Imco SC Extreme vs. Bravo XR
 

Is the Imco SC Extreme comparable to a Bravo XR?........prop shaft diameter the same?.....what is the horsepower rating on the Imco?

very much the same. uses the same gears. the leading edge of the lower differs in appearance and the skeg is smaller aswell compared to the merc sportmaster lower,.

I wonder what lower is more hydrodynamically advanced. Not sure if that a word but you know what I mean.

Can the skeg on the sportmaster be redused in size and is there any benifit or speed increase?

I wouldnt do that on mine I am currently going to a 2inch shorter and I want the longer skeg for better steering at high speeds. I noticed even with my regular bravo drive over 100 mph steering was getting a little loose. I have heard of alot of guys adding length to their imco skags also. I had a choice between the sportmaster and imco and my drive builder recomended the sportmaster.

The SC drive is an XR with much stouter case. There are a few parts that are Imco upgrades, but for the most part the weak point is the gears themselves. Of course depending on power level. At 100mph, it sounds like you are in that league.
I have compared pricing on the sportmaster and the imco and there is about, if I remember correctly, $2k difference, sportmaster being the high dollar unit. That is when I build an Imco (using Merc bearing carrier and propshaft), vers buiding a Sportmaster. I have no experience with the Sportmaster, but the Imco shorty is a proven piece. I recommend the Imco to my customers, unless they want otherwise.

Hope this helps.
Dick

My drive builder use to work for imco for like 7 years. He recommended the sportmaster lower because he said it has a stouter and thicker case and skag. I have been in my buddies 33 foot eliminator daytona I nick named "deathtrap" @ over 140mph @6000 rpm with imco extreme sc 1.25gears and 36 pitch props. With engines I built making over 1100 hp @ 6500rpm and over 1000 pounds of torque at less than 4000 rpm. Hes blown up 4 drives in less than 2 years I finally had to lower the boost. The boat still runs 130mph with 3 pounds of boost without retuning it. He should of bought #6 drives dumba$$ 160+ mph boat easy if the drives would hold.

Hey Brent,
Don"t mean to hijack your thread, but I did experiance a loss of speed when I changed from standard xr to sportmaster lower. It was worth the trade off for better reliability. Cases were cracking on the standard lower xr at top of retainer ring threads. I was just curious to know could I get the 3-5 mph difference back with some modifications. Thanks Gary

Maybe a bit off topic, but has anyone heard anything about Imcos new SCX drives and how they hold up?

I read a sevice bulliten from mercury that the sportmaster lower drives were specifically designed for boat that go over 80-90 mph. It also said that if it is use in other slower applications it would actually slow the boat down.