[dataway]

Anyone else use all the convertible mounting bolts on their hardtop? By that I mean filling holes #1 (inside cowl location) and #4 (forward of the rear axle) with bolts and cushions instead of just the cushions?

I've already done that with #4 .. was thinking of putting a bolt in #1 while I still have the chance. Figure if it's good enough for a convertible, should be great for a hardtop.

[OG68]

I've been thinking about that too. I have the parts, but the initiative is still missing.

[dataway]

I ask because right now with my body mounts loose (waiting to fit the front clip before I tighten them) and the car up on the quick lift with the engine and all front suspension installed the frame flexes enough that I can just push the top of the mounts between the body and the frame ... won't have that opportunity again for many years (hopefully).

I don't have the parts, but Ames sells a "trunk" kit that has the same two insulators as used up front.

[dataway]

I got my two extra front bolt on insulators shoved between the frame and body without any drama.

Question .... when the typical body mount with the sleeve is tightened down, does the bottom washer bottom against the bottom of the sleeve? I haven't finally tightened down any of the mounts yet, but when I tried one I noticed it came to a full stop after compressing the donuts ... normal?

[gto4evr]

Originally Posted by dataway

I got my two extra front bolt on insulators shoved between the frame and body without any drama.

Question .... when the typical body mount with the sleeve is tightened down, does the bottom washer bottom against the bottom of the sleeve? I haven't finally tightened down any of the mounts yet, but when I tried one I noticed it came to a full stop after compressing the donuts ... normal?

yes

[north]

I did the same sort of thing on my then newish 96 LT-1 Caprice. Police cars (but not Impala SS or regular Caprices) used bolts in the exact same position where other models just used cushions. The 77-96 B body frames were basically the 73-77 A body 4 door 116" WB frame so it was almost deja vu going under the 96. What made it easier on the 96 was that they used open cushions regardless while back in the 60's the unbolted cushions were blind. Interestingly the 68-72 Olds and Buick A body coupes do use a bolt in position 4 (the chevies and Pontiacs don't), pecking order I guess.

My Caprice felt tighter after I added the 4 bolts but was it real or imagined?

[dataway]

I don't think it was necessarily imaginary ... I've got my car up on a Quick Jack so the whole front end, engine installed but not the fenders, bumper ... is hanging off the front supported by the quick jack just behind those bushings. With just the one bolt installed and tightened I measured from the front frame horn to the ground. Then I installed and tightened the additional bolt on both sides and measured again, it's did bring the frame up about 1/8" ... so it was basically using the body (hardtop) to stiffen up the frame. Not sure if that would translate into more stiffness with the wheels on the ground ... but I can only assume GM added it on convertibles and the upper line marques for a reason.

[Sirrotica]

Anything that stiffens the chassis/body assembly will make a better platform for the suspension to work better. The same reason race cars are fitted with a roll cage is twofold, protect the driver, while stiffening the whole assembly to get repeated handling characteristics.

The car reacts the same way every time with a stiff chassis. By the same token a flexible chassis will many times react differently, depending upon where the flex occurs. Ideally there will be very minimal chassis flex in a chassis. Any measure taken to minimize flex, will be an improvement in handling characteristics.

When stock cars were built from parts from the factory ,many times a convertible car would be sourced for the stiffer chassis assembly, and ease of welding a roll cage into the car without a roof in the way. After assembled, a roof would be grafted onto the car making it a hardtop.