what is the estimated horsepower and torque rating for a 1968 stock 390? i have looked on the internet and one site says different form another! thanks guys!

 

1968 would have had 2bbl, 4bbl, and 4bbl GT versions. Not sure the 390 was offered in PU's in '68. If so, output would be a bit lower than the car 2bbl as the PU engines had lower compression.

FE Series Engine Specification Chart

Note these are SAE gross HP ratings, and high performance engine ratings are almost always suspect in 1960s vehicles, due to game playing by auto makers to try and fool the insurance man and the safety hand wringers. What could be unsafe about 500 horse in a car with numb steering, and tiny drum brakes....