I was thinking: How did I miss this post??? GEEZ. Then I saw your post, Tom. I'm almost never in the General section… SO anyway I'll chime in:
For the sake of authenticity, the Pontiac badged 215 was the Olds configuration. I actually gave my extra Olds F85 engine to Tony (Hoffbug) in my neck of the woods. I hope he turns his into an Astre. His donor has all the parts… You hearing this Tony? LOL!
As many of you know I'm building a derivative of the 215 in stroker form. It's almost 300(299) cid now. It's been really fun to build. It's not cheap though. Just building a 215 would be less expensive. There are a couple ways to increase compression and add a little displacement.
One way I've figured out recently is to offset grind the rod journals: The stock 215 leaves the piston 30 to 40 thou down the cylinder. You could have the crank offset ground like 30 thou and add the OS bearings. You end up with like 225 I think. SWEET! (that's with a 40 overbore) It also helps the GIGANTIC rod ratio (2.02:1 YIKES) a little, changing it to more like 2 or 1.99 I think. That's still pretty steep.
This also helps the compression ratios. The engine can handle some wicked compression like Dwight was saying. If I was doing it again I'd try for something more like 14:1 and run E85. Since it burns slowly and more stably it runs much better at higher compression. I also think the long rod ratio will will take better advantage of the slow burning fuel.
For those who are naysayers of E85 read the latest CarCraft HP competition. The one common thread of EVERY engine that placed at the top is E85.
OK that said 13:1 compression with pump gas isn't out of the question and the bottom end is really pretty tough. The stock rods are nice forged units and stress on the short crank is minimal. I don't know of a broken 215 crank. In fact, the bottom end is really optimized for higher RPM. The limiting factor here is the head/valve geometry. In the 60's there was an Australian racing engine producer that just slapped OHC indy heads right onto the stock Olds block and ran them in Formula and Indy cars at high RPM. Pretty cool. Here's what they looked like:
http://www.repcobrabham.com/
That's right, buried under all that head gear is the lowly Olds 215. AWESOME!!