Redoing a complete front end on my 71 big block with AC, including the steering (looking at converting to a Borgeson upgrade while i'm at it).

Have many of the parts already or on order (KYB's, Moog mostly), with exception of coil springs.

My front has 126K, original with even the riveted ball joints. The coils are shot (looked under and they even have coil spacers shoved in to keep the sagging up- dangerous).

I'm pretty sure I want to go with Moog 5762. Though some info is different out there, it is listed as having 474 lb rate and it is for AC cars (does that mean BB and AC, not so sure):

Even if this spring is indeed only for small block cars, I think it would be fine in a street driven big block 454. 

I really don't want some of those 550 lb. springs they say to use; However, maybe 550s with a Big Block may not be too harsh.

My thinking is the factory springs were way too soft anyway, and the 474lb would be an improvement. 

I've spent hours researching this, reading numerous forums and listening to manufacturers' claims to buy their brand.

Any recommendations and/or advice? 

So many vendors list the same vague info. For example:

Even Willcox has confusing information on BB coils w/ AC (check out this link):

Listed as Small block and Big Block with AC coil, it actually has the Moog part # in it (5762-36832)! I find it hard to believe that Moog 5762 just happens to be Wilcox's part # too.

I ended up buying from VB&P; the Grand Touring Plus Kit; which comes with a 460lbs coil.

Before making the purchase; I called them to validate my concern about weight.  Since I don`t drag or race... he said I would be just fine with this kit.  A lot of people fine the higher rated kits a little hard.

Something else that could make a difference is your tires.  I chose to stay on 15" instead of 16 or 17; so it cushion`s the ride.

I wish I could tell you how it ended up; but I`m starting the installation next month...  However, from my phone conversation with them; I really feel I made the right choice by not going with a "big block kit".  I felt the specs were a little too stiff for me and for how I like to ride.

Edit:

I was also concerned about the ride height.  The vendor said that since I`m still on the original coil; they are already a little lower because of age.  Just the fact of going with new coil; should bring it up a tad and the end result should "feel" normal.

Steph.

I'm sure they'll be able to answer your concerns.

Bair's

You try to be as thorough as possible, do your own homework/research to make sure you're well informed (and the part is correct)... and there's still questions. With car resto's, that seems to always be the case.

I'm not going the "correct" route, even though I could get an "exact" spring. Yes, today's springs are made shorter so they are somewhat easier to install. A shorter spring with larger diameter coils will provide a more flat ride, a good move in the handling dept.  

Manufacturers seem to miss the mark on these simple areas- Corvette coil springs. Obviously I see why- you only need two for the front. Still, I come from a retail business side, and all vendors really ought to market these things more appropriately. In other words, truly sell what they really are selling. Being vague just makes most people skip the purchase- that goes with any part.

I feel my springs are shot, even with coil spring helpers in the front. 550lb springs with a big block isn't a bad idea, but I'd rather not be so stiff. 

And this coming from a guy who's '69 Malibu had a full Hotchkis suspension, including 2" drop progressive rate coils and KYB's. Very stiff ride with a small block. 

284 lb, 1540 Load, part# 3931825, code HU

325 lb, 1620 Load, part# 3931826, code HY

There's also:

550 lb, 1290 Load, part #3832518, code EA

It's seems odd that a small block would have the same 550's as the BB in F41- they would ride extra stiff.

Given a stock 454 (mine is an '71 LS5 365hp) only had a 284 or 325 spring- how would 460/474 (depending who you purchase, Grand Tour vs. Moog, respectively) be not enough?

Shorter, stiffer than those old springs, they would not compress so easily (obviously).