Help�65 396 Front Springs part numbers?

[Bill M.]

Rick------


I would assume they would be the same and, certainly, if the PRODUCTION and SERVICE springs were manufactured at about the same time. However, the ones that I have were almost certainly manufactured later. In any event, there must be some sort of tolerance range on the original drawings/specifications.

In general. the tolerance on length is +/- 4% and the tolerance on rate is +/- 3%

[Rick B.]

In general. the tolerance on length is +/- 4% and the tolerance on rate is +/- 3%

Bill absolutely tremendous!!

[Joe L.]

So guys Shifting gears slightly.

3851100 SB/396s. BB HD (F40) 63-67 3832518. Thats quite clear.

Its interesting that the 63-64 had an AC (C.A.C) coil in #3833319. 66 BB had an AC coil in #3880400
and 66-67 BB had an AC option in 3888251

BUT that there was NO Coil specific for 65 AC cars? First, am I correct here or missing something?
Second any hypothesis why this clear gap in production for a 65 AC/396?

Rick------


The was no 1965 with L-78 and C-60 and L-78 was the only big block for 1965..

[Rick B.]

[Joe L.]

Yes Joe exactly in 65....But got it (little slow sorry) .......your implying when they combined the BB with AC in subsequent years GM engineering must of realized they needed a different spring. springs 400 and 251

Thanks for all you insights here...as always just great!

Rick------

For 1966 different coil springs were released for both C-60 and non C-60 big blocks. For C-60 big blocks the GM #3880400 lived a very short life having been discontinued from SERVICE in January, 1966 and replaced by the GM #3888251.

I believe the reason for the change was 1965 L-78 owner complaints of low front ride height. Some 1965 L-78 were dealer retrofitted with the GM #3888250, the non C-60 1966 big block coil spring, due to owner complaints. I expect that GM did not want to wind up with a lot of 1966 Corvette big block owners with the same complaint.