How to make a gen V 502 MPI + $5K = 600 dependable HP?
 

Looking for some idea's for my winter project boat. My buget is about $5K on the motor and I'd like to end up between 550-600 dependable HP. The motor has an unknown history other than- its a freshwater running 95 Merc. 502 mpi Gen V with approx 420 hrs. I'll have it leaked down next week and plug it into the scan tool as well.

Would love to just throw a Whipple on it and be done but with the hours and unknown history I'm afraid it wouldn't live.

Thought about maybe selling the motor and going with a 509 or 540N/A motor. Any idea what the motor would be worth?

Any ideas or suggestions would be appreciated

Check out Tyler Crocket I actually have my ECU's going to him to be reprogrammed to go along with my engine rebuilds.
http://www.crockettmarineengines.com/about.html

He has done some great things with the 502's. Also look at this thread. http://www.offshoreonly.com/forums/s...=tyler+crocket

Bore and stroke your 502 for a 540. I did one with buying a new 502 block for less than 5 grand.

Only way dude!!


Do what I did and put the Whipple Charger!!

625 HP.....no problem!!
Dependable,,,,dock friendly.....I love mine.

You can find a good deal if you look on one.

Good luck

I did two 454's for 6k but they only made 505hp.....cant help with the MPI......I think Whipple!

I think you can get the HP in the low 500's with the MPI for that amount of money. Freshen the engine, bowl blend and larger valves in the heads, cam change, reprogram the ECU, new fuel pump and good exhaust. To get near 600HP you'd have to ditch the MPI and go to a good intake/carb or aftermarket EFI and a more radical hydraulic roller cam. The Merc EFI makes good low end torque but becomes a bottle neck at the higher RPM needed to get more HP.

Bob,

I was hoping that you would join in on this one.
ST31

AZ Speed & Marine has a Merc MPI manifold with shortened runners (also Extrude Honed) which should help a little with the HP numbers. Still not 600hp, of course.

Bob,
When you say "freshen the engine" what exactly do you mean and what should it cost. It seems to be a pretty nebulous term that ranges from a new plugs to a complete rebuild.

Sounds interesting but wouldn't it be easier to buy one allready built and sell my 502. Seems like I've seen some 540's for sale in the back of Hot Boat mag for around $7500.