engine cutting out please help

[HBboat]

hello I'm new on here. I need some direction.. I have just installed a short block 5.0gm GXI-E engine in a 2005 auzra deck boat. Yes I took a truck 305 vortec put new rod and main bearings honed it installed new rings and installed the factory marine cam. I used the heads off of the original boat engine because it only had 100 hours on it .. they didn't winterize it and the original block cracked.. anyways everything is together and running . oil psi good starts good accelerates fine but when your at a steady rpm anything after 3200 up to 4800 its cuts out spits sputters kind of like a misfire it will do it on the water or in neutral on the trailer. Installed new thermostat different cap new spark plugs, distributer is installed correctly. I have moved the distributor around if I retard the timing it starts cutting out at 2000 rpm if I advance the timing it starts cutting our after 3200. what would be the proper readings in ohms to test the computer temp sensor.. I'm wondering if its running rich.. what is the symptoms of the black paint chips in the fuel system I did find some on the screen of the fuel psi regulator. fuel psi on the rail is 50lbs haven't been able to test low side because I don't have the correct adaptor. but it is pumping and has some pressure when I push in the Schrader valve.... I am stumped and this guy is wanting his boat back asap. its almost like it is hitting the rpm limit of a rev limiter but it will continue to climb up in rpm cutting out the entire time .

 

[alldodge]

Old motor ran fine with no issues
New motor has high rpm misfire
Adjusting timing moves misfire between 2000 to 3200

Does fuel pressure stay at 50 psi when mis starts? (Pressure should be 50 to 60 psi)

Misfire can be caused by the MAP and CPS.
Inaccurate MAP will cause incorrect injector pulse (lean/rich).
Used a truck motor block, was it the same year as the original? If the reluctor end play is excessive, or incorrect reluctor was used with CPS.

Has the motor been scanned for codes?

 

[HBboat]

Old motor ran fine with no issues
New motor has high rpm misfire
Adjusting timing moves misfire between 2000 to 3200

Does fuel pressure stay at 50 psi when mis starts? (Pressure should be 50 to 60 psi)

Misfire can be caused by the MAP and CPS.
Inaccurate MAP will cause incorrect injector pulse (lean/rich).
Used a truck motor block, was it the same year as the original? If the reluctor end play is excessive, or incorrect reluctor was used with CPS.

Has the motor been scanned for codes?

idk if original motor ran ok or not. boat was never driven by this owner. he purchased it with busted block and he nor i never heard it run. motor has not been scanned i have no way to do so . i have a snapon scan tool but i have not found any way to use it for the marine stuff. i need to retest fuel psi but im pretty sure it stays 50 psi. cps is new and i used the reluctor out of the original marine engine

 

[alldodge]

have a snapon scan tool but i have not found any way to use it for the marine stuff

Correct, have to have marine scan tool
Rinda.com

The main problem with the MPI motors is its next to impossible to find out what is wrong with them without a scanner. Might stumble upon the issue by replacing more parts, but this can also cause other issues

Attached are 2 bulletins

 

[HBboat]

figured it out ... even though i put dist back in what i had marked as correct location . it was a tooth out.. advanced it one tooth and it runs perfect now.. thanks for all your ideas.