Rear gear set for Drag Week

[KjcfeF100]

Question for Jay and other "Drag Week" type car owners.  Jay I know you're so busy trying to get the car ready for drag week that you may not be able to respond to this any time soon (I don't know how you can do half of what is in your schedule); but was curious if you chose to use Pro/Drag rear diff. gears on your Galaxie and Shelby clone?  And what about the Mach 1? I know quite a few of the Drag Week heavy hitters are having good luck keeping the Pro gears in good condition for thousands of miles of street use.

[jayb]

I've read about using pro gears on the street also, but I've never done it.  I've always just used the normal Richmond street gears.  I don't launch my car on the trans brake, I just foot brake it to be a little easier on the drivetrain, so I've had no trouble so far with the normal street gears on any of my cars.  Hopefully I didn't just jinx myself by saying that 

[machoneman]

No Drag Week participant here but....see what Mark Williams says about Richmond's street versus race gears

http://www.markwilliams.com/ringpin.aspx

I've run both over the years (mainly Richmond) but would not hesitate to run the softer race gears in a car that will see occasional to moderate drag use. What really makes a difference is someone with a heavy car, stick, lots of hp, lots of slick and a dump-the-clutch launch at WOT. The lack of a trans brake and the somewhat forgiving nature of an auto trans has helped Jay a bunch, I'm sure.  Btw, the 'softer' material in race gears has only marginally lower Rockwell numbers and the material spec is pretty close too....it's not that much different than street gears.

[KjcfeF100]

Thanks for the replies.  I certainly don't have lots of HP by modern standards, but trying to decide between street and Pro gears for my next gear set.  It's for my 68 F100 that comes in just under 4000 lbs. with me in it, 5 speed manual, big slicks, and I'm trying to get it hooked up or close to hooked up.  My 482 is supposed to be in the neighborhood of 650 HP, but I think I may be a little shy of that, so far only mid 12's at 114 mph, should go mid 11's if I could get some decent 60 foot times.  So far I haven't tried any high rpm launches, waiting till I have a slipper type clutch and my new lower gears before I try that.  Only sees limited street use and normally no long drives, haven't been over 30 miles at one time in who knows when.  I've had street gears recommended, and also pro gears; looks like I'm stuck in the middle and that either choice is somewhat of a compromise. 

[jayb]

My Galaxie weighs 3935 with me in it, and ran 9.50s with the street gears.  Unless you are going to shock the driveline with a trans brake or dumping the clutch, I think the street gears would work just fine for you.

Another alternative that I've heard about, but don't really know much about, are NASCAR 9" gears.  These kind of sound like the best of both worlds; supposedly they are strong enough for extreme drag strip use, but of course due to the length of NASCAR races they have to be durable as well.  Anybody know anything about those?  You see them for sale fairly regularly in the FE Forum classifieds and on ebay.

[DEANs427]

I bought one of those nascar gearsets with a spool off ebay this spring and have been running it all summer without a problem, it was a great deal using the 'best offer' bid

[machoneman]

I'd buy a used NASCAR gearset next time around. But, I'll note there are two kinds generally available. One looks like a std. gearset and may/may not have all outer surfaces polished.

The other has a heavily modified ring gear that has the backside profiled milled & swiss-cheesed, so to speak, and ring gear bolt bosses have been scalloped to save weight and reduce inertia. I don't think this type of gearset would be useful to a drag racer where more mass equals more strength.  

Here's a pic of a scalloped gear. Not that easy to see but blow up the pic about 150% and it becomes much more obvious. Amazing too one can buy a whole 9" center for just under $500! 

http://www.rcrdriveline.com/6raniinfoces.html