72455

Hey all I'm getting a plan together to replace the front coil springs on my 72 Supreme and I need some direction.

I have the U code 455 and the car was originally equipped with A/C. A PO removed the compressor and the lines when he set the car up for drag racing.

I dunno at this point if I'm going to replace the A/C parts, but just in case, I'm not sure about the front coils, so here's my thought process:

I know the coils are different between the A/C and non A/C cars, and correct me if I'm wrong, but aren't they also different for the 350 engine? I want a decent ride, but as I said, I dunno if I'm going to replace the A/C, so in case I do, I don't want to replace the springs again. So do I go with the springs for a 350 A/C car as a compromise, do I go with springs for a non A/C 455, or do I go with springs for an A/C equipped 455, and if I go with the latter, what will the ride quality be without the A/C?

Thanks,
Dave

Fun71

Yes, there are different spring numbers for BBO vs SBO, AC vs, no AC, heavy duty suspension vs. standard.

A lot of what you are asking depends upon what ride height you want to end up with.

So you need to measure the current ride height and determine if you want the same, higher, or lower. Then determine if you want a softer ride or a firmer ride.
After all of that, you can choose the spring that gives the ride and height that you want.

72455

Thanks for the reply...I'm looking for stock ride height with a ride somewhere on the middle of soft/firm.

Fun71

Here's some MOOG spring info I archived a while back:

72455

Thanks for posting this chart. It shows a 72 Supreme 455 on the first line and also on the 7th line, both with different spring rates, so which one?

Also, I plan on going with stock ride height. Would the ride be that much different with 455 A/C coils vs. non A/C 455?

Thanks.

Allan R

Dave,
Just my opinion but I'd go with the Moog 5450 (with AC). The only components of your AC that are missing are the compressor and mounting brackets. They weigh in at about 60-65 lbs. Not enough of a difference to warrant going with a lower sprung mass. BTW, changing the front springs is an adventure in itself. Has the front end been upgraded with new bushings (upper/lower control arms), ball joints and sway bar bushings? Is there any play in the steering that warrants looking at replacing the inner/outer tie rod ends or center link? Once you start it seems like it never ends.

truckman5000

I have 1in lowering springs and a body hotchkiss shocks, huge improvement and height same as the old 40yld springs

72455

Steering is good as are the tie rods, and I replaced the idler arm soon after I bought my Cutlass.
The PO said the front springs are bad, but before I do anything, I'm having it checked at a shop that knows vintage iron.

Allan R

Dave, what information did the PO give you except he thought they were bad? There is a ride height setting in the Assembly Manual on page 27 (section 0) that gives the points of reference from the rocker to the ground. Is the ride too mushy? That could easily be shocks instead of springs.

72455

The ride seems fine Allan. Not too mushy but not too harsh either. I was only looking to replace them based on the PO info. I'll check the ride height later today and post the results.

72455

I don't have an assembly manual, so I used the chart below from the CSM. I don't know if I have heavy duty suspension, but I measured 10 inches at the point of reference as shown in the chart.
Thoughts?

Allan R

Sounds like your ride height is spot on. I don't think I'd change anything right now.

72455

Gotcha...thanks Allan.