Timing might be a bit too much. What are your plugs looking like? I'm running 33* on my 466 that just dyno'd in the 630hp range with 12:1 and ported d0ve's.
As for your tranny. Make sure the clutches and band are in good shape 1st. Then pull the vavle body. If you can't afford a good complete vb, then put in a Transgo stage II kit. It'll give you holding in 1st and 2nd but will shift normal (actually much firmer) in drive. There are a few other tricks by changing out the servo and apply lever as well that will help out. Just remember as the hp and tqe numbers go up on the motor, the tranny needs to be upgradded to match.
As for your tranny. Make sure the clutches and band are in good shape 1st. Then pull the vavle body. If you can't afford a good complete vb, then put in a Transgo stage II kit. It'll give you holding in 1st and 2nd but will shift normal (actually much firmer) in drive. There are a few other tricks by changing out the servo and apply lever as well that will help out. Just remember as the hp and tqe numbers go up on the motor, the tranny needs to be upgradded to match.