Timing Help Ford 428 Cobra Jet.

[Oldschool427]

1966 Ford 428 Stroked to 461. Stage II Edelbrock Heads, Jr Victor Manifold, 800 CFM Holley. Clay Smith Cam and Hyd flat tappid lifters, Roller rockers.
Timing set at 12 degrees. RPM tops out at 4800. Running 14 x 14 prop.

[Sleeper CP]

I'm not sure I understand your question and I would have just passed this post by, but anyone that runs a 461" FE grabs my interest ;)
Timing set at 12* initial ? Vacuum advance ? point's or electronic ? You may want to try locking it out at 32-34*. Oh, how much compression ?
Sleeper CP
Big Inch Ford Lover :D

[Oldschool427]

Electronic ing. 10.5.1 comp. vac. advance, yes. I'm just not getting top end?

[Sleeper CP]

So I don't lead you in the wrong direction there are a few guy's that post over at performanceboats.com that could more than likely answer your question.
Have you only timed it on the trailer ? And are you sure it's a timing issue ?
It just won't pull rpm's does it pop and spit, are you sure it has fuel pressure ?
Do you have any idea how much power it makes ?
Sleeper CP :D