Great tech article by the guys at RodAuthority today.

http://www.rodauthority.com/news/choosing-the-right-springs-and-shocks-for-your-hot-rod/

Ridetech is a company that is a pioneer in providing performance handling for the popular cars out there and they have a lot of great products. This link is a great starting point for owners to see what they may need for spring rates instead of just guessing or taking the word of the forum community. I'd say this is more of a spring rate selector than a suspension selector, but that's nit picking.

There are a couple of gotchas for mopar owners who work through this formula. One is a big block mopar, especially 2nd gen Hemi powered cars, are up around 57-58% front weight bias. While only a couple percentage points off from the generalization of 55% provided by Ridetech, that can be a significant difference. Certainly if you take the time to scale your car, you will get this data most accurately, but somehow I think a bunch of guys will just plug in guesses. Second, since mopars don't use coils, the angle of coil mounting variable on their calculator can't be zeroed out. Best solution in this case is leave it at 90*. Fortuantly the motion ratio can be seet at 1:1 to duplicate the t-bar motion ratio.

Plugging my own data into it, it seemed to be pretty close to what my own calculations say. However, everyone should be aware that this calculator is ONLY spring rates and does not include sway bar loads and their related motion ratios and their impact on the wheel loads. But, that does create a more complex and cumbersome set of formulas. However, getting spring rates more dialed in means you can then use the sway bars as a tuning tool instead of a crutch.

It was a bummer to go through the classic car weight data base only only find a '65 New Yorker and '69 Super Bee as the only mopar choices. The rod girls page was fun.

Do they sell suspension parts for Mopars (torsion bar springs, etc.?) Their product and selection tools look nice but all I see is GM or coil over Hot Rod stuff on their site? How does any of that relate to a Mopar?

They on't offer t-bars or leaf springs and as a distributor for companies like Flaming river, Wilwood, Ridetech, etc, they may have some parts that can be used, but I do not see a mopar specific section. Of course, a lot of street rod guys do use aspen/volare front subs under their rides, which is what motivated Fatman to create the first mopar drop spindles over a decade ago.

The biggest benefit of that link is it drops you in to an article that explains how to choose your spring rates. Provided you take a couple of precautions that I explained above. To a lot of guys, spring rate selection seems like voodoo. And mopar dudes in particular seem to always err on the side of too soft in their selections.