Any difference in flow between the various 440 HP exhaust manifolds?

[Grec]

Looking at the 68-69, 70-71 and 72+ 440 HP manifolds.

I see obvious differences in the heat riser and basic look, expecially in the 72+, but is there any real difference in flow characteristics?

Did they get more restrictive as time went on to comply with the hardening emissions requirements?

Thanks.

[moparnut]

I think you answered your own questions......The 68-70 flowed more than any other years

[Chryco Psycho]

the big block A body was the most restrictive by far , I doubt you would see any significant difference in the others , the C body had a different outlet position on the left side

[Grec]

Thanks, guys.