I have a 66 with a 289 that ive done some mods to and was wondering what you guys would estimate im getting as far as HP. heres some of what ive done: Edelbrock 4v carb, edelbrock performer intake manifold, GT40p heads, MAC longtube headers, flowmaster duel exhaust, slightly higher rise cam than stock, cylinders are bored .30 over with pistons to fit them. i havnt had a chance to get to a dyno and was just wanted to see what you guys can guess, thanks

 

Try Desktop Dyno...google it, but I'd guesstimate around 250-275 hp.
DD will make you enter all engine info, especially the cam specs.

 

I would say around 270, maybe even more possibly.