Does an Imco Extreme Advantage 1998 year drive have straight cut XR gears or spiral Bravo 1 type gears?
How does it compare for strength over a standard XR?

The IMCO gears are straight cut and a little bigger aswell as the clutch and bearings.

I will let you know about the strength. I blew one of my bravo 1 uppers and got the old style imco. I am running over 700hp per so we will see

It would be strange if they used the Bravo 1 gears but maybe the XR wasn't out yet.

I believe they are Bravo style gears with thickened floors like the x drives have.

In 98, I dont believe the thick floored gears or the XR gears were out yet. It is possible it has the Imco modified thin floor gears.. They welded the floor and bead blasted and reheat treated them.. The X gears are a better gear, but they all have the same helical cut teeth..
Correct me if I am wrong, but I think all the X stuff came out in 2000?

Im not exactly sure when the x stuff came out (I want to say 2001) but I can tell you that as Dick says,a 1998 imco is going to have the old thin floored gears that are maybe welded up then then ground back down as that was the best you could get in the 90's in a bravo,Smitty

Hi Dick.Lowers are going just great.Next race 5 weeks away.So the 98 Imco isn't going to be a real strong upper thats comparable to an XR?Thanks for your reply Smitty.

I have the IMCO extreme's with the ibeam cases. They break. Just XR gears. I'm sure they are newer than what you are looking at.
I think the problem is with the gears in general. Personally, I think the material is not the best & no matter how strong the case, the gear is the problem.
Someone needs to build a "real" gear with "real" materials.

According to the experts the later XR gears are much weaker than they use to be.Easy up and real easy down isn't working.I just recently tore a tooth that destroyed a new upper unit.
Dick who posted previously feels the new IMCO scx is the way to go.Just hard to get around the initial $.
Thats the way i'm headed though.