Drag tire question

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65 Mopar

65 Mopar

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I bought a pair of slicks and am nervous about breaking an axle or something once the thing hooks up.. It may sound like a silly question but I don't want to break an axle and damage the car. I don't even know what kind of power it would take to break it!

What I have is a 8-3/4 with 355 gears
Running a 340 (probably 360 horse) through a built 904 with a 2800 stall...
 
Only one way to find out. :steering: I can tell you there are a lot of guys on this site that are putting more power through an 8 3/4 than you are and they seem to hold up pretty well.
 
I run 10.60s on a factory suregrip and a 5000 Flash converter on ET Drags. I think you're good ;)
 
65 Mopar said:
Thanks guys!! Sorry I'm so green!
Click to expand...
An old friend ran a 8-3/4 with slicks behind a 440 RB in the mid to low 10's for years.

Once you start in with some power, look to frame connectors and a cage.
 
is a good question,if parts are in good working order you will be fine but upgraded mounts are a must.the large sidewalls on that style of tire will help some.
 
I know from a particular 73 duster (uncle's car) that factory 8 3/4 axles are pretty bulletproof with 3.73s and around 450hp on a 3k stall. Doubt you'll be in any trouble, but IMO if you break you break, it happens
 
Make sure that your driveshaft and u-joints are in VERY good shape. That might be your weakest link. Wheel studs might be next. I prefer Spicer solid u-joints. A driveshaft loop couldn't hurt either. But frame connectors will help minimize flex and body cracks even with OEM engines that are driven hard.
 
This is all great info! I feel much better..
I just put fresh u joints in and the shaft is sound (far as I can tell).

I'm not planning on running it at the drags but maybe twice this year and a couple next.. I just want the 12's bad! I ran a 13.03 on my street tires and am hoping to make it to the 12's without breaking anything. So much fun..but it can be so much cost..
 
The likelyhood of breaking an axle is pretty slim; drive shaft and u-joints should be of more concern and the area of regular inspection. Watch for stretch of the bearing cup eyelets.

You didn't say what size slick it is you are running?

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also I think you need to have a driveshaft loop and 3" wheel studs with slicks. not 100%
 
*I think* that goes with a certain ET.
 
65 Mopar said:
This is all great info! I feel much better..
I just put fresh u joints in and the shaft is sound (far as I can tell).
Click to expand...

"IF" your new u-joints have grease fittings, are they in the cap or in between the caps? If they are in between the caps (in the u-joint body), they should be "in compression" - (Slip yoke ears should be turning towards the fitting and rear driveshaft yoke ears should too.)

Hope that makes sense. Torque should be compressing the joint where the grease fitting is instead of trying to spread it where it's the weakest, at the grease fitting hole.
 
First time I ran slicks I dropped the clutch , snapped an axle and motor mount ! Engine rotated and put a huge dent in the hood !
 
Locomotion said:
"IF" your new u-joints have grease fittings, are they in the cap or in between the caps? If they are in between the caps (in the u-joint body), they should be "in compression" - (Slip yoke ears should be turning towards the fitting and rear driveshaft yoke ears should too.)

Hope that makes sense. Torque should be compressing the joint where the grease fitting is instead of trying to spread it where it's the weakest, at the grease fitting hole.
Click to expand...

My grease fittings are in the cap. I was told those were the stronger of the two? Are the cap ones better then the ones with the grease fittings in the middle of the u-joint?
 
65 Mopar said:
My grease fittings are in the cap. I was told those were the stronger of the two? Are the cap ones better then the ones with the grease fittings in the middle of the u-joint?
Click to expand...

Yes, they are stronger because the grease fitting hole in the main body actually compromises its strength and is a potential starting point for a crack. It's OK for every day use. IMO the best u-joints are solid, pre-greased by Spicer.
 
I can't say for sure. But I did get some that were 7260-1330 or 1310. 7260-7290 seems like it would be more popular.
 
In oils use a few. Solid or not. Who makes them?
 
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