SpeedMaster Heads for a 5.9 Magnum
Looks like I may be better off just getting a set of remanufactured heads or new heads if I can find them that are iron and upgrading the valve springs so I can run a bigger cam. The build nots gonna be radical.
Yes and no. More flow, more power. More flow isn’t limited to the high lift nor is it limited to the top end rpm or speed factors. A good valve job, minor bowl work is what MPO shows and it improves the low lift and low to mid rpm range really well. IMO, with the Black Friday sale going on, (and if I were in your shoes) I’d get a pair and send them out to be worked on. MPO could easily do the work for you or if your more comfortable with a local guy, that’s fine as well.
MPO has been fooling around with these for a while.
These heads will out flow the iron heads IIRC, stock OOTB or worked on equally. So, I’d run the better head. All ways purchase the best head possible! It’s the best power return you’ll get. Mild or wild.
Looks like if I run the aluminum heads I can’t run the stock valve train set up???
That’s correct. When you look at your cam, one with the most lift to work with your heads is what you’ll be looking at. A quick valve lifting cam is what you seek. The rocker ratio won’t matter. Just the net lift.
The Comp rockers are an additional cost, but worth it in terms of an accurate ratio and strong rocker.
Also by running the aluminum heads, there an LA intake manifold pattern which opens up choices and used ones are all least cheaper.
