Hi, wonder if I could ask some advice.
I got a head with 33 and 29mm valves that has had some porting and flowing. I have cleaned it up and been preparing it but just measured the chambers and they vary from 18.3cc to 19.7. Basically it looks like the inner 2 are 19.5 and the outer 2 are 18.5cc when allowing for minor measuring inaccuracy.
To me this seems like just a bad job been done but is there any reason you would make the Siamese chambers lower compression on purpose? It looks like they have worked the chambers out at the edges but not in the middle between the valves etc as this looks more course like the original casting. And the chamber depth is deeper for the middle 2 chambers from deck to between the valves. It’s like the original casting varied in depth and they didn’t take that into account when working the chambers out.
I guess if I ground it down on the outer 2 then I can even them up but is 1cc a lot to ground out? I have the tools but not done it before.
Any advice would be great. Thanks guys.