.... can some one help me with my arithmetic? It took me 4 years to flunk algebra, yet had a successful career starting as a draftsman, and finally a life time career as a power plant engineer. Hmm...
I am leaning towards the 18.125" length jobs ....... ws
Wes, I always enjoy your posts! You have a great way of adding humor to the day!
Now for the serious stuff....
The 18.125" free length isn't the only critical spec, the spring rate needs to be considered.
This explanation is over simplified, not exactly accurate, but will get the point across.
I'll use the Moog 5230 (Special) and 6033 (GS) springs as examples.
1) The Moog 5230 has a RATE of 264 lbs/inch and a free length of 18.12".
It's designed to support 1884 lbs to produce an installed height of 11" for the spring.
You can compute ballpark height by dividing weight (1884) by rate (264) to determine how much it will compress:
1884/264= 7.136" of compression.
Subtract that amount from the free length (18.12") to get installed height of the spring:
18.12"- 7.136"= 10.984"
2)Compare to the Moog 6033 spring for the GS
Rate= 369 lbs/inch
Free length= 16.4"
Designed weight for 11" installed= 2005 lbs....
2005 lbs/369 rate = 5.43" of compression.
Subtract from the free length=
16.4" - 5.43" = 10.97" installed height of the spring.
Swap the weights so you have GS weight on a base Special spring and vice-versa:
2005 lbs/264 rate= 7.59" of compression
18.12" free length - 7.59" compression = 10.53"
and vice-versa, Special weight on a GS spring):
1884 lbs/369 rate= 5.106" of compression
16.4" free length - 5.106" = 11.29" when installed.
This shows a difference of 0.76" in
installed height between big block on small block springs and vice versa.
RIDE HEIGHT DIFFERENCE will be more due to geometry issues..... the spring (installed height) is inboard of the wheel. The wheel is outboard of the spring, so the change will be more.... a SWAG puts it at about double....so figure a 1.5" difference in ride height between the two spring/weight combos.
Laura at Springs n Things could calculate it exactly for you, or maybe there's an online calculator somewhere.
With all that said, I put some worn GS springs in my Special with 300 and 5 speed and the ride height was just about perfect. I'd give Chuck's springs a try.
And remember tire size affects ride height and stance!