The subject is a 1951 F1 with 351W and C6 transmission.
I installed a "Heidt" mustang II front axle. The sales people at Heidt felt that I would need 325 LBS springs on each side. However I am going with fiberglass fenders but everything else is original. The truck does not go down when I put 200 LBS on it. My question is does anyone have any opinions regarding the springs. Heidt offers a 300LBS and a 275 LBS spring. I am inclined to exchange them now, but would like to hear from someone that has been through this before.
Thank you

 

How far along are you with assembly? Do you have any sheet metal on it at all, yet? I can see that only putting 200 pounds on the front of your truck wouldn't change the ride height much at all. Theoretically, with 2 325 pound springs, you would need 650 pounds over the springs to compress them one inch. Standing on the front of your frame rails won't do much for you there.

Personally, I wouldn't get too crazy with worry over your spring rate until you've assembled everything, put water in the radiator, and then driven it for 6 months. Coil springs will settle some as they get used. The people at Heidts have a pretty good handle on what works and what doesn't on their suspension systems.

I don't know what the weight difference is between fiberglass and steel F-1 fenders, but I wouldn't think it would be much. The stockers aren't that heavy, and the fiberglass units are not lightweight racing parts, either.

 

Wayne, thank you for your response. You may be right to not get concerned about the stiffness of the springs until it go a few miles and a few months on it. I was not aware of the 650 lbs and the 1 inch comprerssion.
Thanks again.
Roger

 

FYI -- I have 'glass front fenders and I'd be surprised if they weigh 10 lbs less than steel between them. They are the thick "street" 'glass, not the "racing" thin stuff that is floppy.

 

As said, the springs will settle, the process can be expedited by holding the spring partly collapsed (ride height?) with some kind of store bought temporary link that replaces the shock or using all-thread rod in the shock mount to compress the spring while you are working on it.

 

Sounds like a good idea using the threaded stock. What spring capacity are you useing with the 460 ? Just curious.
Thanks
Roger

 

450 I think (it’s a Heidts as well) but that is from a very unreliable memory that could be confirmed if I could remember where I put the invoice! I have had my all-thread in for over 6 months so far and will continue to, because I’m lazy, so I really don’t know what effect it is having, previous projects have settled, and on this one without sheet metal / rad etc I can’t do up the shocks so hopefully it will settle enough to do that.

This is a pic of my ugly-crapy-rotten-stick out to far power steering pump install that kind of shows the coil spring compressed.

 

I don't know what load the all-thread would be under, but the junk they sell at Home Depot is made from melted tuna cans. If you buy there, go up a size from what you think it should be, off-hand I'd say at least 1/2" diameter. Otherwise buy pipe support all-thread at a industrial supply house. It is made of certified materials. I've never done an MII so I don't know if we're talking several hundred pounds of force on the temp rod, or a couple thousand. Any time you're compressing a spring, it makes me nervous -- lots of energy released if the threads fail.