Okay the time has come that im getting into my GTA, a little information for you all. My GTA has 166,xxx very very hard miles on the factory 350 2 bolt. So yeah I will be needing a new engine. I came into a set of L98 (113) heads and im planning on spinning this engine up to the 6000-6500 region. Now for all intensive purposes the L31 shortblock looks like a good option for me. Its cheap enough. Heck its dirt cheap really and it has PM Rods, Nodular Crank...but what about those pistons? Are they just kinda standard hyper-us? I mean will it hold up to a 6800 flash?

Also, im seeing here that the L31 SB is sold without a balancer or flexplate...I was kinda under the understanding that all 305-350 gen 1 1pc rear engines were externally balanced. Am I seriously going to have to try and find external balance stuff and put it on there? That would kinda put me out of budget for this engine. Buying a new balancer and flexplate...no thats just a good idea for any engine, but tearing down an assembled shortblock and getting it all balanced. Anybody say dealbreaker? If im going to be making trips to a machine shop I may as well assemble a cheap 1pc from a junkyard. It will seriously be the same amount of money.

And as far as it being "Just" a 350. I know that for a little more now I could make more power, but i am in the middle of a build that will be replacing this one. This engine is just an interm engine. I just want to keep my car on the road while I get the 383 ready. I mean I really dont want to be doing compression checks on that old 350 and praying the rod bolts hold up. That and man that old 350 has taken some SERIOUS abuse. And it just goes right on ticking. I really wanted to take it, rebuild it and put it in my pickup. But thats a different story haha.

So yeah any help with the info would be greatly appreciated!

 

Your current 91 350 balancer and everything else should go right on with no worries. Your 350 has a balance weight on the flywheel, but not on the balancer. I think all small block chevy 87 and up are like that right up until the L31 and that last of them.

I have never heard anyone complain about the RPM limit of any pistons unless they are running extremely lean. Or nitrous use is excessive, or or or... you know...

 

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The L31 block is the same as the L98 in your GTA now. They did not change the casting up to the end of production in 2002

L31 pistons are cast, similar to your current ones, rods and crank aside the difference is minimal

To spin it up that high Id suggest stronger rod bolts as vortec stuff revved only slightly higher than TPI stuff
Im with KrisW on the pistons, theres no reason to change unless you are doing something different and even then pistons are cheap