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Old 04-27-2020, 12:47 AM   #1
phlegm
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Horsepower estimate

I think we got the back firing squared away today. I had a friend come over and help. First I took the carb off sprayed it out real good to make sure that the pin valve wasn't dirty or the ports. then put it back on the engine my buddy came over and we adjusted the timing to 14 btdc run smooth now pulls really well so my next question is what kind of horsepower do you think I'm getting? Its a 350 with a 3 speed on the column, long headers going to 2 and 1/4 inch pipes with flowmaster 40. Oh yeah and HEI, that's the reason the timing was messed up. when I put in hei I did not redo the timing. Anyway, how many horses would you guys guess I am putting out?

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Old 04-27-2020, 08:01 AM   #2
rpmerf
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Re: Horsepower estimate

Assuming this is the original engine on the 71. Factory horsepower would be about 255 gross / 195 net. Realize this would be closer to 165 HP at the wheels.

If the only modifications are exhaust, HEI, and timing, don't think that it will be making much power power than stock. At MOST, I would say 30 HP over stock, but I would be surprised to see more than that. All those gains would be on the top end, as the factory exhaust would be sufficient at lower RPM, but not flow enough at higher RPM. HEI is more of a reliability mod, it is not going to make more power than properly adjusted points.
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Old 04-27-2020, 08:13 AM   #3
special-K
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Re: Horsepower estimate

I'd estimate it could be less than rated depending on tune or if tuned and timed to optimum it could be 10-15hp more in higher RPMs. I agree, basically still stock.
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Old 04-27-2020, 08:47 AM   #4
phlegm
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Re: Horsepower estimate

Thanks guys, I never knew my original HP so this is helpful. I figured it wasn't a lot as we didn't make large changes (cam. Etc...)
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71 Cheyenne 10 - SWB, 350, "3 on the tree" AC cab
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2010 Acura TL
98 Mastercraft "FrankenStar" 225
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Old 04-27-2020, 09:35 AM   #5
Richard2112
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Re: Horsepower estimate

Torque/horsepower increases are more significantly made in the bottom end (stroke/displacement) and at the cam. Though carburation (or fuel system) coupled with intake and headers CAN produce more power, it's generally a result of something being left on the table from the manufacturer. That's not to diminish the potential of a good set of heads but as they say, "there's no replacement for displacement".
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