please state your 1/4 mile times!
Any official GM data how much abuse they take?

 

When I was still using one, I ran high 11's at 117 mph on 26" tall slicks and 3.27 gears.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
Best MPH on a time slip: 119.42 altitude corrected to 124.86
Altitude corrected rear wheel HP: 493
Best 60 foot: 1.586

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

Stephen, when you say when I had one you worry me You didn't blow it up did ya?

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'86 Iroc ZZ4
Best Run 13.8 @ 100mph

 

I've been running 1.7x at 12.1x with no problems (3.27 ratio). I recently installed a 3.73 ratio and may even try a 4.10 in one of my 9 bolts to see how works. Just don't use a trans brake or a manual trans (with slicks) and it should work well into the 11's.

Miles

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88 427 Camaro
12.18 @ 113mph 1.75 60ft
Currently installing 3.73's into my 9 bolt (YES, it is a 9 bolt & YES they are 3.73's, not 3.70. I currently have 4.10 gear sets and new series 3 carriers in stock for 9 bolts )
www.koolmeister.com

 

Notice both of these gentlemen run big blocks which are more violent (TORQUE) than small blocks

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92Z28
89GTA

 

I never used mine with the big block. I was running a very strong 383 that blew up last year. I changed the diff just before the SBC blew up. There was nothing wrong with it. I even still have the complete 9 bolt diff with disk brakes sitting in my shed. The reason I changed it is the lack of performance parts at the time for the 9 bolt. I needed some good aftermarket axles. I wanted a solid diff cover to add strength. And mainly I needed deeper gears. My current 10 bolt has 4.10 gears and this winter a ford 9" goes in with 4.56 gears with a spool.

Those high 11's at 117 mph were with the 3.27 geared 9 bolt on 26" slicks. I was pulling 1.7's 60 foot times. The combination I was running either needed 3.90 gears (no such luck) or going to 28" tall tires and 4.10 gears which I did with the diff swap. That way I was topped out at the red line at the end of the 1/4 mile. With the old combination by the time I hit the end of the 1/4 mile I was only doing about 5500 rpm but was shifting at 6500. There was more in the engine but gearing was my limiting factor. Unfortunatly I never did get to see what the potential of the 383 was since it blew up before I was able to get a good full pass with the new diff. The diff and new gearing wasn't the cause. I threw a rod and disintigrated a piston. Only the heads and intake were salvagable.

 

i had a 9-bolt with 3.45 gears until i broke one of the teeth off the pinion gear still driveable noisy as hell tho, so far i have only heard about the gears being weak. when i get some money together i am going to put some 3.73`s or 3.70 in it, but so far the 10-bolt is doing fine.good thing i had an extra rear...

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87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
Dynomax catback w/custom tips
K&N oil filter,Mobil 1 synth, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims ,

400 sbc and a 6 spd in the works