340 Modifications

Verify when you take off the cylinder head. If it is a high comp. engine, the pistons will pop out of the block a little bit.

Do you have headers?
Do you mind changing converters?
Or gears for this swap?

Best is also an opinion. Unless someone dyno'd a buch of shafts to compare.

A cam in the area of 218 - 224 should do well with the stock converter. I'd look for a duration split of approx. 8*-10* with stock unported heads. 6*-8* for light porting. A centerline of 110 will have a chop to the idle. Quicker ramp cams add to the sound.