6.5 turbo in 6.2 NA clothing. Will it work?

[Pir8Darryl]

Hey guys. My 91 G-30 mini school bus has issues. Could be a blown head gasket only, or it could be worse. It's been sitting all winter waiting for warmer weather to come along before I start turning wrenches on it. While it's been sitting, I've been watching the local classifieds waiting for a killer deal on a long block to come along thinking I could snatch it up and have it ready to use if I tear into this thing and find a worse case scenario. I figured I could re-sell it if I didn't need it for what I paid.

Well, I struck gold yesterday. Got a 6.5 turbo motor for $175. It came out of a roll-over suburban with 91k miles on it. Complete motor fan to flywheel. I talked him down to that price because I didn't take the IP, turbo or exhaust manifolds.

I know it's an old trick to bore a stock 6.2 out to use 6.5 pistons, as this lowers the CR down from 21:1 to 17:1, and puts less stress on the engine, but I just want to double check everything before I give the project a green light.

Will ALL of my accessories swap over to the 6.5 long block? Will the stock 6.2 IP have any issues? Basically will this work to convert a computer controlled turbo 6.5 over to a non-turbo 6.2 environment?

Any assistance or advice is greatly appreciated

 

[towcat]

everything swaps over.
make sure the water pump plate is of the proper rotation CW vs CCW. if any doubt, swap over your current one.
be sure to plug off the turbo oil feed at the front of the block on the pass. side.
everything else is GTG.

 

[Pir8Darryl]

Very much appreciated Towcat. I may very well have missed a detail like the oil feed line.
Does anyone have any idea how my power will be effected? Loosing a little compression, but gaining a few CID. I'd like to turn the IP up 1/4 turn as this bus is a total **** when trying to climb a hill.

 

[lindstromjd]

Plenty of early 6.5's came without the turbo. They ran the same pump as the 6.2 did. Too bad you couldn't fit the 6.5 turbo set-up into your mini bus... that would definitely help wake it up.

 

[Pir8Darryl]

Yea, that would be nice, but unfortunately my wallet's a little too thin for those kinda upgrades.

 

[tanman_2006]

The 6.5L isnt 17:1 compression it is 22:1 just like the 6.5L. The newest GEP 6.5's are 20:1 and that is the lowest made from the factory.

All brackets should cross over just fine, you should have a little more torque with the increased cubes.