Lt1 swapped cutlass won’t start but shoots flames !?

[Texas82GP]

Post some pictures of your setup. Pictures of carb and intake, distributor and wires. Also some wider angle shots that show all of the engine compartment.

My suggestion would be start with the basics. Disconnect and plug the fuel line from the frame to the fuel pump. Pull all the plugs. Disconnect power from ignition coil. Throttle wide open. Check compression and report back. Post those pictures first.

 

[cat herder]

Distributor is 180* out, if you dropped it in assuming dot-to-dot on the timing gears was #1 TDC. Dot-to-dot is actually #6 TDC, #1 is both dots at 12:00.

 

[Hurricane77]

Rockers too tight could be a possibility, I've done it.

Who installed the Cam? May not hurt to verify the Timing Gears are indexed right.

I chased a problem like this for months. Wouldn't start, just fire occasionally. Periodic back fire. Had air fuel and spark. Pulled the timing cover off and the crank and cam gear were aligned, all good there. Did a compression test and all cylinders were way down. So either the engine was junk or the timing was off. Pulled the timing cover off again, Pulled the gear off the cam and low and behold, the the tab on the cam gear had sheared off. Timing was varying every time I cranked it over.