making the ECM's job much easier to average 128-BLM. The ECM will still be able to correct even without the adjustable fuel pressure regulator, but when we make it easier for the ECM to do so it will reward you in the overall driving experience with less hiccups...

Just be sure your using a TPI ECM for your TPI setup...

 

Just an update for someone in the future. Finnaly got her running and it runs great in the garage very smothe idle and snappy response. Probably wont road test for awhile ill post results then. Thanks for the imput guys !!!