a few years ago I decided I needed an old jet boat so I bought a 1974 Cee Bee Avenger project boat. I swore I was not going to spend any more than I had to. in the end I pieced together a junk 454 with all used parts and rebuilt the boat. the total engine cost was $800 and I had a total of $2400 in the entire boat. I ran the crap out of that motor for 2 years with it on the limit the whole time. most fun I ever had with a boat because it was fun and if the engine blew up I didnt care. seems the more you spend on them the more you stress over the money you spend on them.

It’s what we love. It’s what we do. Can’t take it with you anyway.

so I plugged both your ECMS in yesterday and pulled the tunes, they matched. They ARE modded but so little they would work with your current cam or stock as very little has been changed.
rev limiter was raised to 5400
5 to 7 degrees of timing was added at a dead idle from 200 rpms to 800,900, presumably to make it idle stronger but spark stabilization was untouched which does same thing if it needs it at idle for most part. Putting it in the map vs rpm will make it hunt less, would still work fine with stock cam.
2% fuel was pulled out of the last map vs rpm at 100 map in ONE box
no real fueling or timing changes were done anywhere aside from that 1 bpw vs rpm box that would change tune at all under a load, Smitty
Smitty

Thanks Smitty! So, I'll go back to stock cam in the port motor and if the Stbd motor has to come apart at any point I'll do the same.

In your opinion, would I be better off having you return the tunes to stock, or leave them as-is?

What about waking them up a little with some better cams and a little bit of Smitty’s knowhow to get you a good combination?

I could be talked into that if Smitty thinks a good result can be obtained without hands-on tuning.

Otherwise I'd just as soon stay stock and turn the key and go boating, yaknow?

Absolutely!!

If you have the valve springs to go 5400, Id leave it there, the timing at idle has been working for you and the 2% taken out of tune in last map cell vs rpm is virtually no different, that might have been a slight calibration difference from 1 year to another even, I just did the math, its more like 1.1%. You can always get some 02 readings if you change alot and tweak it a little, Smitty

Why would someone raise the limiter to 5400 on a pretty much stock 502 MPI its got to be running out of air and fuel around 5k

If i remember when a ton of us had stock 502mpi’s , 320yrs ago, the best speed rpm was 5000-5100 ….right ? I remember some touting 5050. Lol