65 front springs

[Bill W.]

what is the difference between a 65 small block front spring # 3851100 and a std. 65 BB front spring # 3888250 . The assy. manual does not show the 3888250 .

[Duke W.]

Re: 65 front springs

Detailed spring specs are in the '65 AMA specs that are a free download from the GM Heritage Web site.

Duke

[Bill M.]

Re: 65 front springs

what is the difference between a 65 small block front spring # 3851100 and a std. 65 BB front spring # 3888250 . The assy. manual does not show the 3888250 .

The only difference is that the 3888250 is wound longer. 17.35 vs. 16.88 free height (this is from Chevy drawings).

[Wayne M.]

Re: 65 front springs

what is the difference between a 65 small block front spring # 3851100 and a std. 65 BB front spring # 3888250 . The assy. manual does not show the 3888250 .

Bill --- I'm glad someone has mentioned this. Neither the '65 AIM, nor the '65 and '66 P&A30 parts catalogs show the existence of a 3888250. First appears in the Oct 1 '66 version (ie. 1st issue) of the 1967 parts book. I don't know what the '66 AIM shows.

All the magazine road tests of the new 396 show a car that sits low in the nose.

[Joe L.]

Re: 65 front springs

what is the difference between a 65 small block front spring # 3851100 and a std. 65 BB front spring # 3888250 . The assy. manual does not show the 3888250 .

Bill------


I don't think the 3888250 even existed when 1965 Corvettes were being built. I think it was first used for the 1966 model year and may not even have been used at the beginning of that model year.

[Duke W.]

Re: 65 front springs

The first time the ...250 spring shows up in the AMA specs is '67. Maybe '65-'66 big blocks used the same ...100 front springs as small blocks, which is news to me.

The ...100 80 lb/in wheel rate would drop the front ride height close to an inch on a big block relative to a small block. The longer free length of the ...250 spring would return front ride height to about the same as small blocks. It would also reduce the rate slightly, but the specs say it's the same as the 100. Both use the same wire diameter and have the same OD.

Duke

[Joe L.]

Re: 65 front springs

The first time the ...250 spring shows up in the AMA specs is '67. Maybe '65-'66 big blocks used the same ...100 front springs as small blocks, which is news to me.

The ...100 80 lb/in wheel rate would drop the front ride height close to an inch on a big block relative to a small block. The longer free length of the ...250 spring would return front ride height to about the same as small blocks. It would also reduce the rate slightly, but the specs say it's the same as the 100. Both use the same wire diameter and have the same OD.

Duke

Duke-----


1965 L-78 definitely used the same 3851100 spring as small blocks. The 3888250 spring was first used for the 1966 model year big blocks but, as I mentioned, it may not have been used from the start of production. I believe the 3888250 was used to retrofit 65-66 big blocks originally equipped with the 3851100 if owners complained about low front ride height.

[Mike E.]

Re: 65 front springs

The ...100 80 lb/in wheel rate would drop the front ride height close to an inch on a big block relative to a small block.
Duke

Here are a couple of shots that might show that. First a small block from a GM promotional photo from Wayne's collection and the second is 396 from a Car Life article in 1965. There does appear to be a slight difference in ride height.








Mike

[Bill W.]

Re: 65 front springs

Joe I measured my original 65 BB springs . They measured about 16 1/2 . thats what I would expect for a almost 50 year old car . The previous owner did have 2 of the old twist in spring spacers installed .