Otto head gaskets - check detailed instructions on Drags' website for tightening if you don't have them to hand otherwise.
How many miles has it done since rebuild - are you still running in - do you need running-in oil rather than straight 40?? See other recent posts.
Check engine mounting nuts/bolts.
I can never remember which way to tension the adjustment nut to maintain primary tension correctly - the gearbox wants to pull one way under load - loosen pivot bolt before adjustment and tighten after.
Is there any need to remove the inlet manifold unless you suspect a leak?
Some oil down through the rocker boxes to get some to the cams before starting.
I'd be inclined to kickstart or turn the back wheel in gear without the plugs in until oil was returning to the tank with bubbles. Morgo might need priming.
Apologies if all this is obvious to you!!
One last thing - keep badgering me until mine is on the road