wallynt

HELP...

Can someone tell me if an MPI set-up off a 99 502 MPI will fit on a Gen IV 502 Mag carbed? I have found a complete MPI set-up includes intake with injectors, plenum, cam & lifters, cool fuel and computer. Is it this simple or are there a lot of things to change?

Thanks for any advice.

Wally.

Pat McPherson

The Intake should bolt up fine.
I am not sure about using a Gen VI roller cam in a Gen IV block though.
If you use an aftermaket retro roller cam and have the ECM reprogrammed it will work.
Or you could leave your stock flat lifter cam in and have the ECM reprogrammed.

wallynt

The stock cam is toast so I was hoping the Gen VI cam would work. Don't really want to go the reprogramming route just looking for dependability and reliabiltiy.

Is there an aftermarket cam with the same specs as the gen VI that will work with the MPI and fit in the Gen IV? Or am I asking to much?

Thanks.

wallynt

Will a set of aftermarket roller lifters for a Gen IV work then?

Has anyone else done this swap before or have any other comments or input?

Thanks for the help.

Pat McPherson

There are definitely after-market roller lifters and retro roller cams of similar specs to the stock cam...
The stock roller cam is something like 224°/224°, .480/.480, 115LSA.
I would bet that a new Gen V 502HO flat cam would also work without ECM changes.
That cam is like 220°/220°, .500/.500, 114LSA.

Pat McPherson

If it were me, I would just buy a new Gen V 502HO flat cam and lifters. The Gen V 502s came with the same Merc MPI...
Gen V cams work in a Gen IV block no problem...
You may, but probably not have to reprogram the ECM.
A roller cam and lifters for a Gen IV block will cost 4 times what the flat cam and lifters will...
Its all a matter of how much $$ you want to spend...

wallynt

Thanks for all the info.

Maybe the MPI route isn't the best way to go.

Since I have to buy a new cam anyway, can anyone recommend a good cam/intake/carb combo that won't need alot of extra head work?

Wally

Tim G.

Stay carbbed.. My 502MPIs were nothing but a PITA.
I even thought about scrapping the EFIs and going to carbs....