Hi to all, my name is John and i have a 86 cutlass supreme. It currently has the 307Y motor in it and im replacing it with a built olds 350 and upping my rear gears from stock 7.5 rear to a 8.5 with posi and 3.42s.

 

Welcome to CO, John (aka Mr. Lightning!). You'll like it around here. Sounds like a neat car, w/the upgrade to the 350. Pictures are always welcome!!!

 

Welcome aboard

X2 Post pics pronto please

 

Ill post pics of it in the spring when the weather is more condusive. I had pics of it on my computer that i couldve posted but i lost them when my hard drive crashed. Thanks for the welcome!

 

 

Welcome! I have an 86 Cutlass also. I would love to see a detailed thread about replacing the 307 with a 350. My dream for sure!

 

Welcome to CO John.

 

The swap of a 307 to a olds 350 is a direct swap and all accessory brackets are the same. The only issue that i understand isnt a big issue at all is the fact that the original 307 is computer controlled by the ECM and the A/C is controlled by the ECM, hence t he A/C won't work unless you do some rewiring, like as an '85 or earlier is wired. It's pretty basic, '85 or earlier the compressor is controlled by the pressure switch, '86 and later the pressure switch is an input to the ECM and then an output of the ECM turns on the compressor. But beware it has to be an olds 350 and not a chevy 350 for it to be direct swap. Chevy 350s will fit but all your accessory brackets for the olds wont work and your engine mounts are also different. Im really looking forward to doing this swap and getting away from this dog slow motor 307Y. Even the HO 307 vin 9 motors were nothing to brag about in the 81-87 442s as they were only rated at 170 hp.