Steel caps for 8.75" Mopars???

bill dedman · 06-07-2009, 10:10 PM

I have a bracket car that has a Vortech-blown 360 Magnum, and I am wanting to build a third member for its 8.75" rear end that will have a reasonable life-span.

I have no transbrake, nor high stall converter (it stalls about 2,500 rpm) and the ring and pinon are 4.10:1 ratio.

The tires will be 9"-wide M-T bias-ply slicks (no d.o.t. tires or drag radials) and will be 28"-tall.

I plan on leaving at about 2,000 rpm, if the brakes will hold it still. (Less, if they won't/can't.)

The engine was tested on a chassis dyno @ 477 ft. pounds of rear wheel torque (445 rear wheel hp) at 10 pounds of boost. Abundant low-end torque....

It will hopefully, be capable of some low 1.70 60-foot times, maybe better, but not counting on it.

I have a NEWLY BUILT 489-case center-section (with a crush sleeve eliminator kit installed) that has a cone-type limited-slip unit (this is a street/strip car), with the larger, (7290) u-joint yoke.

I am wondering if I might need to install a steel carrier-bearing back support (CAP) in place of the cast iron one that it comes with (OEM.)

I don't want to have to do this if it's overkill. The car weighs 3,600 pounds and should run mid-11's if it hooks (118 mph.)

I'd appreciate some advice on this from people who have experience with the 8.75" in a moderately powerful 3,600-pound car like mine. {That's 3,600 pounds with me in it, ready-to-race weight.)

Like I said, this is not something I want to do unless it's actually necessary. Do these 8.75" units break that bearing cap in the kind of useage I described? I will only race it occasionally.

Thanks for any information... it will be much appreciated.

Bill

06-07-2009, 10:10 PM	#1
bill dedman VIP Member Join Date: Feb 2002 Location: Conway, AR Posts: 1,739 Likes: 0 Liked 6 Times in 4 Posts	Steel caps for 8.75" Mopars??? I have a bracket car that has a Vortech-blown 360 Magnum, and I am wanting to build a third member for its 8.75" rear end that will have a reasonable life-span. I have no transbrake, nor high stall converter (it stalls about 2,500 rpm) and the ring and pinon are 4.10:1 ratio. The tires will be 9"-wide M-T bias-ply slicks (no d.o.t. tires or drag radials) and will be 28"-tall. I plan on leaving at about 2,000 rpm, if the brakes will hold it still. (Less, if they won't/can't.) The engine was tested on a chassis dyno @ 477 ft. pounds of rear wheel torque (445 rear wheel hp) at 10 pounds of boost. Abundant low-end torque.... It will hopefully, be capable of some low 1.70 60-foot times, maybe better, but not counting on it. I have a NEWLY BUILT 489-case center-section (with a crush sleeve eliminator kit installed) that has a cone-type limited-slip unit (this is a street/strip car), with the larger, (7290) u-joint yoke. I am wondering if I might need to install a steel carrier-bearing back support (CAP) in place of the cast iron one that it comes with (OEM.) I don't want to have to do this if it's overkill. The car weighs 3,600 pounds and should run mid-11's if it hooks (118 mph.) I'd appreciate some advice on this from people who have experience with the 8.75" in a moderately powerful 3,600-pound car like mine. {That's 3,600 pounds with me in it, ready-to-race weight.) Like I said, this is not something I want to do unless it's actually necessary. Do these 8.75" units break that bearing cap in the kind of useage I described? I will only race it occasionally. Thanks for any information... it will be much appreciated. Bill __________________ Bill Last edited by bill dedman; 06-07-2009 at 11:17 PM.