Hey guys new to offshore only, in a bit of a problem . My 454 mag mpi literally exploded from a massive gasket failure. I came across a long block , 468ci, 10:1 compression, 502 cast heads , cam 114 234/236 diration. Using everything from the 454 mag on this long block . Yes it has more power but I don't know about the efi system . Will it work , can the injectors handled this engine uograde? Do I need to find a 502 ecm or flash the original. Really lost . Engine is in boat and put together , started it but went to Rev and it's gut less . Any help or recommendations will be of value. 25 baja outlaw

I would say that your manifold and cam are not a very good combo. The runners are too long for the rpm range that cam is going to want to run at. Plus, that cam is a little out there for the mefi1/3...mostly your idle will need work. You would have to find someone who really knows their stuff on tuning. It would be easiest just going back to something close to the factory cam.

Appreciate the feedback I do have a guy that is really good at tuning , we are actually do it tonight. So we will see what happens . Hold on to your hats
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Is he installing widebands?

By tuner I am assuming computer programmer ?

What exhaust do you have on it ?