I've read just about everything on converting from differing Mefi units. I'm having issues with my engine and I'm almost to the point of converting. I have a Mefi 1 but have a spare 4b ecu laying around.

I'm not new to repinning wiring harnesses but I have found very little in detail of the conversion. I have both ecu pinout diagrams and they appear really similar. The biggest thing I know to be different is the Mefi 4 has a crank angle sensor vs the sensor in the distributor like the Mefi 1. But I believe the Mefi 4 also sends a signal from the distributor. Who should I call or contact for a 5 minute phone call to solve my questions?

Give me a few to get to my office and I'll send you the service manual. Should have everything you need as far as pin placement

Thanks. I think I have everything. The main thing is do I need the CAS for the mefi 4 ecu to operate correctly.

No, I have mefi 4's on several motors without crank angle sensor, Smitty

Thanks. I thought for sure it would throw a code for no signal from the sensor. I thought it would need the CAS deleted from the programming.

its all in how the ecu's program is configured.I've used the 4b on the 496's w/ crank and cam and also on my hei engines were it only has a 6 pin distributor.I could,if I wanted to set it up for dis set up and I believe it will work w/ 24,58 tooth crank trigger set ups.

the complete 4 family support 7x 24x and 58x or 60-2

I've been searching OSO for quite awhile now. Is there any advantages to a LT4 hot cam on a mefi 1 system? I've found a ton of info on cars/trucks and boats with carbs. Virtually nothing speakable on boat EFI.

I've been following your other thread regarding your engine performance. The problems you are having have nothing to do with the series of MEFI computer

Much appreciated. I've been milling around the jet boat forums and it seems that my engine is right on par with others. I believe my friends low hour 350 was a factory freak or his tach was off. It's fairly hard to find a 2.9 impeller used. That's my next step.
Don't forget my fuel burn is something fierce. So I'm still sorting through that issue.