Smitty

iTrader: (1)

Can I turn a 502 Mag EFI into a HP500 EFI ? Assume that I will rebuild these motors with all the good internals that a HP500 has, will I be able to reuse the 502 EFI system and who can I have recalibrate the ECU properly. I do all my own teardown and reassembly, so I would only be paying for new parts and machine shop labor, thus keeping costs down. They will also be dyno run before installation in the boat.

Basically I am just looking for at least 500 horsepower out of these engines and I will be adding Whipplechargers to them at a later date.


Thanks

Chase910

Tyler Crockett (sp?) Marine in Michigan has a package for the 502 to get 500hp which you can install yourself. I believe its cam, head work, which involves larger valves, a better exhaust and ecu reprogram. He'd be a good place to start. He also has experience installing a Whipple on his 500hp 502 package, so he can also tell you what results you can expect.

tomcat

You may have seen this on another thread but here's the short story. You can change to the HP500EFI cam, and upgrade the valvetrain with Crane roller lifters, roller rockers and new springs. Freshen the heads, but I think you'll benefit more from pocket porting the exhaust than from putting in larger intake valves, especially since you are thinking about supercharging later. The same goes for the intake. You could have Arizona Speed & Marine cut down the lower intake runners but it isn't necessary unless you plan to RPM the engine. ASM can provide the computer recalibration, but if you have the older computer you will need to change to the MEFI 3 for a supercharger later. You need it to understand the 2 Bar MAP sensor you will need for boost readings the the ECU uses to control fuel. If you are thinking supercharging put in the best head gaskets and head bolts, Cometic is popular now.

Add CMI headers and you're good for about 530 HP. I don't know what the Whipplecharger will give you, but adding the Vortech supercharger is good for 720 HP. This has been done many times by ASM so they have the calibration you will need. We don't know yet how much more we can push this engine with our larger supercooler, but we are working with ASM to find out.