Thanks for all the responses I guess I am more confused I was told by the guy who rebuilt the motor was that headers were the way to go for more speed. But if I am only going to get 1 to 2 out of that forget it at the price I would have to spend. Any other suggestions? It does 70 mph right now and I am running a 850 speed demon carb on it just think with the horsepower it should go faster.

You need about 30hp to gain 2 mph on the top end. switching to headers over the SM's won't get you that. The SM's are more than adequate for at least 600hp.

i am run ss marine headers too. i made mine dry . i now 540dart 650hp i had them 20years and i happy with them!!!

you say you are doing 70mph at wt rpm ???? the rigth prop makes a big change in the speed! i no when i started out testing prop i got 72 to 75 4900rpm now i am over 80mph+ at 5500rpm ! you need to no the peak rpm your motor truns.i beleave it is 1000rpm added to the highes tq .

It is doing 70 mph at 5100 rpm that is fully trimmed.I am running a 4 bladed 25 pitch merc.

It's tough to get a lot of speed out of the 260. Search through the Powerquest threads and you will see what others have done with larger HP. The hull is not as fast as most other boats of the same size.

try a 25 mirage prop not a plus the old mirage prop i bet you will get better speed 4 blades are slower !! i run the mirage that the best . did you dyno the motor??? if so let see the sheet????? if not try a 25mirage i did 4 blade on my boat it was slower 3 blade the best!!!! good luck