SPF Rear Ends

Bernica · #1 (**permalink**) 07-08-2005, 09:35 PM

SPF tells me that they now ship with a taller rear end. Somewhere around 3.30, which is what I am looking for. Has anyone else heard this? Also, the guy couldn't tell me who's rear end they were using, but definitely said that it was not a typical ford 8". This probably means I am looking at $$ to change ratios if I need to.

How have the SPF rear ends held up?

I am looking at buying one of their cars, but I have a strong 427mr (560hp) that won't need a 3.73 (unless I never want to see 1st or 2nd). Probably going with a toploader and vascillating over wide or close ratio now.

Thanks guys.

-Michael Bernica

xlr8or · #2 (**permalink**) 07-08-2005, 11:15 PM

They were using the standard Ford 8.8 rear with a 3.73 gear which is available from Ford Racing. Gear sets are under $200

Excaliber · #3 (**permalink**) 07-08-2005, 11:28 PM

Close ratio has a pretty high 1st gear compared to the wide ratio. I have a close ratio with a 3:31. 1st gear shift point is like 62 mph (26.5" tires at 6000 rpm). ERA suggests one might be happier with a wide ratio when running the TALL (3:31 is typical) rear gear set. I don't know, there are times when I kind of wish I had a lower 1st gear, there are times when I'm glad I have the higher 1st gear!

With about 500 horse I am STILL very "traction challenged" even WITH the high gear AND the sticky BIG letter Goodyears! I've never had a problem "taking off" from even a steep hill, etc. PLENTY torque! Man I LOVE IT when the 2, 3 and 4 shift come around like BAM, BAM, BAM, right up tight against each other! It's AWESOME the way the close ratio keeps the motor right in the power band. 85 into 3rd, 111-115 into 4th. WOW, I love my close ratio!

And with the taller rear gear set cruising aint so bad! SPF is onto something, no more "waste of time" 1st gear and starting out in 2nd for crying out loud!

Woodz428 · #4 (**permalink**) 07-09-2005, 07:00 AM

SPF is now using the Australian Dana rearend that they have installed in the Coupe. I believe it is a BTR(?), we have had no problems with ours and Dennis Olthoff has about 10,000+ miles on his (the Coupe) with no failures. He has subjected it to a large amount of HP and hard driving.

wtm442 · #5 (**permalink**) 07-09-2005, 07:42 AM

Check out this page for tons of automotive calculators
http://www.cobranet.com/calcs.htm

Check out the gearing calculator.

My SPF has 3.73 rear gears with the 3.27 first gear in Tremec 5 sp. The motor is a mild Oltoff 357W making 415 HP and will idle at 600 RPM. If I mash the pedal, sometimes it will go straight with lots of rubber. But sometimes it wants to swap ends.

Bought it used from original owner. I agree about the first gear being too much for general cruisin. When I slow down for something and I'm still rolling, I usually just shift into second and take off. I only put it in first when I'm stopped and want to make more noise, or accelerate to the speed limit in a more rapid manner

I have the 8.8 diff, and no problems in 6K miles. The new diff is supposed to be better, but what do I know ... I'm a newbie ... only had it for a year. I get so many questions about the car, I wrote up a "Car Show Handout". I keep a bunch in the trunk and use it as a memory check, or give them a copy if they ask for it. I've posted it in my pictures section.

There are a ton of other posts regarding gearing on CC. You might want to do a search.

decooney · #6 (**permalink**) 07-09-2005, 09:35 AM

Quote:

Originally posted by Excaliber

Close ratio has a pretty high 1st gear compared to the wide ratio. I have a close ratio with a 3:31. 1st gear shift point is like 62 mph (26.5" tires at 6000 rpm). ERA suggests one might be happier with a wide ratio when running the TALL (3:31 is typical) rear gear set. I don't know, there are times when I kind of wish I had a lower 1st gear, there are times when I'm glad I have the higher 1st gear!

I've tried both the wide and close ratio Toploaders with 3.31 axle ratios / FE powered. For slower take-offs and regular crusing about, I prefer the wide ratio trans with a lower first gear. However, its not great for quick take-offs as it results in easier tire spin for sure. For taking off like a slingshot, the extra tall gear in 1st with the close ratio trans is really nice. Now with my W/R toploader, I sometimes take off in 2nd gear just to try and simulate what it was like to have the C/R Toploader with my last setup. I agree, there are plus and minus' for both Wide/Close ratio TLs and I'd have a hard time trying to decide if I was doing it over again.

SFfiredog · #7 (**permalink**) 07-13-2005, 12:43 PM

Superformace switched to the Austrailan BTR center section when Ford stopped producing the 8.8 center sections.
the BTR gear ratio is 3.47 and will hold up fine.
--Mike

Cobrabill · #8 (**permalink**) 07-13-2005, 06:13 PM

I have 3.27 gears in my car and originally had a CR toploader.I had David Kee change it to a WR and it transformed the car.I wish he had the 2.87 cog around when i did it though.

3.73's with a 3.20-something first gear are useless.I pulled my rear gears before the motor even went in the car.
And i found 3.55's.Go figure.

shark · #9 (**permalink**) 07-17-2005, 07:53 PM

There's been qute a few of us whom have the "older" models that usually are equipped with the Tremec 3550 and rear gears of 3.73 to 1. Recently I and numerous others have switched out the trans for the newer Tremec TKO 600 and gone with the 3.27 gears. I'm using the TKO 600 with 3.31 polished gear set and use the 275/60/15 tires and also swap in on occasion a set of 17 inch wheels that sport 335/35/17 tires. The car is so much more driveable now. 1st gear is usable now and the gearing is spaced quite nicely. In the power band the car just continues to pull without no big 4th to 5th gear engine rpm drop/thud. If you're looking to buy a used SPF ask about the trans and gear setup. -- regards, Sharkey