Joe,

You mentioned the single bolt on which the heavy air cleaner hangs from the end of the exhaust manifold.  Well here is a shot of it for those not in the Wallis 20-30 (and earlier Wallis tractors) club.

This submission should really be in the tractor design faults thread!  One wonders why those Wallis engineers didn't tumble to the idea of mounting the air cleaner on the block as they did on later tractors - so obvious really and what a nut idea to hang it on the end of a manifold knowing the frailties of that type of steel.

Hope viewers can see the single bolt head on the right end of the manifold on which the cast air cleaner below hangs

John