L29 head 454 MEFI tune

[roughneck427]

took my flat bottom boat out with the stock tune and only 13-16 degrees of timing it turned only 4000rpm then bumped it up to 21-25 in WOT area and picked up some rpm to 4500 rpm whats a safe rule of thumb on the L29 heads?? I know regular bbc heads like 36 degrees or so the engine only runs at 160 degrees