newer motor with older clutch

[CBLAZER81]

the motor blew in the 81 blazer and I'm having a helluva time finding a good block. Picked up a '90 350cid today and realized the bolt pattern on the crank,for the flywheel,is different.
My ? is, will the bolt pattern on the old clutch match up with the newer style flywheel? I don't wanna have to buy a new clutch.

 

[CBLAZER81]

Anybody? I need help on this one.

 

[dyeager535]

Are you saying you HAVE the one piece (rear main, newer block of course) flywheel and are curious about the pressure plate/clutch, or are you wondering if you need a flywheel for the newer motor?

I can't say for sure on the clutch/pressure plate (although I'd imagine the bolt pattern on the flywheel stayed the same) but you will need a different flywheel, I'm 99% sure.

If the flywheels interchange from like '59-86, (approx, IIRC, one piece came of being in 1986) and '86-up, then you'll need a new one.

 

[CBLAZER81]

Yes,I HAVE the newer block with the one piece rear main seal. (builder block)
The old one is the older style,2 piece rear main. (blown up,still in truck)
I found out this morning that they used the same clutch from (approx) 1978-1994. So my old clutch SHOULD bolt up to the newer style flywheel.
Thanks for the answer though.

 

[loudnowlouder]

yes it will fit
i had an 85 305 with the 2 piece rear..
swapped in a crate engine with the one piece, got a new flywheel and the old clutch fit fine...the main bolt pattern is the only real difference in the flywheels, still the same diameter and # of teeth...no reason for them to make a new pressure plate pattern as well....

just make sure you check the clutch out real good, it's easiest to swap in a new one now, but if this one is fine and money is an issue, bolt on what you have