Hello forum: I'm hoping someone can shed some light on my problem. I'm doing a LS3 conversion on a 1969 C3. Since the LS3 motor is 275#'s lighter than the small block 350. The front springs will not compress as far enough leaving the front sitting to high. I have 460# springs and have not been able to find any with a less poundage. An suggestions? I'm not big on cutting coils off ( but will if need be). And new tube control arms and coil overs not in the budget yet. Anyone out there come across this problem. hanks Kurt

 

Im pretty sure 550 lb springs are suppose to be like an inch shorter than stock, also I believe Vbp makes a conversion to a front monoleaf that would make it adjustable, cutting coils would be alot cheaper though

 

I have the 550 front springs 1 inch shorter than stock and I do not think that they will solve your issue. My ride height was perfect with these springs until last Spring when I rebuilt my L-82 with AFR aluminum heads and I have to now cut probably about 1/2 coil to get the front height down. With a an LS3 engine that is 275lbs< than my Gen 1 SBC, I don't think these springs will work. My L-82 has besides the AFR aluminum heads also aluminum water pump, aluminum radiator, MUCH lighter shorty headers, aluminum L-82 intake, and no AC compressor so I doubt the difference in weight is anywhere near 275 lbs BUT it is still significant...

 

On one end of a coil spring, the coils are wound "tighter". Cut 1/2 a coil (wrap) off the tightly wound end.....you will lower the car without affecting the ride quality. Then drive the car to get the suspension to "settle dowm". This can be repeated until the car is lowered to your liking.

I found this formula just now for cutting a coil spring so the spring sits in the upper and lower pockets correctly:

 

Try these. They're probably the lightest you'll find but you still may need to cut them.

http://www.parts123.com/corvettecent...50g&ukey=11479

 

Since the block's CG is aft of the front axle rather than sitting directly above it, the effective weight reduction on the front springs will be ~230#, the remainder coming off of the rear. The effective leverage had by the front coils at the front tire CLs (wheel rate) is only about 1/2 that of the springs themselves. So, with 460# coils, this 230# weight reduction would raise the front ride height by ~1/2".

But, bear in mind that we're looking at more than a simple ride height issue here. Since the car's CG will be moved towards the rear, its front/rear weight distribution will also be shifted that direction by somewhere in the neighborhood of 3% as well, which will necessarily increase the car's tendency for understeer from wherever is its current state of balance.

And, then there's the little matter of having reduced the sprung to unsprung weight ratio. Long story short, this will serve to increase effective spring frequencies (at the front much more so than at the rear), which means a less compliant ride even with the same springs. What to do about this (if anything) depends greatly on the roads on which the car will most often be driven, as well as your purposes.

In any event, I'd highly suggest leaving the suspension be until you have the chance to diagnose where you are relative to where you want to be (ride heights, handling, comfort...) until after the weight reduction. YMMV


TSW