Tech Question - Streetrod w/ Corvair Suspension II

Q -Mike

A little help please. I have a 35 Master Chevy Sedan with 305 V8 350auto/no a/c (yet). Front suspension consists of Mustang rack and Corvair suspension with S10 rotors and calipers.

I need springs for the front end and have heard Mustang II springs "might" work. I would like to make this a daily driver, however it sits way to low to be practical in my area. it looks good this low, but practicality takes a back seat. I'm sure I can get it still reasonably low with new springs, but am at a loss for what spring to try first.

I know better than to rely on information from someone who says "might work", and decided just go straight to someplace/someone who would actually be knowledgeable. like somebody who works at a spring company ...thanks for your time Mike and I look forward to your reply. - Dwayne

Dwayne,

My 1st advice is to get rid of the Corvair suspension. Over time it will prove to be a difficult thing to maintain because of part availability.

That being said, let's look at the differences between the Corvair and Mustang II coil springs. Coil springs are sized by the ID (inside diameter) of the spring. The ID remains constant no matter what the wire size is.

Now that you know that, Corvair springs have an ID of 3.49 Inches. Mustang 2 springs have a 3.5 Inch ID. So by ID the M2 spring will fit.

The ends of the Corvair springs are both tangential, that is they twist off into space and the spring would fall over if you tried to stand it on it's end. The ends of the M2 springs are one tangential and the other square. The square end allows the spring to stand up by itself.

A square end can be turned into a tangential end by cutting the square end off.

The Corvair springs, and there were 2 used, have free lengths of 12.7 and 12.02 Inches.

The Corvair springs have spring rates of 162 and 188 Lbs. respectfully. Rate is the amount of weight required to deflect a spring one Inch.

The Corvair springs are designed to be 7.5 Inches tall at 854 Lbs., that is the spring will compress about 5 Inches when 854 Lbs. of weight is put on it.

The lightest M2 spring has a rate of 308 Lbs. and is 14 1/8 Inches tall. This spring would be 9 Inches tall with 1,555 Lbs., or 11 3/8 Inches tall at 854 Lbs.

The shortest M2 spring is 13 5/8 Inches tall and has a rate of 315 Lbs. It would be 9 Inches tall at 1,468 Lbs., or 10 7/8 Inches tall at 854 Lbs.

While a square end M2 spring can be converted to a tangential ended spring by cutting the square end off, cutting the spring shorter will increase the spring rate. The amount of rate increase depends on the amount of the spring cut off. Learn all the math here.

Now with all this being said, can a M2 spring be used in place of a Corvair spring? Yes, the M2 spring must be cut and the ride will be firmer. Now which one of the 23 M2 springs should be used...I don't know. That is something you would have to experiment with.

Now bear in mind, once you cut the spring it is yours. we will not take it back.

The complete list of Mustang 2 springs we offer can be found here.

Mike