Headers
 

I am looking for Headers for my 260 powerquest. It had a 502 but upgraded to a 509 merc carb motor. I have stainless steel marine exhaust on there now but looking for more speed. Used or new or any advise would be helpful.

West Coast Marine Superstore in the classifieds has some smokin deals
good luck

I dont think that going from stainless marine exhaust to any header is going to get you more speed from a 509 alone. Maybe if you had a 598 or a 632 the stailless setup might be limiting, but not likely with a 509. Just my opinion, I am sure others with more knowledge will chime in.

+1 not going to get a good ROI going to headers.

(unless you have a fully ported super cammed titanium valve high compression monster...) and even then not much.

UD

+2 You won't see any gains going from SM exhaust to CMI's or Stellings headers.

+3, Stainless marine exhaust is fine for what you have hp wise. No gain and big $ to switch to a header style exhaust system unless your planning on bumping up the hp with more engine mods. Stainless shoould be good up to 6-650 hp. My 2ct's.

+4 stainless marine is good up to 800 to 900 hp thats gen 2 gen 3 unlimited hp and will out last any header by 10yrs on the market.

if you want more speed talk to DEAN GELLNER ENGEERING, they hand port intakes and have a custom carb set up that you would see a different with and if you let him send a cam to match its like a extra 10mph over most 509s, mine was 647hp before the carb change after just the carb change I picked up 4mph,670hp will do the cam and intake this winter on my back up motor which is the 509 that will get me to 700 to 725, main motor is a 572 blower that was built by him.

A set of big tubed headers will only slow it down. Bigger is not alway's better. :eek:

I run stainless marine headers, work well, running a 509 as well, they are not big tube units...Rob

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:drink: 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