Anyone know the horsepower of some older hemis, like a 1970 challenger or Plymouth gx, a friend of mine says a 392 hemi in a 1959 Desoto is 220 at the wheels

 

Which do you want? 70 challenger/Plymouth or a 59 desoto? They will be different. A 1970 Challenger with the 426 2x4-bbl hemi was rated at 425 hp, same for the gtx. The biggest engine in a desoto in 59 was a 361 cid firedome. Rated at 300 hp.

 

a 1959 ANY chrysler will NOT have a hemi. AND a Desoto will not have a 392. the dodge, desoto, chryslers in the 50s with 2 diff sizes of blocks. and none shared the same CI. the Chrysler had the 331 1951 to 1954. 354 for 1956 only. the 392 for 57-58. the ply cars did not come from the factory with hemis.

 

Ever hear of Wikipedia?

https://en.wikipedia.org/wiki/Chrysler_Hemi_engine