Speedway motors/ Hiedt IFS

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MoparCrazy78

MoparCrazy78

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Hello all, I have been digging through all the threads about aftermarket ifs kits and have yet to see anyone using the Speedway Motors Mustang II kit. It is half the price of a few others, so is there a reason other than not being a bolt-on? I'm seriously thinking about moving to something more modern and weighing options. The kit I saw was hub to hub for 1379.00 plus tax, crossmember, and shipping.
 
A link might help you get some opinions.
 
I haven't seen a Speedway catalog since 04'. Must be a newer item! I haven't heard anyone on here talk about them, so it might be fairly new. Speedway does mostly circle track stuff, so unless they race, they probably don't get the catalog.
 
The problem I see right off the bat is that they don't offer one specifically for an A body. You would have to use one of the multi-fit kits, meaning lots of fabrication. Take for instance the Alter-K-Tion kit. It is a complete K frame that bolts in, and is specifically engineered for the A body. It also has the motor mounts in the right places. I think this kit from Speedway would be good for someone that is real good at fabrication.
 
It does look like a good bit of measuring and fab, but the price is sooooooooo nice comparatively. Bolt on vs fab and more fab, hmmmmmmm
 
If either the 56" or 60" track will fit your build go for it. Make sure you know if that is a hub to hub track, rotor flange to rotor flange track, or normal track measurement which goes from the center of each tire My guess is hub to hub but I didn't look close enough. Shouldn't be too bad a job really. If you want something made for the a-body, but less costly than an RMS, Martz chassis has something that is a weld-in replacement with coil-overs, 2" drop spindle etc. Pricing is higher than Heidts but that's the Mopar world.
 
I'm still in the research phase right now, but it is still sounding sweet. I'll be around a while, so it will likely be a build thread when it's time.
 
personal opinion the speedway motors products are junk, ive had some UCAs for my gbody, and they are low quailty and even had "cold welds" compared to the hotchkis they are for show only.
 
I don't understand at all the obsession with replacing the torsion bar suspension. The mustang II set up isn't really inherently better for handling, especially when it gets grafted on to a car that wasn't designed for it. I mean, I understand swapping out a straight axle and leaf springs for a MII set up for a hot rod, straight axles aren't for everybody. But there's no reason that the torsion bar suspension on our cars can't outhandle a MII set up if the right components are used.

By the time you're done with the MII conversion, you could have just bought a Hotchkis TVS kit, bolted it on, and be pulling a lateral G on the skid pad. All suspension systems have pro's and con's, the MII isn't different in that regard.

And if you're really set on replacing the torsion bars, the Alterkation set up is the way to go. The hard work has already been done- its not just about making it fit, its about making it all work properly. And if you want better handling, that will be key.
 
MoparCrazy78 said:
Hello all, I have been digging through all the threads about aftermarket ifs kits and have yet to see anyone using the Speedway Motors Mustang II kit. It is half the price of a few others, so is there a reason other than not being a bolt-on? I'm seriously thinking about moving to something more modern and weighing options. The kit I saw was hub to hub for 1379.00 plus tax, crossmember, and shipping.
Click to expand...

Here we go again.
Compare the A body Mopar front suspension geometry to any Mustang II based suspension. Are all the basic suspension parameters similar or the same? Where are the roll centers? What do the camber curves look like? Pretty similar so far, isn't it?
Is some or most of the springing medium sprung or unsprung weight? Where are the front suspension loads taken into the chassis? How much do you need to stiffen up the engine box to properly transmit the front corner loads into the rest of the chassis?
The same basic A body Mopar suspension was used on the production line from the very early 60s (60-61s were slightly different) through 76 and in modified form (F,M,J,) until the late 80s. The Mustang II suspension was used from 74 to 78.
Are both good production based SLAs? Absolutely.
Is the Mustang II based front suspension more modern? Because it copied the basic parameters of a Mopar suspension in production twelve years ahead of it and contemporary to it, some might say so.
Is it more sophisticated than a Mopar suspension that takes front end loads at the center of the chassis instead of directly at each front corner? Not even close.
Will it make your car handle as well or better as cars costing five times as much (can we say Green Brick)? Good luck with that.
With all the modern little tweeks available for the torsion bar A body suspension that will kick it up to the level of the most capable of the current production sedans, is it worth spending two thousand plus dollars to get rid of those pesky torsion bars, because that's really all you're doing?
Only you can make that decision.
 
The only reason I would consider this system would be for header clearance.

Too much work, no reward vs. upgrading to to 73+ disc/bolt-pattern and adding any of the myriad of factory-compatible aftermarket parts.

I'm not sure what you mean by "something more modern", this suspension design is almost 40 years old...

Are you willing to graft in frame-rails for the MII Kit? That's fun... Even installing one for my friends 65 Stang, which the kit was specific for 64-66's, wasn't that easy. Putting one in an A-Body would be... um... interesting hahaha
 
The biggest two reason's I want to change the front end are the torsion bars and the big steering boxwith the linkage being behind the crossmember.. I don't know if it is worth that amount of money to me just yet, but having fewer parts to develop play in my steering setup is appealing.Plus, I'd really like to be able to use mid length headers like a clipster. I started this thread to get just what I got and maybe a little more as far as info goes. How long should I expect oem idler, pitman, and tie rods to last under medium driving habits? I don't autocross or anything but I don't make a habit of slowing down more that necessary for upcoming curves in the road. My previous a bodies didn't corner well at all, but they were non sway bar '73 front suspension with factory sway bars. I've seen the page for the green brick but haven't really looked into the car's set up.
 
Torsion bars are just springs. The only difference between a torsion bar and a coil spring is the shape. Honestly, I think the ability to easily adjust the ride height of the car without altering the spring rate trumps any cons the design might have.

As far as headers go, there are quite a few really nice options available now. For a mid-length header, you might want to check out Hedman "tight-tube" headers, there's a whole thread on them here. They seem to fit about as well as any of the headers for a-bodies, they're some little issues but nothing that can't be overcome. There's a few people on that thread currently running them on power and manual steering cars.

here's a picture...
attachment.php


As far as the "big" steering box, only the power set up is "big". The manual steering box is pretty small, and is actually used in quite a few hot rod applications BECAUSE of its small size. As far as being behind the K frame, the only real disadvantage of this is being in the way of the headers. But, there's plenty of options for headers now that address this.

As far as handling, there are TONS of threads on here about making your A-body handle better, from mild upgrades all the way to autocross and road racing prep. Here's a quick list I just posted a couple days ago. And as I mentioned before, for the price of converting just the front end you could buy the Hotchkis TVS kit ($2k from Summit) and have upgraded ALL the suspension on the car to a level that performs very well on the race track.


72bluNblu said:
autoxcuda would be the guy that you really want to talk to on this one. He's actually out there racing!

As far as setting up your car goes, there are some simple steps to take that will really help things out.

In the front:

1" torsion bars or larger
Reinforced LCA's
Offset bushing for the UCA's (to get the alignment right)
All new bushings, ball joints, tie rod ends, etc.
Front sway bar (preferably aftermarket, ie, larger than stock)
Good shocks!

In the back:

120-140 lb/in springs, roughly zero arch
All new bushings
Good shocks
Rear sway bar

For the car:

Lower is better
Subframe connectors
Rebuilt or upgraded steering box (Firm Feel, faster ratio's, etc)
Brakes- if you've got 9" drums all around, that won't cut it. 10" drums and the standard 10.8" disks are fine to start. Bigger puts you in a different class most times anyway
Wheels - 15-17" rims, modern compound tires (NOT T/A's)
Alignment- 0 to -.5 camber (or more for racing), +3 to +4 caster, 1/16" to 1/8" toe in
Click to expand...
 
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