1970 BB w/AC Front Coil Spring Question
Thread Starter
Pro
Joined: Jun 2004
Posts: 573
Likes: 3
From: Grand Blanc Michigan
1970 BB w/AC Front Coil Spring Question
I have 1970 big block with AC. And I was told(by Paragon) the correct springs for that combination(BB w/AC) was not available. The suggestion(by someone in Florida) was made to use F41 suspension type front coil springs(Part#xxxx518).
I just checked the Corvette Black Book for that type of suspension(F41), and it does not list it...... Where did this guy come up with the F41 suspension code? Anyone know?
Anyone know what replacement coil springs to use for a 1970 BB w/AC?
I just checked the Corvette Black Book for that type of suspension(F41), and it does not list it...... Where did this guy come up with the F41 suspension code? Anyone know?
Anyone know what replacement coil springs to use for a 1970 BB w/AC?
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
I think that the the F41, Gymkhana front springs were rated at 550 and the rear around 360....I think.....someone will have the exact specs.
I believe 550 would be a good choice for your BB. You can get them at VBP. Depending on your current ride hight, they will most likel lower your front by 1 inch or so.
I replaced my worn out stockers with these and it lowered my front by 1/2 inch or so. BTW, you might want to look at the rear spring as well since the 550 goes well with the 360 in the rear.
I believe 550 would be a good choice for your BB. You can get them at VBP. Depending on your current ride hight, they will most likel lower your front by 1 inch or so.
I replaced my worn out stockers with these and it lowered my front by 1/2 inch or so. BTW, you might want to look at the rear spring as well since the 550 goes well with the 360 in the rear.
Thread Starter
Pro
Joined: Jun 2004
Posts: 573
Likes: 3
From: Grand Blanc Michigan
Ken, one of the long time techs with Paragon said if I only replace the front coils with Big Block coils and not taking into account of the Air Conditioning the ride height would be noticeably lower. I do not know what to buy.....
Drifting
Joined: Mar 2006
Posts: 1,526
Likes: 2
From: Oak Ridge NC
I'm guessing that you are replacing your BB coils because they are worn? No matter what you replacement them with, your ride height will most likely be different than what it is right now. Stock ride height for an LS5 cpe was approx 27.5" front and 28.25" rear...give or take an 1/8". The front can be raised by adding a spacer under the spring and lowered by removing a coil.
First things first....what quality ride are you looking for? What profile/ride height are you looking for. Once you decide that, then decide on springs/shocks.
Here's a pic of my '70 BB with A/C, 235/60/15 tires, 26 1/4 front ride height and 27 1/4 rear. VBP front 550 coils, rear 360 mono, Bilstein vette sport shock.
You have a lot of options. Good luck!
First things first....what quality ride are you looking for? What profile/ride height are you looking for. Once you decide that, then decide on springs/shocks.
Here's a pic of my '70 BB with A/C, 235/60/15 tires, 26 1/4 front ride height and 27 1/4 rear. VBP front 550 coils, rear 360 mono, Bilstein vette sport shock.
You have a lot of options. Good luck!
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Oddly, the "correct" replacement spring for your application seems to have been pretty much overlooked by the industry. Original # 3931826 coils were 325#. But, you shouldn't shy away from stiffer springs, as the stock rate was considerably too soft to help counter roll with the extra weight of a BB w/AC, which is IMHO the overriding reason why the BB Vettes got a rear bar.
If you don't find the 550's desirable, Duntov has some long 450's that ought to do the job (#F112). Personally, I wouldn't mess with the rear spring rate until you find out where you are (balance & ride wise) from whatever change you make up front first.
Also, unless the roads on which you drive present ground clearance issues, lower ride height is a good thing. Just make sure and get both the Z & D heights (fundamental suspension geometry dimensions) on the same page.
BTW, nice looking ride SmokinBBC!
If you don't find the 550's desirable, Duntov has some long 450's that ought to do the job (#F112). Personally, I wouldn't mess with the rear spring rate until you find out where you are (balance & ride wise) from whatever change you make up front first.
Also, unless the roads on which you drive present ground clearance issues, lower ride height is a good thing. Just make sure and get both the Z & D heights (fundamental suspension geometry dimensions) on the same page.
BTW, nice looking ride SmokinBBC!
