-- Tom Jennings <tomj@xxxxxxx> wrote: > Odd, the TSM doesn't mention valve diameters (but I found those in the > Datson book) nor exhaust valve timing. > > Anyone have that info? I'm running my ancient copy of desktop dyno. Thoug I don't have exh timing, I left it as 0 and 0 for now. Started fiddling values to see what would improve performance "on paper". When I did this to the 258, most of the changes matched what is known by listers to be good. Funny with this motor. Things like valve size and lift, carb and exhaust, nothing makes even a 1% change! Though it's got to be a bald-faced guess, "pocket porting" makes for a big change. I didn't look at the head with an eye towards flow (not that I know much more than the basic idea) I imagine it's pretty lousy. The power curve matches what we do know about this old motor, power peak is around 3500 (that 4500 claim in the TSM sounds suspicious...) I haven't heard this motor ping even once, so I probably have a lot of latitude for ignition timing advance. But with the low speeds and all the lugging pinging would be a bad deal. Does anyone know, is pinging in the motor very audible? _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list