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Thirty five years ago I had 1970 GTO with a 455. It had a crane cam, long tube headers, Edelbrock manifold, holly carb and an MSD ignition. Stock heads and bottom end. M22 and 3.55 posi. At the time it felt pretty fast. I was trying to gustimate how much power it really made. I figure starting off with the gross ratings of 360hp and 500lb-ft, taking a guess that net power at the crank in the car would be around maybe 310hp to 440lb-ft, add maybe 30hp for the cam and bolt on’s to bump that to around 340hp and maybe 450lb –ft…..maybe….. and then the actual rear wheel numbers would be something approaching 300hp and 400 lb at the rear wheels……..maybe…..?

What do you think It could have measured at the rear wheels on a dyno for that combination?

Trying to come up with an estimate to relive old Pontiac glory. I recently acquired a 1972 GTO that’s a completely numbers matching 400. There is no hiding the fact that 250 rated net hp from the low compression 400 makes this car as quick as my Subaru SUV… So I think that numbers matching mill and drivetrain would be happy to go into storage. Planning a build to produce more power then my 70 did 35 years ago……..


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