With the big difference in spring rates between 1984 and 1985 Z51 Vettes I find it strange that there is no specific 84 Z51 shock listed by Bilstein.

Is it correct that from the factory it the 84 & 85 Z51's come with the same shocks? Anyone have access to part #'s from back in the day?

 

I know in 85 the Spring Rates changed and the sway bars changed to compensate, I thought I read somewhere the Bilsteins were added in 85 but not sure, maybe in 84 the shocks were the same for Z51 and non and then in 85 the 2 different options had 2 different shocks?

Dunno.

From everything that is out there I think though the Z51 shocks on the 84 and 85 would have been the same.

 

The thing is, in 85 the spring rate options were

FE1 54.0fr 39.9r
Z51 63.5fr 57.2r

These two spring rates called for 2 different shocks FE1 (Standard) and Z51 Sport

The 84 Z51 spring rate is radically different at

Z51 102.0fr 87.5r

 

Could PM Dave (WVZR-1 )

He always seems to be able to pull OEM factory part #'s out of the hat

 

Hey "OZ" - Happy New Year

OE shocks for the '84 were a single year "only" and there were only two applications: 1. base 2. F51 HD option. Those "service part numbers" never carried forward to any other year for "service". I'd guess an NCRS project would require the appropriate numbers stamped into the shock.

Later "service parts" did actually include '84 applications into their guides but you need to remember that these are "service parts" not production.

I've always thought that Bilstein wasn't available prior to '85 and that's why I'd expect that you would seldom/ever see an '84 specific application in application guides.

I've always thought that there's misconceptions as in this post where people post "Z51 shocks" - Z51 was a package/sales option which included several HD options

I believe that on "any" SPID label where a Z51 RPO is referenced you'll also always see a suspension and shock option referenced as well as RPO's for the "rest of the package".

Correct F51 shocks for an '84 I believe would carry stampings that matched the sales number 4993596 front, 4993597 rear.

Like I mentioned Z51 is NOT a "spring" but a package. FE7 would be the correct reference used to describe the "spring rates" for the years you mention.

 

Hey, thanks for the information. Your right the Z51 RPO was nothing but a package that called for other specific performance RPO's including the FE7 Sports Suspension. I know that Z51 always included FE7 but could you add FE7 to a base Corvette?

Interesting to see that the shock manufactures seem to ignore the big spring rate difference between the 84 and 85-87. I just want to find some shocks that are properly matched to my 84 FE7 springs.

 

What shocks do you have presently?

Yes I believe that if ordered FE7 could be have been done as a "stand alone" RPO. The kicker is though that during production there could have been restrictions placed and FE7 if there were parts shortages could have been restricted to the Z51 package.

 

Interesting. My 84 Z51 had Bilstein shocks on it.

I had always assumed they came on the car from the factory. It only had 101K miles before it was made into a race car and everything else on the car was dead stock.

I still have the rears off the car sitting in my garage and could get the numbers off them if you wanted. The fronts are still on the car but I will have the car back from the chassis shop Jan 17 and could check their numbers after that.
Will

 

Hey Will - that would be interesting information. I'd be interested for sure. If I could ID the rears then possibly the front information could be "assumed" and then you confirm that when the car returns.

Assuming that one of the PO's was attempting to "soften" or "cure" the Z51 ride I wouldn't be surprised to see a shock replacement.

 

My bilsteins have number if interesting stamps on them all near the shock eye on the cartridge.

220 247 39

3270231W00

BILSTEIN (inside a square box)

MADE IN WESTERN GERMANY

There is also a white sticker with the code "GV" and the normal chrome Bilstein sticker and caution oil under pressure sticker.

Will

 

As did mine, bought as 2nd owner with 11000 miles and original Bilstein shocks in place. This white coupe was a virgin.
It also has the oil cooler.

Later in the game, I had them rebuilt/revalved by Bilstein to Challenge specs, which greatly improved the ride.

The stock Z51 was reportedly the roughest riding Corvette ever, capable of exceeding 1G lateral, for press and track purposes, but it received many complaints about the ride.
Thence, it was softened for '85, hence different springs.

 

The 22024739 hints that its an OE shock only because you have the GV label on it.

Now if someone with the build sheets for an '84 I believe the shock codes likely appear in block 17 & 18. If there are folks with Z51 builds '87 and earlier it would be interesting to see the codes in those blocks. I fairly confident on the block numbers but I don't have a build sheet here to check. The blocks would be ID'd by FRT Shock/RRShock

 

I've used the Bilstein rebuilding service for a number of years now. They can take your Bilstein shocks and rebuild them to your car. I had to have mine done over when I switched to the Hyperco Corvette Challenge springs.

Here's an article I wrote last year about shocks.

Richard Newton

 

The question here is NOT the serviceability of the Bilstein BUT if they were maybe OE for an '84. Most press documents and other "articles" seem to imply '85. What is needed here is for owners of '87 and earlier who have NCM "build sheets" post the information in block 17/18 with shock codes to see if the GV code is actually there.

Here's an '89 "build sheet" that displays in block 17/18 the information needed but for '84, '85, '86, '87 and maybe both FE7 and base suspension builds. All Z51's would include the FE7 but it wasn't I believe a required purchase to obtain the FE7.

http://forums.corvetteforum.com/1581546965-post2.html

 

Oh my. Twas useful info, to some.

I am hardly motivated by the tone, to check my sheet. My 1984 Z51-equipped Corvette came with Bilsteins, stock, which is exactly what I remember was part of that package. There IS no maybe.

Cheers.

 

Sorry you "assumed" a "tone"!

There's conflicting information all over the place and this seemed like "maybe" the place to "sort it". There are Corvette "sites" that quote an FG3 shock for an '84 and go so far as to post production #'s and price, one of those sites also shows 1/2 of '84 production to be Z51. I'd say that's interesting.

I believe it's more likely that a Z51 in '84 would have a F51 option for shocks which is only noted as HD and NOT "gas". Were they actually? GM acknowledges the FG3 (gas charged) as becoming an RPO in '85 not earlier, a later GM SPO publication shows an FG3 application for an '84. Was the FG3 an actual RPO for the '84? Build sheet confirmations would be the only confirmation. Was the FG3 an option over and above the Z51? I've never seen it mentioned.

I would think it might interest you. An '84 Z51 if it carried also the FG3 might be a more conversational build. I've seen posts where '84 Z51 owners mention the F51 but I don't believe I've seen anyone claiming the FG3 RPO. How about taking a look?

In your SIG you mention "Elec HydroBoost" - that interests me greatly and I would think also most participants.

 

The websites info appear to be taken from the "Corvette Black book". A book of reliable production data taken from gm records. Reliable enough to be sold by the NCRS. The fg3 shocks was a stand alone option for 84 and sold at 3729 units. I would hedge a bet the fg3 option showed up as a mid to late 84 introduction. This would explain the low build quanity. Going off of memory as I dont have access to the book right now but I believe Dave Mcclellan discussed the 84 and the bilstein shock introduction in his book "Corvettes on the inside". I seem to remember something about it making the 84 z51 ride much more compliant then when fitted with the delco shocks.

 

That is precisely the reason for my question regarding build sheets. I could understand the possibilities for late introduction but it's so frequently stated and assumed by '84 Z51 owners that it was part of the build. I'm somewhat curious as to whether it was or not. I doubt it was with ALL production. Maybe when if it were a mid-late year addition. I've seen F51 builds but I've never seen an FG3 build.

The most frequently suggested "adjustment" to the rough ride complaints was the lowering of air pressures from 35 to maybe a 26 number.

A build sheet that displayed FG3 and the same shock code as "rklessdriver" posted would confirm that. The OP's question was "why isn't there?" and it seems through what I've seen is there may possibly have been, I have a GM replacement progression for what might have been and ultimately the GM service FG3 shocks all were finally serviced with the same SPO numbers until discontinued. That's why the "advertised" Bilsteins are featured as all Z51!

Just need some '84 thru '87 Z51 build sheets.

Your reference to NCRS could go something like this and we've all seen it. Deducts for inappropriate original equipment - then it becomes the owners "duty" to prove his argument. I've never seen an '84 NCRS manual but that might be an interesting "adventure" also.

*** I seem to have found an '84 Dealer order option guide and there does seem to be an FG3 option but there's of course no mention of I being "included" with the Z51. That order sheet doesn't seem to reflect the F51 HD option though.

 

In 85, Bilstein fg3 was standard with z51 and optional on base suspension models. Fg3 was only available with z51 in 84 as an option. It had to be ordered or the delco HD shocks were installed. This is shown by the quanity of z51 to quanity of fg3 and fg3 in 84 being restricted to z51 and it cost. When it was available you and I would like to know. But post 85 its is well known all z51's had bilstein shocks. Its listed in print as standard.

 

I'm jumping in here late, but I have an 84 manufactured 1/84. It had black Delco HD shocks when I bought it and I didn't get to the build sheet, but the codes in the storage bin are:
Z51 Performance handling package.
F51 Heavy Duty shocks
FE7 High performance suspension
I replaced the shocks with the Bilstein listed for cars with Z51 and it made a huge difference -but to be fair the Delco shocks had 88k miles on them.