Looking for some guidance
I'm currently swapping a 454 /330 with a carbureted 502 mag and both engines are out of the boat.
Would the addition of the efi kit in the add below be a good way to improve power and driveability?
One caveat is I plan on running stock manifolds and thru hull exhaust, would adding this conversion be a waste with stock exhaust and or would I risk reversion?

Thanks

p.s. I am envious of the the engine knowledge you guys have


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Anyone.

You will find many opinion's as to how well it will work. A basic efi system with a standard marine parts will get little performance benefit's from a efi system unless that is you do a very extensive upgrade. Aka OS sensor's to fine tune AFR's..that in turn would require exhaust headers...a very good backround in mapping or programing the efi it's self..injector duration's.. small change's in timing curves..I doubt very much if a very good tuner could get a 50hp increase out of a 500hp engine..i may be wrong but if properly carbed its highly unlikey.

If you were to go that far a good system would cost 5000 to only god know's...programming is not cheap and takes time skilled pro's are not zit popping comp nerd's. WIth that same investment one could turn that motor into a fire breathing dragon..With one caveat you will have to pump your throttle's to start the engine no turn key starting...a good execise actually it let's you know the state of the engine's tune every time you start her up.. Just a opinion however your milage may vary a tad.

Do you know what engine that EFI came off of ? MEFI ? is that an ASM throttle body ?

read "efi for everyone" might get some idea's and answers. long read tho.

Do yourself a favor and call Alex Haxby of Haxby Speed & Marine. He is the expert regarding quite a few things marine, Holley EFI being one. He is a very nice guy and his knowledge base and experience in the marine world is well known. An EFI system for what you are looking to do would be somewhere around $1,800-2,000. The new Holley TERMINATOR would be perfect. You don't need MPFI. But to be fair, ask Alex. He will set you up. Personally I can't stand carbs. Been there, done with that, never again!

FYI, with these new systems (HOLLEY EFI) you don't need a tuner for what you are doing. Yes there are adjustments that can be made via o2 readings and such, but for what you are doing the self learning ECM will be suffice. As another member recommended, read the "EFI for everyone" thread. Lots of great info.

+1 long read but welll worth the time