[justin72nova]

Why is it that the 1970 250 CID had more HP then the 71? Was it a different head? Carb? Intake manifold? Exhaust manifold?

I know that in 70 they started emissions standards.

Would parts from a 70 or 69 250 head bolt onto a 72?

 

[mychevyii20]

Compression is the usuall culprit for the power drops in those years, along with cam changes etc for emissions. Most likely the pistons and cam.

 

[veno]

1970 average compressions were between 9.5 and 10.5... with factory hp cars reaching 11.25 to 12.5....71 was the compression drop 9.1 to 9.5, faze one, faze 2, 1972 was the big drop...with most between 7.5 and 8.5.... if I recall right.. the 1972 ford CJ351C, in the mustang and Torino was the last solid lifter V8 of the big three...

yes 1969 and 1970 heads and cam will bolt to your engine... just make sure you use the tune up specs for the year you take the head and cam from....

 

[bowtie0069]

1972 was when they switched from net horsepower ratings to the SAE ratings which dropped a ton of power on paper, even though the engines didn't change.