Hi Rhys,

Your right, it's a quick fix to a poor fuel problem. The correct fix would be to remove the head & open up the combustion chamber to lower the compression. My current motor is one of my old bigbore hillclimb motors with big cam & 48mm Delortos removed & D grind + K-Jet fitted. It still has 11.5:1 compression :/
I welded up the distributor advance & filed it open again so it only gets 20 degrees of total advance from 5 at idle. Any more timing & it doesn't make a pinging noise, instead it goes directly to the dreaded KLUNG KLUNG detonation noise that causes your anus to tightlty grip the seat cover fibers. :)

Volvo clearence ramps are linear unlike modern cams. Makes no difference what clearence you set them to (less than .030") as the velocity at which the gap closes up remains the same. It's 3 degrees/.001" of lifter rise on C & D cams. Only possible reason the noise can change is differing positions in the wear slot on the rocker arm. I set mine on the highend. .018" for A & D, .022" for C.
I did use .014" on the inlets to reduce fuel problems until I modded my dizzy. Never set the exhausts tight. I soon as the exhaust valve cracks open the power stroke is over!

I like John Passini's writing with regards to Weber emulsion tube selection: "Far easier to choose a date from the Miss World competition, at least they all perform the same function" :)

Cheers,
Paul.