What do you guys think? Just curious if it can be done or is even worth wasting time on.

The compression height of the 230 and 250 are different. The 230 piston will stick out of the bore on a 250.

Nice little bump in compression, as long as the rings stay in the cylinders Negative deck has been done before, hehehehe

Ok, that makes sense. I knew the compression heights were different. Thanks Tom. Wonder if a shorter rod could be used?

The pistons should stick out just under 0.25". Trust me on this one... Here's what it looks like when you put 250 pistons in a 230.

The distance you are showing there includes the crevasse volume of the piston so is misleading. The difference in stroke length is .280 so the crankpin offset is .140 difference; you see that reflected in the two pin heights 1.795 for the 230 vs. 1.655 for the 250.You will find more than the +/-.007 tolerance in the deck height dimension in most blocks also, which adds to the problem.

Thanks for the details. The pistons were short enough to bring the expected 130 PSI measured compression down to 105-108 PSI and make the car run like crap. If someone were big into geometry, I'm sure they could calculate via pressure differences and get to the same answer. That person isn't me. :-)

Mark

Interesting, so the pin heights are:

replacement 250-----------------1.640
stock 250 & replacement 307--1.655
forged 307-------------------------1.672
stock 307--------------------------1.674
stock 230--------------------------1.795

pin heights are:

replacement 250-----------------1.640
stock 250 & replacement 307-----1.655
forged 307----------------------1.672
stock 307-----------------------1.674
stock 230-----------------------1.795
12Bolt.com Forged 250-----------1.67
12Bolt.com Forged 292-----------2.043

Just to add to your list

Thanks. IntegratedJay and I were just talking about that not too long ago and didn't have your numbers.

Good stuff to know!

@tlowe #1716 Speaking of static and dynamic compression calculation factors. Do you have intake ABDC degrees specs for your cams like the Hy-Tork and others? I'm wondering if any are the same as the stock 48 degrees ABDC like the stock cam to conserve dynamic compression?

I used Sealed Power 295AP pistons for a 307 from Rock Auto. I think I paid $75 and my compression now is about 9.5:1.

Did they have the chamfer around the edge?