Joe Lucia

[Bob I.]

Joe -- What are the specifications {free height, lbs/in} for GM front coil spring #45H0174. And of any other springs that are available through GM for a C3

Thanks Bob

[Joe L.]

Re: Joe Lucia

Bob------

Sorry, I don't have the specs for these Delco #45H0174 springs. These are a SERVICE-only spring for all 1968-82 Corvettes with small block and without C-60. These springs, also known as GM #88913487, are not a direct supercession for any coil spring originally used in PRODUCTION for any 1968-82 Corvette.

The other coil spring available for 68-82 Corvettes is Delco #45H0172, aka GM #88913487. This spring is applicable to 68-74 Corvettes with big block and 68-82 Corvettes with small block and C-60.

Once-upon-a-time there were a large number of PRODUCTION coil springs used for 1968-82 Corvettes depending upon model year and installed optional equipment (i.e affecting vehicle weight). Delco has "condensed" these down to only 2 part numbers. So, it's not a one-size-fits-all, it's a two-sizes-fit-all kind of thing. Actually, I believe that these springs are aftermarket springs packaged in Delco boxes with Delco/GM part numbers. Their source is very likely Moog/Federal Mogul.

I'm not casting aspersions on the functionality of the springs, though; they may work very well.

[Joe L.]

Correction

The Delco #45H0172 spring is also known as GM #88913485 and NOT 88913487.

[Rick M.]

Re: C3 springs

Joe and Bob,
Very interested in your comments on front springs. Am doing a chassis resto on my 69 big block. It's riding about 1 to 2" low. Would like to have flight judged at some point. Joe's comments about springs not working well has me concerned. Finding correct springs is hard and if they don't work, maybe I should just clean up the originals and move on down the road.
Your thoughts?
Thanks,
Rick

[Joe L.]

Re: C3 springs

Rick------

I didn't mean to imply that the Delco-available springs wouldn't work correctly. They may work very well and provide a correct or near-correct ride height. I just don't know, for sure, since I've had no experience with them.

Actually, I would THINK that the big block version of the Delco spring might very well work out ok.

What is the free length and general condition of the original springs when you removed them from the car? That's important to assess how close to original specs they are. If they're still in good shape and close to original free-length specs, I'd say they should be good to re-use.

[Terry F.]

Re: C3 springs

It has always been my impression that it takes very little change in spring length to cause a height adjustment. I have been tempted to slip in a small stainless shim or similar (maybe 1/8 to 1/4 inch thick) between the end of the spring and the lower A-frame. Paint it black and it would be hard to see. From an esthetics point of view, I feel that corvettes look much better when they are level with the ground. I don't like a nose down appearance. Best regards, Terry

[Rick M.]

Re: C3 springs

Thanks Joe,
Haven't removed front spring yet. We started at the back of the car and have the frame done up to the front wheel wells. Now it's time to tear down front suspension. Will measure front springs to check specs but the car rides too low now. Have a oil pant scuff etc. Terry had a great point and I agree, what ever I do the car MUST ride level. They don't look right if the back ends to high.
Anyone have any ideas on a correct rear spring, corners turned up etc.?

[Bob I.]

Re: C3 springs

Rick, What I found out about the GM springs. Is their a replacement style meaning different free height and pressure similar to a catalog spring. I installed a TRW spring with a free height of 13.13" and pressure of 474 lbs. I have a small block car it now sits an inch higher than the AIM height. Hope that helps, I belive Eaton makes a repo spring.

[Terry F.]

Re: C3 springs

A long time ago, I purchased over the counter springs for my 68 at GM. I tried to install them and the front end wouldn't even come off the bumpers they were so stiff. Was sort of funny. I rebuilt my front end and installed the original springs and the ride height is fine now, maybe a little high. I expect it to settle with use. My original springs had remnants of the original lables and had only light surface rust. Good luck, Terry

[Rick M.]

Re: C3 springs

Heard about the Eaton Spring, they claim it's identicle to the original. If I can do the same on the front I'm good to go.

[Rick M.]

Re: C3 springs

Interesting, I have the label rements as well. Am missing one of the upper bumpers. Was the front end higher after the rebuild, even with original springs?
Thanks,
Rick

[Terry F.]

Re: C3 springs

Yes, front end sat above normal height after rebuild. They are standard springs in a 68 bb. I know a place that makes large springs. I should ask them if they can stretch a spring?? That might work for some people. Terry

[Mark #28455]

F41 springs

For a replacement F41 spring, get the heavy duty MOOG spring for the 1968 Impala - has the same wire size but 16" tall instead of 12+. Costs about $90 at Summitracing.com then cut off the extra height with a cutoff wheel. If you run the calculation, you get the correct wire diameter, free height, and spring rate.

Mark

[Rick M.]

Re: F41 springs

Thanks Mark but mine aren't F41. What you recommend for standard.
Thanks,
Rick

[Mark #28455]

Re: F41 springs

My cars all had F41 suspension so I haven't been up against this before. If I remember correctly, the standard BB springs were progressive rate springs (at least the AC cars were) so just cutting down another spring is unlikely to provide a satisfactory replacement. If the repros sit too low (that seems to be the most common complaint) you may be able to raise it by 1/2" to an inch with a rubber "coil spring insulator" - commonly available in 1/4" to 1/2" thickness. It is placed in the spring pocket before the spring is installed. Pretty hard to see while the car is on the ground, but certainly not factory correct.

Sorry
Mark