SBC Block Question

[johnnymac46]

I am building a 355 for my 68 camaro. I found a complete running 4 bolt main,350 pulled from a 89 k5 blazer.

My question is what is the difference in between pre-86 SBC and the 87-95?

I have a rotating assembly from a buddy for next to nothing already, minus the pistons.

I was thinking about running a dart top end kit from summit(http://www.summitracing.com/parts/CMB-09-0002/Application/?query=Year%7c1989&prefilter=1)

I have worked on 350's in the passed they were all pre-86 motors, I just want to make sure there wasnt any changes that are going to throw a wrench in this build if there was any changes at all

[camcojb]

in 86 they swapped to a 1 piece rear main seal. Crank is different than the earlier ones.

[deuce_454]

you can get a 1 piece rear seal adapter to run the new crank in an old block... but the other way will IIRC require mashining the crank.. not a big deal, and most machine shops can do it..

[johnnymac46]

Thanks for the help. I think I clicked on the first 40-50 google links as well