67 Big Block Front Springs

[Thomas N.]

Hi:
Does anyone know what the wire diameter and free length of 67 Big Block front springs are, in standard suspension configuration, and the F41 configuration? Thanks!

[Joe L.]

Re: 67 Big Block Front Springs

Hi:
Does anyone know what the wire diameter and free length of 67 Big Block front springs are, in standard suspension configuration, and the F41 configuration? Thanks!

Thomas------

standard big block (GM #3888250)------17.35" free length; 0.60" wire diameter

F-41------------(GM #3832518)-----------12" free length; 0.70 wire diameter

By the way, the above may differ from specs listed elsewhere. However, these specs were determined empirically from NOS original springs.

[Wayne M.]

Re: 67 Big Block Front Springs

Here's an NOS (service) 3888250 I have, in GM box, dealer ship tags dated 1978.

12 complete coil turns. My Rev 7-1-69 P&A30 shows this last being used on '67 427 L36/L68 and L71 (except C60, and except F41).

I know Duke, John H. and Michael H. have posted extensively on the specs of all the C2 springs, in the past. I wrote down the info somewhere, but can't locate it now.

I know the F40/41 has 9 complete turns. My '69 catalog shows it (3832518) for '63-69 w/Sp. perf. Susp., H.D. Susp.

Other than that, the catalog shows all spring #s for '68-9 change.

[Thomas N.]

Re: 67 Big Block Front Springs

Thanks for the information. I tried the archive search but came up empty. I guess the search engine is smarter than me.

[Joe L.]

Re: 67 Big Block Front Springs

Here's an NOS (service) 3888250 I have, in GM box, dealer ship tags dated 1978.

12 complete coil turns. My Rev 7-1-69 P&A30 shows this last being used on '67 427 L36/L68 and L71 (except C60, and except F41).

I know Duke, John H. and Michael H. have posted extensively on the specs of all the C2 springs, in the past. I wrote down the info somewhere, but can't locate it now.

I know the F40/41 has 9 complete turns. My '69 catalog shows it (3832518) for '63-69 w/Sp. perf. Susp., H.D. Susp.

Other than that, the catalog shows all spring #s for '68-9 change.

Wayne------


Does your spring measure 17.35" from coil end to coil end? This might not be the GM protocol for spring free length measurement, but that's how I measure them.

[Bill M.]

Re: 67 Big Block Front Springs

Wayne------Does your spring measure 17.35" from coil end to coil end? This might not be the GM protocol for spring free length measurement, but that's how I measure them.

Joe: FYI, The Chevrolet Engineering drawing has free length of 17.35 for the 3888250. My NOS 3888250 measure 17-1/4. Bill

[Wayne M.]

Re: 67 Big Block Front Springs

Joe, Bill --- my NOS 3888250 measures 17_7/16" (17.44"). first I shimmed the spring so that it rested vertically on my bench (would'a been a mini tower of Pisa otherwise). Then I measured from bench surface to top surface of end coil. The OD of the wire calipers between 0.596 to 0.602", at several locations.

[Richard F.]

Re: 67 Big Block Front Springs

That difference in height is what makes F41's so much easier (and safer) to R & R. No preload to speak of.

[Timothy B.]

Re: 67 Big Block Front Springs

I have a nice set of 1968 BB springs, does anyone know the wire dia. and height for these.

[Dale C.]

Re: 67 Big Block Front Springs

Tim
This should help. This is for a 68 car.
Dale

[Bill M.]

Re: 67 Big Block Front Springs

TimThis should help. This is for a 68 car.Dale

I think there is something wrong with the free heights.
Take the 3931823 for example:We have design height of 10.0, design load of 1395 and spring rate of 250.
Free height should be 10.0 + 1395/250 = 15.57, not 12.08

[Dale C.]

Re: 67 Big Block Front Springs

Bill, you are correct I just measured my 3931826 HV for 68 BB with A/C and they are about 15.5 free height and Tim the wire dia. is .645.
Dale

[Thomas N.]

Re: 67 Big Block Front Springs

The reason for my inquiry is, I bought a pair of used 250 springs and still am unsure if these are proper or not. The free length is 17.31" for one and 17.25" for the other, which is ok based on previous info, and the wire diameter is .600". Where I am confused, is I thought the BB springs were a constant pitch, where these are not, and it is tough to tell from the pictures provided from others. I've enclosed a pic of my springs and took measurements from the left edge and get the following dimensions for the pitch for each complete wind of the spring. The dimensions are Left side to the pitch of the 1st wind 1 1/16", to pitch of the 2nd wind 2 3/8", to the pitch of the 3rd wind 3 3/4", to the pitch of the 4th wind 5 1/16", to the pitch of the 5th wind 6 1/2", to the pitch of the 6th wind 8", to the pitch of the 7th wind 9 1/2", to the pitch of the 8th wind 11 1/8", to the pitch of the 9th wind 12 3/4", to the pitch of the 10th wind 14 7/16", to the pitch of the 11th wind 16 1/8", and to the pitch of the 12th wind 17 1/16", and a free length of 17 5/16" (17.31"). Does this seem to make sense? If any of you could measure your nos springs or good used to confirm or deny, I'd really appreciate it. Thanks!

[Bill M.]

Re: 67 Big Block Front Springs

The reason for my inquiry is, I bought a pair of used 250 springs and still am unsure if these are proper or not. The free length is 17.31" for one and 17.25" for the other, which is ok based on previous info, and the wire diameter is .600". Where I am confused, is I thought the BB springs were a constant pitch, where these are not, and it is tough to tell from the pictures provided from others. I've enclosed a pic of my springs and took measurements from the left edge and get the following dimensions for the pitch for each complete wind of the spring. The dimensions are Left side to the pitch of the 1st wind 1 1/16", to pitch of the 2nd wind 2 3/8", to the pitch of the 3rd wind 3 3/4", to the pitch of the 4th wind 5 1/16", to the pitch of the 5th wind 6 1/2", to the pitch of the 6th wind 8", to the pitch of the 7th wind 9 1/2", to the pitch of the 8th wind 11 1/8", to the pitch of the 9th wind 12 3/4", to the pitch of the 10th wind 14 7/16", to the pitch of the 11th wind 16 1/8", and to the pitch of the 12th wind 17 1/16", and a free length of 17 5/16" (17.31"). Does this seem to make sense? If any of you could measure your nos springs or good used to confirm or deny, I'd really appreciate it. Thanks!

The top spring is a 388250 (BB w/o A/C); variable pitch
The bottom spring is a 3888251(BB w A/C); constant pitch
Your springs are 3888250

[Timothy B.]

Re: 67 Big Block Front Springs

Dale and Bill,

Thanks for the information on the springs, sometime this week I will get them out and measure the wire diameter and free height and report back. These are production run springs, I removed them from a 68 because I had to have those stiff 518 springs and am glad I didn't throw them away.