I inherited an 86 IROC-Z from my Brother-in-law who let it sit in a barn for six years due to a rod knock he couldn’t figure out. Short story: I’m in the Marine Corps and was home on leave just before moving to Japan. I got the IROC running and diagnosed the rod knock right away. My band-aid over the bullet hole fix was to replace the one “bent” rod. After getting it running again, it ran very well, but I want to fix it right the next time I get back to the States. I’m planning on buying a 350 long block from GM (to save time). I’ve researched my question, but have yet to get a definitive answer. My question is, do I need to replace the 305 ECM when I use a 350? The ECM already has aftermarket “supper chip” in it. I’ve read that I need to replace the fuel injectors or the pressure regulator, but nothing about the ECM. Thanks for any help.

 

The only difference between the 305 and 350 ECM is the chip. If the chip you got was for 350, then you're good to go. The 305 chip will even run the 350 in your type of TPI system.

Did you replace the knock sensor and module with 350 pieces? The 305 injectors are 19 lb, the 350 22 lb, but that really only makes a difference at WOT.

 

I haven't replaced any of the engine controls, but here is a list of the mods that have been done. Aftermarket chip (brother-in-law), hollowed out catalitic convertor (brother-in-law), Flowmaster cat back exhaust (me), 4" cowl induction hood (brother-in-law). Other than that, it's stock. Thanks for the info!

 

And by the way:

THANK YOU FOR YOUR SERVICE TO OUR COUNTRY!

Happy Veteran's day, Veteran!

Good luck with your car.

 

THANKS! It really means a lot when people say thank you, that's all we (me and my Marines) want, especially seeing as how we're stuck in Iraq right now. Thanks again.

 

For every one of us saying it, there are 1000 thinking it. Never forget that you are supported!

Many other vets and I feel your pains. I did all of 05 and most of 06 in Afghanistan. I may volunteer to go back again next year. I used to be a SEABEE.

Keep up the good work!

 

9 years active, one year Guard. The only bullets that flew over my head were at the rifle range.

Ditto - many, many thanks. It's worth it, and it's working - if we can just get the idiots in charge of congress to get over their Bush hatred and let what needs to be done get done and stop aiding and abetting those who wish to destroy us. You guys are doing it right.

 

I'll hit 14 years on active duty while I'm out here, and without trying to get myself in trouble, I'll just say I aggree. Any how, thank you for all the support and information, I really appreciate it.

 

SEMPER FI Devil Dog