Has anyone put headers on a stock 502 mag? If so, did you get any HP/speed gains? The mfg says 10 to 13% gain in HP, thats like 41 to 53 HP!! That seems like a ton.

Im also looking for info on blueprinting the hull on a 2000 Avenger, has anyone done that?? From what I have read that can give you an extra 2 or 3 MPH and that with headers, assuming you can get 10% HP gain, you should get another 2 or 3 MPH so if Im running 72 now shouldnt I be able to go 76 to 78 with thoes adds????

Please give me your thoughts.................

The blueprinting on a 2K bottom may get you 2 mph and the exhaust may get you 1 mph.

This is a guess but I think your figures are high.

Mine is a 98 modified hull with 550+hp per side and depending on what props I spin I can run up to 78 with my cruising props at 4850rpm to 80-82 with my lab props at 5300 rpm.

I would think that you would gain at least 2 - 3 MPH
Just loosing the 200 + LBS should gain you 1 MPH
People usually gain about 2 to 300 RPM

Powerquest 380 :
I put Stainless Marine Headers on my 99 Avengers in 2000 and pickup 4 mph. Like the poster above losting the extra weight is worth the time and effort. You cast iron headers weight 384 lbs for both motors. The Stainless Marine weight just about 100 lbs. The boat would do 68mph in stock and 72 after the headers were installed. I wasn't satifsed so I pur pro-chargers on them then. She became a rocket. Top out at 87 mph. Couldn't keep her in the water though as there was to much of the hull out of the water.
So the next best thing was change the motors to 500efi's and live with 82mph. Have turn key motors and am happy every time I launch her I also had the bottom blue printed. The factory cut 30" inches of the outside strake off to settle the bottom down into the bottom. This help to control her at high speeds. If you need anymore info e-mail me.
Blondes Preferred

John,
Don't listen to Scott, he doesn't even have a windshield, LOL!!!!!
can you hear me Scott ?!

Also, as Wildman1 mentioned after switching back to stock power:
" Have turn key motors and am happy every time I launch her"

I couldn't agree more!

Hope to see you on the water some more,
Paul

Come out of no where and attack me will ya

If you want more speed get rid of the windshield I gained 5 mph by getting rid of that huge gay piece of glass!!

BTW I was in Big Rapids yesterday should of hunted you down

OK Paul, what do you think headers will get me?? If the weight thing the others are talking about is correct and I get say 40 moer hp per eng.....
whats your guess???? And whos headers are the best?

Custom Marine Headers, Simply the best.

Custom Marine E-tops are the best. If you decide to go that way I have two sets of the Internal Sound choice tailpipes that I will make you a killer deal on if your interested.

Hey Orion 27Feaver, how much?? Have you had them installed on a motor or are they new and unused??