I purchased an complete 502 mpi Mag 1995 that needs to be reworked to replace my 310hp 454.

I want to keep EFI/MPI but pump the power up. Im figuring an 509ci, get headers, roller Cam kit & reprogram, Free flowing air filter. How much can i get?

Would like 500-575HP but from what I have read. Its about 500 max w/ efi unit? What about fuel rail/injectors? Whats the best performance header for salt water? Im no opposed to doing other mods just would like them to be worth the HP.

Just to give you an idea. I have dart block 502's that are actually 509's with 250 B&M blowers and I have 605hp at 5500rpm. I have to use super unleaded. Also, my engines are rollerized. Single 850 Holley Carb. I heard you can get about 600hp if you bore it out to 540 cubic inches and have aluminum heads and the right setup, no 250 blower.

I am just starting to look at the same thing so I am very interested in how this thread develops. I am looking at the Whipple package. About $7k. Their website says it is a direct bolt on to the 502 Mag and good for about 600hp, ecm reprogramming included. I have don't know what other mods are necesssary like cam, rotating assembly, heads, exhaust, injection, or whatnot. Does anyone else? Anyone done this upgrade?

I dont have any input but interested to see how the thread turns out. I am kind of a believer that if you want good reliable power then you are not going to bet "bolt on" power. I am almost positive in saying that if you want a blower motor, then build one for that intention. I think the idea of "bolt on" superchargers is misleading and will leave you in a mess at the end, but just my 0.02.

I build 540 motors on the side for something to do. I am a retired pilot and I have built several 540's using a dart Big M block, Callis stroker crank, Manley H-beam rods, JE pistons, Total Seal rings, Custom roller cam and Brodix aluminum heads with Manley stainless steel valves and inconell on the exhaust. My average dyno numbers are 650 HP with a single Holley on top and no supercharger at 5500 rpm. The compression ratio is approximately 9.6 to 10.0 and you will need to use 93 octane. I dont see where I can add a pic for you of the dyno sheet, so if you are interested in one...you can email me at [email protected] and I will send you pics. I can also send you a link to my best buds motor that I built for him 2 years ago along with a dyno sheet. This motor is very healthy.

Call Ron I'm sure he will be very helpful with your questions

941-758-5942

I agree about not just bolting on power. All the internals need to be changed if you want something reliable. From a thread that I posted several weeks ago about what I can do with my dart block 502s, I found out that if I bore my 502 block to 540, change all the internal, get aluminum heads, add a Whipple 3.3 Blower with Intercooler, add more fuel and I should produce between 900-950hp. You will have to change out everything though. I am planning on doing this to my 1994 Cigarette TOP GUN. But I have to get new drives first. I will destroy my bravo 1's. I am going to go with Arneson Surface Drives when I can afford it.

Ateco has a few choices that are work very well.
502 into a 540
502 kit that makes 625 hp no blowers.

http://www.offshoreonly.com/forums/n...502-540-a.html

http://www.offshoreonly.com/forums/n...c-500-efi.html

Do you have a tune for the +125 for 500EFI setup that will work on a 502MPI? Basically using everything in that kit with exception of MPI induction instead of 500EFI induction

540 is not in the cards now. I pulled both-complete motor/1 short block down tonight. Both are in really good shape. Either a EFI motor or build an carb motor? Leaning toward an EFI still. How to make HP500-575 Is the question? Where is Raylar-Young performance-other experts?