Thanks for the info. and I'll look into the breather issue.. at present the only thing on the engine is the stock valve cover breather and the pcv valve. That may solve the
oil problem.. as for the backfiring. no it's not on decelleration.. it's on accelleration, any gear from stop all the way up.. both sides. and it's in the exhaust. not the carb. In essence I guess you could almost say it sounds more like pre-ignition but that's timing for sure, at least in most cases, actually sounds like a machine gun...spitting and sputtering maybe backfiring was not the right term to use. We have checked, checked and rechecked the timing. The vaccuum advance has been disconnected and it's running strictly on the mech. advance. initial timing is set at 12 degrees with total being somewhere between 34 and 36. I told the engine builder today that both I and Brian felt that it could be in the cam and his answer was "no way in hell" could the cam cause backfiring in the exhaust.. it has to be timing.. my answer was uh-huh sure. and it's up to you but if I get it back and it backfires one time the you know what is going to hit the fan. I agree with you on the valves as potential problem areas.. in my opinion they are the most likely culprits. Either not seating properly or sticking or something. I'll pass this along next time I talk to the builder or to barry as Brian is on vacation for 3 wks.