check ECCS relays and connections, also fuel pump relay and fuse and connections other possibility is ignitor loom,
mine was brittle as, shorting everywhere. Check the connections to resistor pack both sides. Good luck.
There are small steel bushes in the cam belt cover that space the cas the correct distance. Make sure you have original mounting bolts for cam gear installed ,the original bolts have quite shallow heads.
The same thing happened with mine, I think the camshaft is pulled fowards very slightly as revs increase, I found very very fine aluminium filings on the back of the cas. Otherwise did you have lifter bores checked they can stick if they rock in the bores. Were small end bushes new??