cut down Ford 9" ring gear to 8.5" strength?

[JavmanBBG]

Looking at used and new REM finished Nascar gears and was finding many gear sets have the ring gear turned down to 8.5 as well as back cutting and scalloping between the bolt holes. The back cut in and such don't bother me but how much strength is lost due to the smaller contact area of a turned down 8.5 ring gear and is there is any special setup required.

Also, any recommended options for a 10 bolt pinion support to adapt an aluminum center built for pro gears to the smaller standard pinion

Thanks

[andrewb70]

What exactly are you trying to do?

If you have a Gm 10 bolt, the ford 9" gears aren't going to work...

Andrew

[JavmanBBG]

I have an AMX that has been caged for road racing and it came with a big bearing 9" from an AMX that was being restored from a drag car that has then correct dimensions and an old Lenco bolt through aluminum center with a very large 10 bolt pinion support setup with the larger pinion pro gears and 35 spline axels. I would like to convert it to be used with a wavetrac or such and 3.15-3.45 gears. Looking at the Gleason NASCAR gears as they seem to be top shelf product. Also already have an Emco 44t 4 speed and 401 for the project. Plan on 650-700 HP with a supercharger.

[Nothingface5384]

if you have a 9inch forget the wavetrac and look into either S-trac or DPI Platnium track

[Ron Sutton]

The gears from NASCAR teams that have the outside radius cut down 1/4" so the OD is 8.5" are for super speedway tracks like Daytona & Talladega. Combine that with how the car is used ... steady state in 4th gear ... only shifting is in & out of the pits ... and you can see why teams are willing to give up some strength for reduced power loss.

IMHO, these gear sets would work fine for most street applications with low to moderate power. For applications where power exceeds 550HP and/or will be driven hard on road courses, I'd pass on these and go for full size gears.

:cheers:

[JavmanBBG]

Thanks that is what I was after. I will look for full size gears. Since they where outlawed last year I think maybe there will be a better selection after this season.

[HarleyR]

Pretty much every ring and pinion has had extensive work done to lighten it up regardless of ratio... The older ratios in the 3.00's aren't legal anymore due to the ratio requirements at all tracks...I'd stay away from them simply because they have the tendency to shear the pinion because the huge diameter of the pinion teeth.... Broken gears at Daytona and talladega leaving pit road were pretty common