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Old 04-18-2025, 05:23 PM
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Default 2nd Gen Firebird Measurement

I got the 2" drop rear leaf springs from Detroit Speed. I finally got the car on the ground and it doesn't look much different than stock ride height to me. Maybe it's an optical illusion from the short tires??

Anyway, if a few of you would be so kind as to measure your 2nd Gen's from axle centerline up to fender lip, so I can compare. See attached picture. Mine measures 16"

Thanks in advance!

Eric
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Old 04-18-2025, 06:29 PM
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Car is still away, but this is the stock ride height as measured from the underbody, out of the 76 assembly manual.
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Old 04-19-2025, 10:36 AM
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I don't normally measure from the center cap up but understand why your are. The white car is all original low mileage. The blue one seems to sit correct. The white car has a 235/60 the blue car a taller 255/60.... Hopefully these pictures are helpful.
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Old 04-19-2025, 11:31 AM
Tellyshavilli Tellyshavilli is offline
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My 70-73 rear measurements from ground to wheel well lip are around 27 1/2 to 28 inch. Those measurements are from TAs with original springs.

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Old 04-19-2025, 01:33 PM
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For my second gen (1976) I used the Hotchkis Sport Suspension Lowering Leaf Springs Package - 2409C designed to lower 1.5 in. With the OEM rear leaf shackles my wheel center to fender was 14.5 inches. On dips etc. my exhaust was hitting the road a lot. In the pictures my spacing is now 15.25 inches. I raised the car 0.75 inches by fabbing up longer shackles (the difference in the shackles isn’t even obvious and still tucked under. Not like those foot long shackles of the 70-80s LOL.) Running 285 40 18.
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Old 04-19-2025, 01:37 PM
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Mine seems to match Paul's measurements.

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Old 04-19-2025, 01:50 PM
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Quote:
Originally Posted by 76TA462 View Post
For my second gen (1976) I used the Hotchkis Sport Suspension Lowering Leaf Springs Package - 2409C designed to lower 1.5 in. With the OEM rear leaf shackles my wheel center to fender was 14.5 inches. On dips etc. my exhaust was hitting the road a lot. In the pictures my spacing is now 15.25 inches. I raised the car 0.75 inches by fabbing up longer shackles (the difference in the shackles isn’t even obvious and still tucked under. Not like those foot long shackles of the 70-80s LOL.) Running 285 40 18.

Nice looking car!

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Old 04-19-2025, 02:11 PM
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45 years of ownership and changes, and still having an awesome time with it. Thanks.

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Old 04-19-2025, 03:09 PM
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Thanks for all the replies. That tells me a lot.
I need to look into those Hotchkis springs....sounds like they may be better for road courses than what I have now.

Eric

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Old 04-19-2025, 04:50 PM
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Eric have you looked a Landrum? ..... We used a lot of the springs for drag racing and they worked great. They also made us several pairs of "custom" street/strip springs. I believe their specialty was circle track.

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Old 04-19-2025, 06:17 PM
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I'm running a five leaf spring assembly that was designated for the 1975 Chevy Nova police suspension option. No special additional curvature, just a stiffer rate.

Distance from axle centerline to wheel opening lip is 15.75"
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Old 04-20-2025, 08:04 AM
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Quote:
Originally Posted by jpg69bird View Post
Car is still away, but this is the stock ride height as measured from the underbody, out of the 76 assembly manual.
I measured my rocker panel height last night. I'm right at 8" so that double confirms all the other observations. I have "2" drop" springs and tires that are 2" shorter than stock and I'm only 1/2" lower than stock. Grrrrrr.....

Thanks....everybody was a big help.

Eric

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Old 04-20-2025, 10:47 PM
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This is for your road race second gen, correct? They are a bit spendy and I don't know your budget, but I'd talk to Global West about their Cat5 leafs.

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Old 04-21-2025, 09:37 AM
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PTFB has some nice 1.5-2" drop springs, priced better than the other big suspension companies. I have had them on my 72 firebird along with some of their other parts, been in use for 10+ years & sits very nice, lower than my stock other suspension 2nd gens using factory size tires at about 27-27.5" tall.

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Old 04-22-2025, 10:56 AM
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Eric

Your post got me to go measure my wife's '72 Camaro that still has the original 53 year old leaf springs in the back. 13.5"! My short (25.7") 275/40/17's fill the wheel well as shown in photo below.

I've been contemplating getting new rear springs to alleviate the rear end sag, but have been hesitant on what springs to get to lift the rear .75 - 1" in the rear.

Front springs are 2" drop Eibach coils installed back in 2001.

I talked to PTFB and he thought their GT Pro leaf kit springs would be my best bet and they come with shackles that have two positions to give me easy adjustability if I needed more lift:



I might cheap out as I need to replace the 7 year old tires this spring anyway. Currently running 275/40/17's (25.7") and go with 255/50/17's (27.2") to get the .75" that I'm looking for. Fronts are currently 235/45/17's (25.3"), but looking at 245/45 or 225/50/17's this time to gain maybe .25" up front.

Speed bumps and highly crowned rodes are a b!tch....
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Old 04-22-2025, 01:56 PM
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These are 235/55R17 with what should be, stock height springs on mine.
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Old 04-22-2025, 03:46 PM
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When I obtained a copy of the AMA specifications for my 1970 2nd Gen they stated this as the factory ride height. These are height dimensions from the rocker panel to the ground in two places. The forward point on the rocker panel is located 36.3 inches from the front wheel centerline and it is supposed to be 6.5 inches off the ground. The rear point is 16.1 inches from the rear wheel centerline and is supposed to be 5.5 inches off the ground.


.

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Old 04-22-2025, 04:21 PM
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Quote:
Originally Posted by Steve C. View Post
When I obtained a copy of the AMA specifications for my 1970 2nd Gen they stated this as the factory ride height. These are height dimensions from the rocker panel to the ground in two places. The forward point on the rocker panel is located 36.3 inches from the front wheel centerline and it is supposed to be 6.5 inches off the ground. The rear point is 16.1 inches from the rear wheel centerline and is supposed to be 5.5 inches off the ground.


.
Did it indicate the tire size for that? Seems a bit low, but considering that might be the spec with the base F78/14 tires, then correct.

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Old 04-22-2025, 07:53 PM
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Quote:
Originally Posted by Elarson View Post
I got the 2" drop rear leaf springs from Detroit Speed. I finally got the car on the ground and it doesn't look much different than stock ride height to me. Maybe it's an optical illusion from the short tires??

Anyway, if a few of you would be so kind as to measure your 2nd Gen's from axle centerline up to fender lip, so I can compare. See attached picture. Mine measures 16"

Thanks in advance!

Eric
Have you driven it some to settle those new springs?

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Old 04-22-2025, 08:16 PM
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Quote:
Originally Posted by jpg69bird View Post
Car is still away, but this is the stock ride height as measured from the underbody, out of the 76 assembly manual.
Quote:
Originally Posted by Steve C. View Post
When I obtained a copy of the AMA specifications for my 1970 2nd Gen they stated this as the factory ride height. These are height dimensions from the rocker panel to the ground in two places. The forward point on the rocker panel is located 36.3 inches from the front wheel centerline and it is supposed to be 6.5 inches off the ground. The rear point is 16.1 inches from the rear wheel centerline and is supposed to be 5.5 inches off the ground.
.
There's a pretty big discrepancy between the numbers in these two posts. Below is what I found in my 1970 assembly manual. The car they show is a 1st gen but if you look in the bottom right area of the page it says it's for 1970.


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