When I did the first mods to my car (hotcam, springs, and roller rockers) we installed the Crane 10308-1 but did not have the heads machined. I am in the process (almost 4 years later) of installing a 383 and am getting ready to have the ported heads assembled. The springs physically fit on my old untouched/unmachined stock heads. My question is was the machining to have the springs sit perfectly flat or was it so they would physically fit. The person I spoke with at Thunder Racing seemed kinda shocked when I told him they were installed with no machining. I also had them installed on another set of heads when I rebuilt them.

Joe

 

When heads get machined it is mostly for bigger diameter springs.I am using the same springs as you and no machining was/is required.

Rob.

 

no maching was necessary on your stock heads for the Crane PN 10308-1 Spring Kit which includes Crane PN 99893-16 Springs. They come with shims which all fit perfect. I called Crane before purchasing mine and recommend you do the same just to give your mind some ease. By the way these springs are awesome, they are good to 0.710 Max Net Lift with .060 clearance, lot of potential with the right cam and rollers.

 

Thanx for easing my mind guys! I just purchased a new set (mine had about 35k miles on them) for insurance and that way I don't have to touch the motor until I pull it. I hate having to pull a motor....remove something and then have to wait for the machine shop! hehe

Thanx again

Joe

 

They fit fine with no machining....only thing I would suggest is using an ID cup instead of the shim.

 

Exactly. It seems that eventually after time those springs could walk around on the shims and cause some problems. I went ahead and had my heads machined and had spring seats installed just to keep my self from worrying. It didn't cost much money and I figured with what I had spent it wouldn't hurt for a little insurance.

Michael

 

I used the crane 10308 on heads that have never been off the car and they work great. Great springs for $139 and no machine work.