Rear End question

[spyderwagon]

Is a 1975 Vega rear 7.5 like a Monza, or is it smaller or? I realize that Monza is 3 link, and Vega is 4 link. Is the Vega rear also 26 spline?
I also know I can put a Monza 3 link in place of the 4 link. What rear would be better for street/bracket racing?

Thanks
Logan

[NixVegaGT]

I'm super opinionated about this issue so I'll apologize for:
A: Sounding like a know-it-all
B: Sounding close-minded

The 4-link is crap. There I said it. WHEW what a load off. Using a real 4-link to dial in a launch is different. IMO the 3-link is the way to go for street/bracket racing.

SO what do you do if you want a 3-link. Some late Vega's came with it already. Some '75's came with the 6.5" and some with the 7.5". Right?

What are the drawbacks? Well if you want it in a 4-link car you have to fabricate a pad and support for the panard bar. You don't NEED but it is nice to have a 3-link axle with the torque arm mount. Here's a pic of the panard bar perch I added to convert my Vega:



Here's a link to some other options for the 3-link if you want adjustablility:

http://forums.h-body.org/viewtopic.php?t=22482

[v8astregt]

This is gonna be a HUGE matter of opinion.

From what I've seen, it seems like the factory 4-link is plenty capable. I've seen a lot of them run good times in stock form, look at a few members here, specifically rustorbust, he's in the 11's, without traction bars! That's an inspiration for me. I don't know what the fastest time is for a 3-link, but I'm gonna try my best out of the factory 4 link first. All I want is 11's.

[spyderwagon]

Hey guys, thanks for the input.
mid to low 11's is what I am after. I know I got the HP, its getting it to the ground.

Josh, I love your car! I wish I held out for a Astre! That nose and tail lights make that car 100% better looking than my Vega. Also, Josh, I told Chuck to let you have the lift bars. I am holding off until I figure out what I got and what I am doing.

So, I measured my center section. From the inside of the mounting lip of diff cover is 7.5. So I got a 7.5? Or do I need to pull diff cover? Did they stick 6.5 guts in a 7.5 housing? If it is 6.5 I will throw it out the back at track right?

Thanks
Logan

[spyder_xlch]

I'd stick with whatever you have, whether it be 3 or 4 link. Once you start over powering the stock set up then think about modifying it.

[NixVegaGT]

That's a gooc point, Matt. It's worth seeing how it works for you as is.

I was hoping Josh would chime in as a counter point to my argument. He's a good example of someone who's made the 4-link work. I think he will be able to answer my jabs at the stock 4-link setup and in the end we could have a useful thread for those of us deciding use the 4-link or go with the 3-link.

I was never able to alleviate the copious wheel hop endemic to the GM 4-link setup. In fact the wheel hop eventually buckled my lower trailing arm gusset. Having had the luck to have owned both early and later rear suspensions I was quick to decide to swap out for the 3-link.

OK so here's my challenge for Josh. Is it fair to say the stock 4-link might not be capable since you were able to rip off one of your control arm mounts? Maybe your's was an unusual example. What do you think?

[spyder_xlch]

I don't think Josh would have had a problem if he had the stock engine and used it as intended. Once you start putting power to the ground you'll find out real quick what needs beefed up. I favor the 3 link suspension but all my cars came stock with them. If I had an early Vega with a 4 link I'd probably just beef it up rather than change it out for a 3 link. But then again, if I had a donor with a 3 link I might swap it. I'm not much help am I?

[NixVegaGT]

4-link definitely benefits from already being there. No doubt. Retrofitting the 3-link isn't easy. That's a good point.

[v8astregt]

I'm positive that the factory 4-link is perfectly capable. As a matter of fact, I KNEW I was gonna rip one of those mounts off someday... didn't know so soon though. That's what happens when you put solid links in there. But it's plenty strong now, I shouldn't have any issues. I'll just keep an eye on it all the time.

But the stock 4-link has gotten me to a 1.9 60' and 12.595, but I know it's faster at the top end... I'm just limited on top end power, but that's a different topic. Anyways, the 1.9 was with me barely giving it gas off the line, maybe 2k rpm. The launch where I broke was about 3k... as high as I could go before it would creep forward. Too bad, that by far felt like my best launch. Must have if it broke my mount like it did! It is launching though, since my slicks did move slightly on the rims. I don't think launching is going to be the thing holding me back in the end. Once I get drag shocks on, and a higher stall converter, I should be set!

[steelhead]

Logan, The 7.5 has 2 bolts with nuts on the bottom, the 6.5 has 4 bolts 2 down from the top and 2 up from the bottom, this is on the rear end end of the torque arm, so if you got nuts its a 7.5

[cjbiagi]

If he has a 4 link there is no torque arm to check the mounting bolt arrangement.

[spyderwagon]

Thanks to all for the input. It is realy helping.
Josh, 1.9 60ft @ 2k? Is that a street tire? What gear you running?

Lance, I have 4 link. Clyde is correct, no torque arm to look at.

So did GM put 6.5 guts in a 7.5 housing? or is the 6.5 housing smaller yet than the 7.5? I didnt think they got any smaller.

Here is my thing. I am keeping my wagon as my long term progect. Quick slam together this Vega that didnt sell. So I have a 4 link in vega now, unsure if it is 6.5 or 7.5, or I can slap the 3 link from wagon under the vega cause wagon is getting a 8.5 rear.
I have Richmond mini spool 26 spline
5 lug S10 axles
adjustable lowers
lift bars

So I guess I am asking what rear housing/set up to use in little beater vega.?

355, flat top, performer rpm cam, pink rods, B&M mini blower {if it dont sell}, NOS plate system with 75 shot {second gear activated}, th350 with 2200-2400 and shift kit, rear will be spooled with hope 3.73 {still looking for 3.73 non posi center & pinion}, 26/9.5-15 hoosier quick time rear tires.

Thanks again to all
Logan

[res0o7eb]

So, for clarity:

The later H-bodies had 3-link rear suspensions - torque arm, lower control arms plus a panhard bar/rod - had EITHER a 6.5 rear end OR a 7.5 rear-end. Correct?
The early H-Bodies had 4-link rear suspensions - upper and lower control arms - had ONLY a 6.5 rear-end. Correct?

BTW, isn't the 3-link described above really a 4-link, but different that the other 4-link?

As you can tell Matt, I really don't know much about rear suspensions.

[spyderwagon]

So all 4 link H-bodys are 6.5?

Thanks Logan

[v8astregt]

Logan, my 1.9 60' was at 2k, with Mickey Thompson ET Drags not quite heated up as much as they could have. I am running 3.73's, and the posi/28 spline axles I literally pulled out of the boneyard and installed myself with no prior axle experience!!

My previous trips where I ran my best runs I only went up to about 2k because I didn't want to roll through the lights and redlight. I'd practice on the street, but I only spin tires. So this last trip, I went easy on it for a while since I just "had that feeling". Something felt different that night. Then the last run I went balls to the wall. I adjusted the brake bias rearward some, then held the brake as hard as possible, then I think I was up to about 3k when I launched. This was the ticket for sure, I launched HARD! My dad and his buddy said so too... he said I got the front end lifting pretty good. Too bad this is the run that I broke though, lol! I launched hard enough that with the left UCA hanging on by a thread, the rearend shifted about 3 inches to the right during the launch! This I know because my pinion yoke hit the right of the trans tunnel.

I'll tune it some more later, but I'm consistent mid-12s now, I'm very happy with that. I'll build up some money, install bigger headers, single plane intake, and so forth. Besides, it's getting warmer pretty quickly here in AZ.