It certainly looks like the old camshaft and followers have overheated. Either I tightened the tappets too tight, or the hardening failed, or a combination of both :/
Looking at the camshafts I see that the new one I have is a 67-356; the knackered one and the presumably original one I took out when I restored the engine are both 67-334's. What's correct for my engine?
I’ve a (srm) 356 cam in my ‘56 and it’s a straight swap with the 334, it’s generally accepted there is no downside to the upgrade to a 356 from a 334. The 356 was fitted to late GFs and early rockets. The later 357 cam as fitted to rockets can hit the crankcase of a GF due to its higher lift, but even this is easily fixed with a grinder
I don’t think you easily could buy a new 334 anyway. I’ve a box of used ones I doubt anyone would want!
My guess is your old 334 cam was ground to return it to shape and was not re-hardened afterwards, and the grinding went through the hardening layer, leading to the excessive wear you can see on the cam, it’s possible the followers had the same fault.
There is risk with re grinding A10 cams and followers that afterwards the tappets are not able to touch the cam base circle, there is not much extra movement in the followers before they hit the “stop” in the barrel.
It’s got to be worth a try hone and new rings (at most) isn’t it? I fitted new pistons on a used rehoned bore and 005 plus a bit clearance and it runs great, no smoke or rattles 7500 Miles later.
