On the late 454 truck, and in the boats with the big block TBI, they used 4.3 injectors. Surprised the 4.3L injectors let you get that far.Apparently, that's how GM did it. Sorry for the muddy lake water, this is a small lake close to my house. Or, I may have to do some major fuel system upgrades. Since the injectors on the boat are 4.3 injectors, ran at a higher fuel pressure, maybe a good set on 60 pound injectors (from a 350) would do the trick. I am running the stock injectors, my junkyard 60 pound injectors were junk, wouldn't even pulse. Which the compression in this motor should be up around 10-10.5:1, being that I put flat top piston in it. Hard starting with 8 degrees initial timing.The good news is, I am not getting any knock under load at all until it starts to lean out up top. I know I am not in fuel cut off, becasue I have that set to 5500 RPM, and its not setting the fuel RPM cut off flag in the scanner. I also start picking up some spark knock. I am running around 12.5 AFR across the board until the boat hits 5000 RPM and the AFR climbs to the mid 13's and the wide band starts to fluctuate. I started bumping the BPW table up until I hit 12.5 at 3000 RPM then worked my way up in 500 RPM increments and made fuel adjustments as needed. With the stock BPW table I was running around 14.1 AFR with just an easy cruise at about 3000 RPM. Then add the timing back in to the main spark table. I may have to change this in the tune, maybe back it off to 5 degrees or so and reset the distributor.
It was cranking kind of hard, like an old carb motor with the timing set too high.
Till it hits around 5000 RPM, then the fuel injectors max out.
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