Planetman suggested checking the fiber cam gear for solid attachment to the steel hub. If the gear is separating and is well along you may be able to see the gap - or even find play. What I look for is oil streak stains emanating from the hub outwards - a sure sign that oil is working its way between the two.
As for the cam and choice of related parts--all the steel gear sets I've seen have twice the number of teeth as the fiber gear and crank gear--meaning they have to match.
I started with a B18 in a '68 144 and later transferred the K cam and all the rest of the parts to a '69 144 B20. My cylinder head is from a carbed 44mm exhaust valve B20 motor--milled a huge amount to bring compression to over 11:1. The cam, lifters and fiber timing gear now have in the neighborhood of 200K miles. I attribute the long life to the SB Chevy lifters (and tubular pushrods needed because the Chevy lifters are a different length than stock). As a serviceman I've had to change many worn out cams and lifters - even in motors that have had regular oil changes. I think the Chevy lifters and the cam just seem to get along better.
My car has been run in about 35 Time Trial track days and will rev to 7k with stock springs. Good luck with your build. -- Dave