It's not a huge difference but from what I've been reading you could get a 500 efi intake and run holley injection? You can get 550 out of that intake from what I've read....just a thought?

As a old school guy I love these, but how do they perform against something like the XT system? Has anyone did a back to back dyno test of this type of intake compared to a single plane, or XT?

I was going to run a 525 intake but I was told it has special injectors so I bailed plus the guy I was buying it from was jerking me around. I just want SIMPLE, im not looking to stop the world with this thing just want some fun reliable power. I know (fun, reliable & boat) do not belong in the same sentence!! Im thinking the XT with Holley HP would be a kick ass setup but now the TB clearance issue on the stat housing and the manufacture lead-time nonsense can be an issue.

Speedway motors says it ships by 11/29/22 but I am going to call and see how realistic that is or if it is total BS to get the hook set then drag you through the water of WAITING for months on end. Winter is long but not that long!!
I curious how I will adapt the throttle linkage to the Edelbrock cable style TB linkage??

I think you have the 525 efi injectors mistaken for the 500efi injectors.

Don't get hung up on the injectors, you will need to buy some and tune it anyway.

As an fyi: Edelbrock got bought out not too long ao. Same company that bought out CompCams. There's some useless facts for the day.
Actually maybe not that useless, as I don't think Edelbrock does all, or much, of their own castings in house now because of this.

So before going through all the trouble of swapping intakes, how bad is the stock MPI? Are they really as restrictive has I have been told, is it really worth swapping it out? Again im not looking to make a 75mph boat here I just want a fun lake boat that works well and decently performs. Best I ever saw out of this thing was 62mph once, it would normally run around 58-60 at WOT and cruise around 38mph at 3,500rpm. I knew something wasn't right as it began dropping off MPH was decently and when I opened it I found the below:

Parts suck to get now so I don't want to make this more complicated than it needs to be, I want my boat back in the water by Memorial day, engine was dropped off to the machine shop Friday. It was running on a MEFI-1 which is believe is garbage so swapping to holley is a MUST. I was thinking of going dry exhaust and a HOT cam but thats all out the window, I just want it to sound good, fire every time and enjoy being on the water!

Looks like someone replaced one head gasket when they shoulda done both.

Don't give up on the MPI intake, it can actually support more HP than the 500/525 style. MPI will make more torque than anything on the market but won't go much past 5600 rpm for peak power. Articfriends(Smitty) is now enlarging these stock throttle bodies and that does make a pretty good bolt-on difference. Also let him school you on the flame arrestors, that plastic one you have is absolutely terrible and kills HP. He has made over 700 hp with a low CR 548 with a modified MPI intake.

Also, you probably have MEFI3? I'd just stick with that and save a couple grand versus going with Holley. It can be re-tuned and is more than capable for your plans.

One big thing if you like to run at high RPM for extended periods of time, the factory oil system sucks and kills oil PSI. Change block adapter, filter head, cooler, and go to -10 lines at a minimum and you will see another 20 psi oil pressure with no other changes. Couldn't believe the difference on mine, I was about to rebuild them for being tired as hot oil psi was getting close to 32 psi max, now it doesn't go below 50 psi.

Probably does have MEFI-1 judging by V-belts rather than Serpentine...

Edit: I can see the ECM in one pic, it's a MEFI-1