620 coil spring question

Hello. My 65 is LOW in the front. When I got the car it had 620 coils that had been cut (and the lower Shelby control arm drop mod). I'm going to get new 620 coil springs and I have two questions.
1. How much will cutting one coil or a 1/2 coil lower the car?
2. How long does it take for them to settle, is there a way to make them settle quickly (EX.. by driving around without the shocks in and going up and down driveways, pull over check height, if still to high, cut a little more... drive up and down driveways... repeat?) I'm trying to get a specific height on the car and am worried about getting it perfect just to have it settle to low (that has happened to me before on another car). Thanks for the help.
 
I want the car to be 1/2" higher, so maybe this is the better option, I can mill the one inch lowering blocks down to 1/2" (therefore lifting the car 1/2") and then buying those thick 1" coil spring insulators from Scott Drake and turning those down to a 1/2 " on a lathe (therefore lifting the front 1/2"). Here is the link to insulators I'm thinking about

Scott Drake Store - Coil Spring Insulators (Black Polyurethane)

I think this will take all the guess work out of everything since I will be using my existing springs that have already settled. Has anyone used these insulators before? Do they go on top or bottom of the spring? Are they OK for very "spirited" driving? My car is performance orientated and I just want to make sure they will stay seated during hard driving, they should, just want to make sure. Thanks!
 

Attachments

  • C4DZ-5415-URT.webp
    C4DZ-5415-URT.webp
    4.9 KB · Views: 224
I have used the 1" insulators and they slip out sometimes. Im plan on using another set of 620's and cutting a 1/2 coil this time.I would assume its AT LEAST a 2" drop for 1 complete coil being cut.My buddies car that was next to me at Knotts had uncut coils and mine are cut and its about 2-2.5" lower
 
The rule of thumb is you get about 2" of drop for one coil cut off. Although I cut 1/2 a coil from a set of stock big block springs and it dropped the car 2". That was after I drove the car without shocks op and down driveways and over speed bumps to get them to settle and it still sat to high.
 
I want the car to be 1/2" higher, so maybe this is the better option, I can mill the one inch lowering blocks down to 1/2" (therefore lifting the car 1/2") and then buying those thick 1" coil spring insulators from Scott Drake and turning those down to a 1/2 " on a lathe (therefore lifting the front 1/2"). Here is the link to insulators I'm thinking about

Scott Drake Store - Coil Spring Insulators (Black Polyurethane)

I think this will take all the guess work out of everything since I will be using my existing springs that have already settled. Has anyone used these insulators before? Do they go on top or bottom of the spring? Are they OK for very "spirited" driving? My car is performance orientated and I just want to make sure they will stay seated during hard driving, they should, just want to make sure. Thanks!



They go on the top of the spring.
 
I believe 1/2" lower at the spring perch drops the fender to ground height 1". So possibly you need a 3/4 top spacer. I did this on my car when i cut equal amounts off of 620s, and my fender measurements where off. I trimmed one of the 1" spacers to get the gaps the same.
 
IMHO.... I believe you were on track with your first Idea, and should get the New springs. Take your time, and adjust them correctly to the height that you are looking for. The spacers are actually going to take away from the potential travel, of your suspension, and with the new springs, you'll have an added bonus of recapturing some, that's been lost. Even though it's a pain, I would install the new ones, uncut, and give them a little time to settle, than I would remove them for cutting, if that's what you want, and cut them accordingly. Generally, most would trim them a 1/4 coil at a time, so as not trim them too much........ Good Luck with your decision, and your Project.

just my .02 sense.....