CMI vs Gill
 

I am planning on upgrading my power and am wondering for a stock merc 500hp the HP diff you will see with cmi vs gill
didnt the 500hp come strock with gills?

Klaw,

The HP 500 carbed use the Gills. The HP 500 EFIs uses CMI. Same HP rating for both even though I have been told the EFIs will dyno with more HP than the carbed. The EFIs also use a different cam grind which is a little more aggressive than the cam used in the carbed version.

Hope this helps.

Be safe,
Mark

The motors I am looking at are carbed with 200 hours on them
I guess the biggest diff is the look factor of o tube exhaust manifod versus teh gil type thanks alot guys

Klaw, Go with the CMI's they sound better and look better.
Just my .02

Mark

Yes, the Merc HP500 came with the GIL exhausts, and the CMI's will give you maybe about 20hp over the GIL's. You may not feel it that much in the boat---maybe a little bit of a kick.

I jsust need to find a couple of used sets the motors are taking most of the budget along with the new interior

Try looking at this chart. HP between them all is close but the tube headers (CMIs) and the Eickerts seem to provide substantially more torque than the manifold styles.
http://www.arizonahotboats.com/exhaustdyno.xls

Go with the CMI's. You will thank yoursefl the next time you change spark lpugs.

Team Gary, That is definately a FOR SURE! It's like you need another thumb where your hand and wrist are joined together! Either that or you need to cut all your fingers off except for your index finger and thumb!

Canada Jeff, how is exceleration let's say from 3000rpm to WOT between you and your friend's boat?

Cmi's look alot better but the gill's last alot longer. From what I hear Cmi has a tendancy to crack and cmi is a little funny with thier warrenty.