From a friend I purchased a used OS 35S modified by Randy. My friend had very artfully ground the front portion of the head fins off with concrete. No problem, I would just replace that head with one of my un-marred heads from a well used & retired OS 35S. Surprise! Surprise! When I got the heads off they were two different animals. The newer ground down head extended noticeably deeper into the cylinder & had a more pronounced hemi shape.
Does anyone have experience swapping these heads. No biggie? Will the shallower one change the 4-2 break making it softer?
Hi John
It sounds like one of my Special Smith OS 35S engines, the head is a higher comp head with a better chamber, most of them also had either Bushed I Beam rods, or Hard vented rods , with special wrist pins with teflon pads, heat treated P/S and either blue , red, gold, anodized head, venturie and drive washers. Does that sound like yours?
You can use a stock head for it, but it will be just a tad down on the power output, so use a bump in nitro or prop pitch
Randy