New powertrain, do I need a back brace?

[69dodge383]

I got a new powertrain for my 69 charger

1972 440HP bored .030
Hughes Solid Lifter Cam 277/283 ADV 245/250@.050 LIFT 560/575 LSA 108
Edelbrock Performer RPM, hughes ported
Domed pistons apx. 10:5 to 1 compression
Victor Hi Rise Intake
Demon 850 Carb
9 1/2" Dynamic Converter
727 Trans
4.10 Rear Gear
28" Tall Tire
Motor output 550 to 600HP

*May add NOS 100-250

Do I need a backbrace on the 8 3/4 sure grip?

Thanks,

Doug

[Cooter]

You didn't mention if you were looking to run a 28" tall slick or not. I have been "soft" launching a 505 Stroker on a 200 Shot with an 8 3/4 rear that is narrowed, but otherwise stock, on DOT's. I DO NOT Bomb 650 Ft Lbs out the hole though. If you are dead hooking, a back brace may not help that ring and pinion/axles.

Is the 8 3/4 rear stock? Axles?

[69dodge383]

I will be on 28" tall street tires most of the time. I will probably go to the track maybe once a year. When I go to the track I will probably throw on some MT or Hoosier Drag radials.

The axles are stock and the stock 8 3/4 right now has 3.23 sure grip. I am going to put in the 4.10 gears to match up better with the new powertrain combo.

When you say "soft" launching? Can you detail what you mean by that?

I dont intend on firing the NOS off the line. If it does hook, I dont think I will make many passes with a stock rear/axles combo with that kind of torque hitting the pavement...

Any opinion on leaving the 3.23 gears in it? Other than the slower ET I dont see a down side since this is mostly a street car that I drive once a week or so...

Thanks,

Doug


PS - Got any specs on your 505?

[Cooter]

The axles are stock and the stock 8 3/4 right now has 3.23 sure grip. I am going to put in the 4.10 gears to match up better with the new powertrain combo.This where most don't understand why they are breaking ring gears/stripping pinion gears. Have you noticed/paid attention to the tooth count on the 4:10 gears pinion? Like 10 teeth? How about the 3:23 gear? WAY more teeth..stronger. 5:13 gear is like 8 tetth or something which is actually weaker for racing. Plus, even the "big pinion" 8 3/4 Carrier (489) will break under hard launching after enough of it.

When you say "soft" launching? Can you detail what you mean by that?RIDE the car out easy on foot brake, then NAIL it once moving.PLUS, all this is in an A-BODY as well. ALOT lighter than a B-body.
I dont intend on firing the NOS off the line. If it does hook, I dont think I will make many passes with a stock rear/axles combo with that kind of torque hitting the pavement...No, you won't.
Any opinion on leaving the 3.23 gears in it? Other than the slower ET I dont see a down side since this is mostly a street car that I drive once a week or so...It will be fine, but "Street" car tends to mean VERY different things to different people. All is fine until late one night, a sh*t talker in a 5.0 Mustang gets your goat and you decide to "teach him a lesson" and you get your ass handed to you...Then, all of a sudden, there's 4:56 gears, roll cage, 400 Shot, and 540 C.I stroker in your "Street car"....

Thanks,
Doug
PS - Got any specs on your 505?Built back in 1996 when 500 inches on the street was just beginning to be done by Hughes engines. A friend bought one of their engines, it blew up (Spun a rod), he calls them to get it "warrantied" they tell him no, he buys a bigger 540 C.I. stroker and I buy his "old" crank with spun bearing. Built with basically what's referred to today as "junk" pistons custom made ($800.00/set back in 1996), and OLD set of Eagle rods I bought used. Has a .562 .562 265/265 Soild lift Comp cam in it, with Single 1050 Dominator on a Team G intake. Has a set of my Ported "915" heads with 2.08 In. and 1.880 Ex. valves. 2" CPPA underchassis headers. Built with junk, and going as fast as junk will take me.Big Dollar RACING engines Masquerading as "Street" engines do NOT impress me. I'm usually the one in the pits with everybody standing around scratching their heads wondering how the hell that POS Dart of mine went that fast.