I know there are a million threads on engine swaps and ive read through many but im getting some confusing answers. some threads state needing certain things and others dont mention things. so here's what i need to know.

i currently have an 86 iroc with the stock 305 with TPI in it. the motor has seen better days and im planning on buying the 290hp/326ftlbs 350 with PN-12499529. I plan on keeping the TPI system and am just wondering what i need to change from stock to make it run. I know I need the injectors, knock sensor and ecm. What I need to know is what else i need. im really wondering if there is any computer work to be done as some threads dont mention any. Any information as to anything else i need and where i can get it would help alot as i hope to order everything i need at once and get this done. thank you for any help you can provide for me.

 

Injectors, and knock sensor and module are all you "need". The 350 ECM doesn't do that much for you. You could probably get by with none of them.

This will give you about a 30 HP jump over the stock LB9.

 

what do you mean by 30hp??...that motor make's 290hp

 

Ah, but how is that "290" measured?

The ratings you see in the year model information (e.g., https://www.thirdgen.org/1986-chevy-camaro ) is "as-installed" - aka, "net" flywheel HP. The engine has to be running the water pump and alternator, and the intake and exhaust have to be attached as they will be in the car. So, the 190 HP is "net".

Crate engines, however, are rated "gross" - in other words, unburdened. No water pump or alternator, long tube headers with open exhaust, carb with a velocity stack no air cleaner. And, they have been known to use one intake/carb combo to come up with the HP rating, and another to get the max torque rating.

It's pretty typical to lose 15-20% going from gross to net. Then, you lose more going from carb (what the 290 HP pull used) to TPI.

So, 220 HP net, compared to your stock 190 HP net, is about what you'll end up with.

 

so from what your saying the stock ecm will be compatable? or is it going to need replaced?

 

The stock ECM will handle it just fine. It's an MAF system, next to nothing depends upon the displacement of the engine. Injector size is just to ensure there is enough fuel at max power, it's not a programming item. They even used the same MAF for the factory 350's (a slight undersize situation) and again the ECM isn't programmed differently between the two displacements for MAF reading.

That doesn't mean the 350 PROM won't perform better. PROM tuning almost always improves performance, regardless which system you start with. The 350 tuning was a little more aggressive, but the factory 350 also had higher compression and better heads, along with roller lifter cam, than the 290 HP crate.

 

thanks for the help. i can live with the stock computer till i figure out if i can get a new comp or get it tuned from my uncle's shop. i just wanted to ensure that it would atleast run when i got everything back together. you really were a big help.