1953 Ford jubilee won't start?

I have replaced plugs,plug wires,distributor cap points and condenser,coil,carb., tractor has been rewired,new battery,new switches,exhaust manifold was checked for cracks, compression was checked and it still will not start and it has plenty of fire at plugs and plugs are wet with gas. When I had the exhaust manifold off I shot some gas to each plug and it shot flames out exhaust ports? Any help would be appreciated.
Thanks Dave