I'm building a short stroke 270 engine and am wondering what others have found a PROPERLY built engine will reliably wind to.
The stroke is still very long but with properly prepped rods: polished then peened and balanced with ARP fasteners and the counterweights weighted to go with the piston weights etc.?
Have others found it necessary to fab steel main caps?
I only wound the standard stroke 270 I built without the special treatments to 5000 and it held together so I expect lots more as stated.
This is for a track roadster I dug out of a backyard here in California.
Roar
The main limiting factors that will keep you from be able to buzz these engines very high is a relatively poor flowing cylinder head, and camshaft selection. Most of the high revving engines that others have been able to achieve this with are using the very pricy 12 port aluminum heads, or with the stock heads ported to the max and much larger race profile camshafts or both. Even the stock heads ported step by step in the California Bill book are still only able to reach the low 200 CFM range on the intake ports. Other 21st century techniques used by others have so far been able to get these heads a little higher into the 230 CFM range, and along with a custom camshaft have been able to get these engines to turn beyond 5000 RPM. With the newer cam technology and cylinder head development that is currently available, the sky is the limit, but it also is very expensive. All the high tech ARP bolts and polished beams don't help out much with RPM when you have a 10 pound piston on the end of the rod trying to pull it in half. The rest of the engine as well has to be modified to endure the extra RPM also. The only way to get a much lighter piston for the GMC's, is to install a much longer connecting rod, so a custom compression height piston can be made that eliminates a lot of the piston mass. Both are very costly. In the rare chance you can even find a cam company that has a stock type cam core to grind you a decent cam profile with, the only other alternative is to regrind a stock one, but you are limited as too how much bigger you can regrind it. I have been working with a camgrinder to develop some brand new billet roller cams for the entire early(Chevy and GMC) and late(250/292)engines, as well as any other inline possible from the Flathead 6's to the Straight 8 Buicks and Pontiacs, and everything in between, and are available now with just a phone call. So before long it will be possible to have a 21st century vintage engine in a lot of ways....