Will not start but tries

Newly rebuilt engine tries to start but will not. It is getting fuel and spark. It has a carburetor and has an HEI distributor. If I use starting fluid I get a small amount of black smoke from the exhaust.

I thought I should add, it has a high rise intake as well as a knock off Holley carburetor unsure of size it is either a 600 or 650. It has flat top pistons, the original 64cc heads, factory cam, roller rockers that are 1.6. Engine has ran with the original TPI setup but not good. I pulled the TPI to replace the factory injectors and broke the fuel rail so this is why I went non computerized.