Does anyone have a FSM or any other "offical" oem specs on this cam ? I'm planning on running stock eliminator next yr with a 1970 383 challenger. According to NHRA,the cam specs are different on the 383 magnum from 70 to 71. I have the FSM for 70. What I have is below on cam lift. NHRA hp rating for these 2 engines are only 1 hp apart. So running my car as a 1971 may be a better choice, but I'd have to buy a grill/tail lights at roughly $1000. So I need to verify cam specs and make sure there isn't a typo in the nhra docs.


1970
FSM: lift = .450/.458
NHRA: lift = .455/.470

1971
FSM: lift = ?
NHRA: lift = .467/.483


thanks

Hi. My 1971 Service Manual calls for .458" on the 383 Hi. Perf engine.

Garth

You only need to concern yourself with what NHRA thinks it is. You need to access the NHRA Blueprint specs on the NHRA website. That is what the people you will be racing have done

Garth, Is that the lift on both intake and exhaust ?

The numbers I already posted were directly from NHRA's site.... If there's a typo in their documentation, I want to let them know......if it's in my favor of course.......so to do that I need rock solid OEM numbers. I don't know what's better than the FSM.

here is the second page

Garth

Garth,

Thanks for the scans. Pretty interesting actually. As most would have guessed, the FSM shows both 70 and 71 magnum cams having the same lift. NHRA shows the 71 with more lift........

Best double check the pistons specs as well. I thought a 71 383 was low compression.

Sheldon

True. Less compression, but more room to play with the cam on the 71