A buddy of mine has a single engine cat with a hp500efi. He is thinking of adding a set of Merlin Heads (steel,SQ. port,310cc,2.19/1.90 valves, mild port). I told him that the gains he would get might not be worth the effort. Any comments? Hp?

Thanks!

Add a new cam, throttle body, long tube headers, ECU reprog. and you pull some of the numbers like the new 525.

We swap heads on 500's alot and it really wakes them up ,we like to swap to the 741 or 731 crane cam and add alittle comp. and retune the ecm ,but the heads are a great starting point just clean out the valve pockets