5.7 stumbles after 4200 rpm

[flipbro]

Well I splashed my boat to day after the new engine swap. Vortec heads on a 1990 remam with doul plane intake with a mild rv cam 423 444 with my original quadro jet carb that was rebuilt last year. It runs great rite to 4200 rpms. I still have about 1 inch of throttle to go but if I open it up full it startes to stumble. The water fuel sseparator is new. Any body got any starting points? Does it sound fuel related or timing related?

 

[Scott Danforth]

this is where you went from 5.0 to 5.7 if memory serves. did you recalibrate the carb for the larger motor?

 

[flipbro]

Nope. Always 5.7 run good on the last engine..

 

[flipbro]

Would the valves floating cause this sympton? I did reuse the original springs from the vortecs. They have about 95 to 100 pounds preaaure is that enough?

 

[Bondo]

Ayuh,..... Sure sounds like a fuel delivery issue,..... also hard to believe the valves are floatin',.....

Check the contents of that new fuel filter,......

 

[flipbro]

Yes I agree on it sure seems like a fuel issue.I couldnt see the valves floating either with such a mild cam.. Just thought I pick some brains. I will definitely check out my filters contents