53 flathead horsepower

In original equipped 239 engines max power was actually around 80 HP. Advertized Horsepower has nothing to do with the engine.
 
OL' Ron is right. Horsepower is one of the most illusive terms used. I guess it's whatever you want it to be. I know in the '70's during the horsepower race the factories got completely carried away with their advertising. The gov't made them cut their claims nearly in half. My '70 Ford 302 had 200 hp. In '74 it had 120. Same exact engine. 80 is a good number for a stock 239 flathead in good condition.
 
Had an opportunity a number of years ago to use a drive on dyno, so for Ha'Ha's decided to give it a shot. Unfortunately my Merc. is too low and without some added ramps, the test could not be done.
(Probably saved a little embarrassment) but would still like to do it just to put some horsepower guessing to rest.
 
4t8v8 said:
OL' Ron is right. Horsepower is one of the most illusive terms used. I guess it's whatever you want it to be. I know in the '70's during the horsepower race the factories got completely carried away with their advertising. The gov't made them cut their claims nearly in half. My '70 Ford 302 had 200 hp. In '74 it had 120. Same exact engine. 80 is a good number for a stock 239 flathead in good condition.
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The factory horse power ratings changed from gross to net in '71-'72, resulting in the lower HP numbers, followed with reduced compression ratios to comply with upcoming lead free gas and catalytic converters. That '74 302 wasn't exactly the same as the '70. :)
Many of the high performance '60s engines were actually underrated for racing and insurance reasons.
 
Actually it's the torque numbers within your driving rpm range that matters most, IMHO.

Horsepower numbers tend to be used in sales hype advertising and the advertised number is probably seldom reached, if ever, in normal driving. Again, IMHO.

Flat32:cool:
 
4t8v8 said:
OL' Ron is right. Horsepower is one of the most illusive terms used. I guess it's whatever you want it to be. I know in the '70's during the horsepower race the factories got completely carried away with their advertising. The gov't made them cut their claims nearly in half. My '70 Ford 302 had 200 hp. In '74 it had 120. Same exact engine. 80 is a good number for a stock 239 flathead in good condition.
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Well no, it was not the same exact engine. The '73-'76 302 engines had higher deck heights for lower compression, dished pistons, and retarded timing gears.
 
JWL's book takes a stock (.040" over??) and runs it through it's paces. Making every modification you can think of, with bolt on "stuff", except a blower. And never got a 100 HP from the engine, till he changed the cam. This is a very interesting read with all the mods dyno tested. Thanks John.
 
Ol' Ron said:
JWL's book takes a stock (.040" over??) and runs it through it's paces. Making every modification you can think of, with bolt on "stuff", except a blower. And never got a 100 HP from the engine, till he changed the cam. This is a very interesting read with all the mods dyno tested. Thanks John.
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Agreed. John's book is great!
 
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