What would happen if I took a bone stock 502 Magnum and just replaced the stock heads with some AFR 305s? Would I get anything noticeable? What else would I have to do? Exhaust, reprogram I presume.

Thanks

Heads only.......maybe 20-25hp. Problem is, would you actually feel that amount? You would need to do a cam swap , exhaust and remap. My guess would be 60-70hp all in. Hey, but I'm no expert.




Darrell.

That is a great motor to upgrade. If you where going to put up that kind of money for heads, I would also do a cam and extrude hone the lower intake, also some good exhaust. That would wake things up. You would have to reprogram the PCM also.

I agree, good engine, lots of forged parts. I only have about 200 hours on it so it is ripe for work. Heads, cam, exhaust, reflash would probably add up nicely and be reliable.

I just finished a project just like that. I took my 502 mpi's and used well ported DART iron eagle heads, new cams, new valve train, intake manifold modifications, new exhaust, new fuel system and reprogrammed ECM's. Now I have about 540 CHP at around 5500 RPM's...and it still idles like a charm at 700 RPM's.

I figure it would be alot more HP than 20-30. I saw a test where one of the magazines took a 502HO 450HP iron head motor, and they bolted on a set of Eddy rectangulars. 50HP gain. And the AFR's flowrates are superior comapred to the Eddy's. Put some cam in there, I would expect the new combo to be at least 100HP over the stock combo.

probably could do it without a cam change or removing the shortblock, drop in some new lifters and top off the AFR's with bigger valves and some 1.8 roller rockers. the mag cam has decent duration just not much lift.