HEY ive heard putting 318 magnum heads on my 360 magnum engine would give me a slight power increase, i know the 318 has a 9.1:1 compression ratio and the 360 has a 8.9:1 compression ratio, so will it give significant power increase

 

i think you might have your info a bit mixed up. last time i checked the 360 had a higher compression ratio than a 318.

 

i found my info on allpar.com, i dont know how reputable the site is, but still does a head swap give performance gain like 305 heads on a 350?

 

there is so much different info on that website for so many different versions of the same engines that it would be hard to tell if that info applies to you truck. i know the stroke on a 360 is suppose to be greater than the 318 which would leave me to believe the compression ratio to be more

 

360 Magnum has dished pistons, 318 has flat tops. The Magnum heads are identical though so there is no performance gain.

 

i think you might be looking at information on the LA series small blocks 273-318-340-360
and on those engines it might make a difference but requires intake from a 273-318 also if you do it ...and its not worth it in my opinion...the loss of flow from the smaller intake/exhaust ports ....you would be better off having a machine shop deck the heads...make sure they deck the intake side to the correct ratio so your intake will fit back on correctly