LFZ

got a HD 7 leaf spring..whats the rating on it? 300lb? maybe...?? :cheers:

nuolitie

I have same guess that you, maybe 300lbs, but im not sure...

And if it is 300 it is hard to me to understand why all stores sell performance packages where they combine 550lbs front springs with 360 composite one (not like GM originally offered F41/HD/Gymkhana 550front 300rear) :cuss

Frankenvette

I've seen two different ratings in the vette catalogs...290lbs and 330lbs.

hunt4cleanair

Quote:

got a HD 7 leaf spring..whats the rating on it? 300lb? maybe...?? :cheers:

Ratings for 7 leaf springs were 550 lb/inch. That would be for an F41, FE7 or Z07 HD setup.

nuolitie

550lbs??? Do you mean FRONT? I think the question was REAR? :troll

JohnS_77

I called Zip yesterday looking for this info. They said they would call me back today. :lurk:

LFZ

cool..let us know! :cheers:

Rowdy Rat

Herb,

If it is a GM heavy duty (seven leaf) rear spring, the spring rate is 152 lbs/in per side... Or about 305 lbs/in total. The following list of spring rates is correct for the 1968-1972 model years (there may be carry over into later years, but I am unsure of particular applications):

FRONT SPRINGS

327/350 (no A/C) - Part #3931823 - "HS" - 250 lbs/in
327/350 (with A/C) - Part #3931824 - "HT" - 264 lbs/in
427/454 (no A/C) - Part #3931825 - "HU" - 284 lbs/in
427/454 (with A/C) - Part #3931826 - "HV" - 325 lbs/in
F41 (all) - Part #3832518 - "EA" - 550 lbs/in

REAR SPRINGS

327/350/427/454 (except F41) - Part #3850839 - "EA" - 70 lbs/in (per side)
F41 (all) - Part #3828811 - "EB" - 152 lbs/in (per side)

The springs were actually chosen based on sprung curb weight, but it usually took the addition of air conditioning to require a change to the higher rate spring (which is why I listed it as "with a/c").

If it is a non GM spring... Who knows what the rate may be? There is equipment to test the spring, but is it really worth it? Probably less expensive to go out an buy a new spring with a known rate than to go to all the trouble and expense of having this one tested.

Regards,

hunt4cleanair

Quote:

550lbs??? Do you mean FRONT? I think the question was REAR? :troll

Ah....yeah! A 78-79 rear spring was rated at 305 lb/in with the number of leaves set at 6. From 74-77, FE7 carried 7 leafs and rated at 305 lb/in. In 80-82, the 9 leaf FE7 was rated at 294 (estimated). Remember less weight than earlier vettes through weight savings.

So your REAR spring part number is 462598.

JohnS_77

They never called. :nonod:

LFZ

Rowdy Rat...thanks, I was hoping it was around 300lbs. It is a GM 7 leafer. I hope it will accomodate my 460 minus one coil front springs. :thumbs:

nuolitie

Thanks RowdyRat!!!!!! Good details that I have hounting after for a long period already :party: