Originally Posted by SamH
Ahh, finally some numbers! Thanks heaps for that. I'll just have to take it at face value and accept that it's ok to use. I'll see if I can compare the two cranks and figure out if they're timed the same.
I've got the lightened flywheel, 9.5:1 pistons and dual plugged heads so hopefully all those bits will combine to make a nice poweful engine.
Actually the timing difference is where the key slot is positioned for the cam sprocket. It's just a hair difference. The slot is 3 degrees retarded which advances
the valve timing by 6 degrees
(cam spins half as fast as crank). There are several different opinions as to why this was done. Emissions regulations, to increase mid-range, or to improve idle. Your slotted oil pump, points style cam probably has strait 0 degree valve timing. Not sure, but I think the advanced cams came out with the bean cans.
I'm using the later bean can 336 on my /6. I've got light 9.5:1 1000cc pistons in Nikasil cylinders, titanium valve retainers, dual plugs, crank ignition, 1983 tranny with ultra light clutch/non-existent flywheel , 32/11 rear end , 2 into 1, and 38mm Dellortos (with spot on jetting). Gotta say I love this combo with the 336.