SB I believe that was for the 1994-95 350 Mag/EFI motor. The 320 had a front mounted TB. 94-95 motors had the same progressive side mount two stage TB the 454/502 Mag/EFI motors did. Lingenfelter worked on it with Merc for the 94-95 era motors but can't attest if he did collaboration with the 320 motor.

Concur. Said another way if the 320 motor needed a 26 lb/hr injector, and you got some other brand that said it was a 26 lb/hr injector, but actually flowed higher/lower then the motor would unknowingly be richer or leaner than designed. The lean side is the problem. By flowing the injectors BUP and you will know WHAT the motor was designed for and select an appropriate replacement injector.

Merc has used all sorts of injectors from the Bosch to Kehein (effectively Honda) injectors. Many of their injector part numbers don't cross reference thus anchoring Mercs monopolization of their systems. It can be a PITA when sourcing injectors. I actually took my manifiold, rail and injectors up to RC injection to flow test, compare and fit new injectors and do an A/B comparison between stock and aftermarket. Took time but was worth it.

BUPs advice is spot on and I'd follow it.

well this is a new setup for me, I still have my 88 242 ss bravo w/ 7.4 with cam, heads, tuned exhaust and high rise intake intake, around 420 hp 60mph.
The 320 EFI's in my 88 272 are factory mercruiser racing before they went blue color, 320 HP at 5200-5400 rpm, the set up is a 4 bolt main block, forged crank and rods, bigger cam and roller tip rockers and tunnel ram batch multiport fuel injection. Alot different than the 260 hp version.
My camp is in Naples by the way.

I knew the bottom end was forged/4 bolt etc, but didn't know the heads were different. I always thought that motor and the 300 tempest were cool, but are so rare. I may make it to Sebago with my boat this summer.

Dug up old file! Injectors are Bosch 0280150706 same as 85/86 4.7l Porsche 928.

Heads on mine are World S/R Torquer unsure if they are original

Hey Sonicss, Thank you very much I appreciate your help, and everyone elses too!
Jim

O2 = closed loop.

Jeff

The 320 EFI does in fact make 320 hp at the crank with marine exhaust. It also runs at about 11:1 A/F at full load so there is some power to be made there.
The heads are nothing special, same as a 260 head. Something you would find in a TPI Camaro.

It's a good durable package.


Jeff

11;1 is mad rich. why would they do that?