Comp Cam 1

Hi all, I am in the middle of a frame off. I saw a post about someone having a possible delamination problem. I am going with a bigger than stock exhaust so, I will be closer to the current composite rear spring. I have heard that Mushegon Brake sells a steel replacement one. I will be going with the KYB GR2's (shocks) and am curious what would be a good spring weight to go with in a steel leaf? I believe but am not 100% I was running the 300lb composite spring? What are the pros and cons on a steel leaf Also a decent spring weight for loooong weekend drives?
Thanks Mark,,,,,(Sixty4)

Scott333

I have been investigating this same subject, and I recently found the following article that you might be interested in:


Composite vs. Steel Rear Leaf Springs
http://www.duntovmotors.com/Composite-vs-Steel.htm


Good luck

macdarren

I personally like the composite and have used variations of them for years with no de-lamination issues. -- I also run a slightly larger exhaust and you are correct things can get tight around the spring but the exhaust can be bent to give some clearance and also insulated to keep heat away from the spring.... That said they do ride differently, and you need to get the shocks and springs to be well matched. I push my car harder than some both on the street and weekend solo events and have several handling tweaks. I run a 360 lb composite spring and it rides decent on a decent road but if you get a rough or uneven road it stays planted but it is not pleasant. I would say 300lb is pretty close to what you want if an all around decent ride and more modest performance is your goal, if you actually want a more cruiser ride I would try to go even lighter, again with the correct shock rates. Also if looking for a steel spring I bought the one I have from Global West. They specialize in handling improvements (most for mustang) but they do do some corvette stuff. Also Check out Guldstrand Engineering, they too prefer steel.

ctjackster

mmm, well for exact repro 9 leaf springs for your 64, Eaton is the place to go. Eaton linky Since you have already chosen your shocks (a little backwards, methinks one usually matches shocks to the spring, but it can work in reverse too, I guess) then I would suggest checking the characteristics of those shocks against the oem shocks that the oem rear spring works well with.

I can report that the Bilstein Heavy Duty shocks work very well with the oem spec rear spring (I have one from Eaton on my 65) and that seems to be the view from others as well. The Bilstein Sports (I had those too) give a pretty harsh ride with that spring, if I was on a smooth track I would prefer it but not so great on the roads I drive on. If your KYB GR2 shocks have specs that match up with one of those two shocks, you can draw the same conclusion.

macdarren

ctjackster,

Any idea what the spring rate is on your vehicle. I ask because I do have the bilstein shocks both the heavy duties and the sports and also find them as you describe, good on the track not as fun on the street. Just curious how the spring rates compare to the 360lb I have. Also I am curious I thought the factory spring for these cars was a seven leaf, but I never claim to be know for sure...maybe it was an option? Maybe I will go count mine again it has been years since I looked at the original part. My car too is a 65 327/365HP #102033.

ctjackster

standard SB suspension was a 9 leaf spring; F40 / F41 got you a 7 leaf spring. Seems backward, I know. If you have what you believe to be the original suspension on there, and it is 7 leaves, it is certainly possible your car came with the F40 option (front and rear suspension), or perhaps some prev owner "upgraded" his suspension to the hi-po version (I know I might have done that back in the day). If you like it, great. If it seems harsh, even with the Bilstein HDs, then perhaps try the oem ( leaf rear spring - but if you really do have the F40 option, that will leave you with mis-matched front suspension (which would be heavier springs).

I will try to pull rate, load and free arch specs from Eaton for the spring they provide for the C2 application.

Kensmith

I have a 65 coupe with SB also. I have the VB&P 330# spring and tested it with 3 different shocks. Bilstein Sports were stiff, Bilstein HD's were too soft, then I tried the KYB GR-2 specially valved from VB&P, they were between the Sport and HD but still a little soft in my opinion so I went back to the Sports. With a 360# you may like the KYB GR-2 from VB&P. If you want more info, PM me. I did a rebound test.

JohnZ

The original 9-leaf spring rate was 140#/inch, and the 7-leaf F-41 Heavy-Duty spring rate was 305#/inch; both ratings were specified at design load of 1360#.

StrayDog

Just adding my 2 cents & what worked for me...........approx 5 years ago installed as winter project 330 lb TRW design composite spring from Muskegon brake........... MY 66 is a BB & has aluminum heads,& side exhaust & entirely new suspension components, BF Goodrich G sport tires.

Experienced no apparent bounce ( Monroe radial tuned shocks since 1996 )...... untill installed new foam & seat covers now notice slight bounce the foam has me sitting about 3" higher ............will be ordering a set of vette brakes specially calibrated rear shocks for composite springs....... have had no problems with my composite spring , worked for me rides & handles great............... The Dog

Dave64

So, Guys. Not having ever ridden in a midyear with the 7-leaf, F40-type suspension, how hard a ride is it compared to the standard 9-leaf suspension? Would it compare, somewhat to a C5 standard suspension car, or maybe a C5 riding in the SPORT position of the ride control? Thanks for any info you can pass-on.

Dave