What is the new HP rating of SBC 1965 327/275 10.5:1 Compression ratio?

with dual exhaust headers, edelbrock performer alum intake, 600 edelbrock performer carb, 151 cam, C236 matching 461 2.02 1.60 fueli heads? I was told it is 350- 365 HP now. What do you think? Trying to reach 400.


1965 327/350 HP shows it had 11:1 CR so .5 off, same cam, alum intake, same carb size, same 461 2.02 heads, same exhaust. so he proved it to me. I get that GM used different HP rating than used today thanks. What was the amount that should be used than for 350 HP? Is it 325?

2 Answers

  • Anonymous
    1 decade ago
    Favorite Answer

    Your headers, intake and carb are pretty much o.k. The rest of it is junk. Get a "383" kit and install it, use some good aftermarket heads like AFR and a good cam, preferably a hydraulic roller. You will be there if assembly is done well.

  • 1 decade ago

    And what have you really changed? Who ever told you 350-365 HP needs to be slapped.

    The engine is pretty much stock 1965 specs. The headers and exhaust might have added 25 HP

    The stock rating was gross rated at 300 HP. In real life, net rating like all engines from 1972 up has been rated at, that one would only be 240-250 HP

    So you might have 260-275 HP.

    You have a LONG ways to go to get a 327 to 400 HP.

    You better look at some heads that flows 240+ cfm, 240*@.050" and larger cams with .550" lift or so, performer RPM air gap intake, etc

Still have questions? Get your answers by asking now.