driveline loop ?'s

[low&slow]

I'm sure this has been covered once before, but never hurts to bring up the topic again.

If I was to run a 1 piece driveline in a long bed, would the original drive shaft cross member be considered as a proper driveline loop?

OR

If I was to run a 2 piece driveline, would I have to add a driveline loop?

[71Dragtruck]

No it won't work, NHRA loop has to be min 6" from the end at the front. there is also specs such as 2" wide and 1/4" thick with 360* enclosure, can't remember the specs on made of tbg. off hand and my rule book is at home.

[low&slow]

6 inches from the end of the driveline?

[71Dragtruck]

From the front yoke back 6"

Just trying to find the link I had for online rulebook so you have the proper wording.

[71Dragtruck]

http://www.nhraracer.com/content/gen...000&zoneid=132


DRIVESHAFT LOOP DEFINITION: 360 degrees of enclosure,
1/4-inch minimum thickness and 2 inches wide, or 7/8-inch x
.065-inch welded steel tubing, securely mounted to the frame or
frame structure where available (or to the OEM floor or rocker box
where a frame does not exist) and located within 6 inches of the
front or rear universal joint for support of the driveshaft in event of
U-joint failure.

[low&slow]

That makes sense. Is there suppose to be one for the back as well or just the front?

[71Dragtruck]

Originally Posted by low&slow

That makes sense. Is there suppose to be one for the back as well or just the front?

Just the front as far as I know, it's kinda worded weird the way they have it, but I've only seen them on the front.


Mine runs through my 4 link x-member also so kinda has one at the back also.

[KQQL IT]

Loop in the 73

[Marv D]

71 absolutely not trying to dispute you,, just clarify NHRA General Reg 2:4 says...

For all full-bodied and open-bodied cars running between 7.50
(*4.50) and 13.99 (*8.59) in place of a crossmember located
behind but within 6 inches of the center of the front universal
joint: A front driveshaft loop is required on all cars, except
vehicles running 11.49 (*7.35) seconds or slower equipped with
street tires. See Class Requirements.

The grey area there is DOT approves drag radials and DOT slicks like the ET streets / QTpro's

That said, the trailing arm cross member in the 62-66 SWB is just @ 9" behind the cross member (with a TH400) Because it's such a massive piece of the frame, and fully captures the drive shaft.... they have not given me any troubles at all not having a driveshaft loop running high 10's.

Now, that doesn't mean it meets the rule,, it just meets the rules 'intent' and all tech inspectors "I have ran across" will let it slide. That's not saying your inspector will have the same attitude,,

I believe IHRA rules are a lot more lenient ,, if I recall correctly IHRA is 10.99,, but don't quote me on that

but I'm just saying.. it depends LOL

[71Dragtruck]

Yeah if that's the case like Marv said and you have a turbo 400 setup like that, I doubt they would say anything about it being 9" away. I was just thinking on my truck where the crossmember held my steady bearing on a two piece.

[Marv D]

Again,, mines a SHORTBED,,, I don't know if that moved the trailing arm forward compared to the long bed,,


and,, I just realized also my SBC is stuffed as far back against the firewall as it will go (front plate / mid plate not factory side motor mounts)

So really only thing realitive I posted is... if your not running 11.49 or quicker,, and if your running DOT tires.... you don't have to have one. But if you are putting one in anyways.. DO I RIGHT (DUH!)

I always thought if tech gave me issues, I'd weld on loop of 2.5" strap to the face of cross member and let them argue with me about that 1/2" . You can just see that massive crossmember in this link ... it's not letting anything get away!

LOL again unless your running a NHRA national event I really doubt they are going to get under there and see if you even have one,, and if they do they arent going to measure for the 6"

The intent of 'is it captured' is more important than the measure of a couple of inches.

[regan wilson]

I cut out the old style strap loop and Brad built this double loop with tubing.