I'm in the process of tarring down a 94 and 95 model 502 mag efi engines.( cliff notes, my 94 developed a knock, and the 95 has been sitting for 4 years).

I'm not looking to rebuild it and make 650 hp that isn’t reliable. However I’m sure there are a few simple, on budget upgrades one should do to improve what is already there wile the engine is out. Like crane gold roller rockers and stud conversion. What else would you recommend on a reliable rebuild, that is turnkey friendly, and no reversion. Cam? Reprogram computer? If possible I would like to stay with stock manifolds.

Flat tappet cam motors ? Those respond well to custom cam grinds ,and can produce a hp500 style rumpety idle at 700 rpm with stock manifolds.i would have bob m make you a couple , prob wouldnt be too bad for 2 flat tappet grinds for the bump you would get on that particular app

Only issue I see is getting a proper tune if it's a mefi 1 like mine. Hope this goes well as a lot of others and myself wonder the same thing I'm sure.

Why do you say that Buck, because of the limitations of the MEFI 1?

Unless you're an adept tuner with the software and I'm not, not too sure how you would get a good safe tune. Maybe not a problem idk.

I've got a newer harness & a mefi 4 ecm I'd sell, if you want to go that route

I hope you've still got that when I need to refresh my mill. My MEFI 1 was already "flashed and locked" when I got my boat 15 years ago. She runs like a scalded ape and sounds/runs better than her MEFI 1 classmates. BUT, I have no idea what was done or who did it.

Is that all that's needed to plug and play, the harness and computer? Then our MEFI 1 motors will be more tunable?

if you found a mefi 3 with a stock tune for a 502 mag and the correct harness that will couple to your engine harness your good to go,

The MEFI 1s work fine. If you are keeping the motor close to stock or even upping the horsepower (without boost) it will work fine. The biggest issue with MEFI 1 is its tuning fidelity. Having said that it is transparent to the end user.

PM me for my experience. Best of luck.

I would look for a set of take-off 496 exhaust manifolds in the swap shop. (Preferably aluminum). Usually about $500. Will bolt on and give you a small increase in power and eliminate the wet joint in the 502 exhaust. Will also nicely compliment any other upgrades