Help! Just finished prepping my 350 and found small scratches and a small rust pit in several bores which I didn't notice before. I was going to use hyperutectic speedpro pistons but can't now because I'd have to hone to far past recommended piston/wall clearance specs. I have a stock 4" bore right now (which I was intending to keep). I'm building the motor on a budget to replace my just-retired 305 TPI. Keep in mind I'm using a hypertech 305 chip w/MAF.('86 IROC-Z)I have GM forged rods, ARP bolts (main studs), and a nudular iron crank. I don't really have much money to spend on boring, and I'm also worried about having to balance the rotating assembly(now that the mass changed). Can anyone help? I'm using ported 416 305 HO heads and stock ported TPI with a Crane Compucam 2040. I found a set of TRW forged pistons with a slight dish for 305 heads, .040 over for $100 new. I'm just trying to build a decent motor without spending $$$ I don't have. Thanks to anyone who can help!

 

what was your question?

 

 

I guess the question is actually a suggestion. Do I wait, balance and bore for .040 over TRW pistons or try to get by with standard bore hyperutectics? I'd use the TRW but it'll cost alot to balance the rotating assembly. I was planning on keeping a standard bore.

 

Given your situation, I would say let the machine shop make the call. If you can get by with just a honing then do it. Even with extra slop in the bores the hyper-u-crackit pistons will fit tighter and seal better than the TRW's.

ODB

 

The hypers don't absorb as much heat and expand like forged. That's why forged can sound like diesels and hypers are run much tighter. They won't work well if run that loose. I understand you're on a budget, but get the right pistons for your bore. Balance it no matter what. Do it once, do it right. Why 40 over? If you're not running a power adder or detonating, save some money and buy hypers instead of forged.