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Will a spreader bar help prevent cowl shake in my 73 convertible ? When I run over a manhole cover or hit a bad bump the car shakes. I have the Van Steel coilover system with Ridetech shocks.The shocks are set on soft settings. I don't want to spend $20,000 on a modern stiffer frame. Any ideas? Thanks Charlie.
It's a long shot, but shine a bright light on all six body mounts to see if they are rusted badly/spacers are missing/check mounting bolts to make sure they are tight if everything else looks good.
What made a big difference on my 68 convertible was welding/closing-up the stitch welds between the wheels from underneath (since that's all I could reach).
I subsequently closed up the topside stitch welds in the engine compartment (when I had the engine out) and added a spreader-bar. Neither of those was as noticeable as closing in the stitch-welds between the wheels.
Originally Posted by 73ls1
Will a spreader bar help prevent cowl shake in my 73 convertible ? When I run over a manhole cover or hit a bad bump the car shakes. I have the Van Steel coilover system with Ridetech shocks.The shocks are set on soft settings. I don't want to spend $20,000 on a modern stiffer frame. Any ideas? Thanks Charlie.
I have #6 brace but not installed.The car has vintage air so I need to modify the brace.My 73 has a LS1 and I need to make a spreader bar that clears the lower radiator hose.
Will a spreader bar help prevent cowl shake in my 73 convertible ? When I run over a manhole cover or hit a bad bump the car shakes. I have the Van Steel coilover system with Ridetech shocks.The shocks are set on soft settings. I don't want to spend $20,000 on a modern stiffer frame. Any ideas? Thanks Charlie.
It might reduce some car rattle but I don't think it will help enough that you will satisfied. It is even doubtful you will even notice any change in noise / shakes.
The addition is not expensive enough not to try. Let us know how it turns out if you decide on the addition.
All older convertibles will exhibit cowl shake. It’s the nature of the beast with the frames and technology used back then.
Now if it’s excessive is another thing but probably something you will need to compare against a similar model.
You may be able to reduce the cowl shake somewhat with extra bracing but you’ll never eliminate it in these cars.
Just my .02
I have #6 brace but not installed.The car has vintage air so I need to modify the brace.My 73 has a LS1 and I need to make a spreader bar that clears the lower radiator hose.
Here's a thread on bracing w/ Vintage Air by "mysixtynine"
I have #6 brace but not installed.The car has vintage air so I need to modify the brace.My 73 has a LS1 and I need to make a spreader bar that clears the lower radiator hose.
here's my brace from a 1977 vette with LS1 , this is the right side mount , it was a Big Block weld it yourself kit , that just clears the bottom hose , obviously more weld was added .
I installed the speed direct spreader bar as it's smaller in diameter than the others and it clears my engine driven fan (stock fan pulley with a spacer and flex fan). It made a big difference to steering feel but I still get a little cowl shake over big bumps. Fortunately there are not a lot of those where I live and drive. That's just life with a C3 Convertible. Mines a '71 BTW.
I installed the speed direct spreader bar as it's smaller in diameter than the others and it clears my engine driven fan (stock fan pulley with a spacer and flex fan). It made a big difference to steering feel but I still get a little cowl shake over big bumps. Fortunately there are not a lot of those where I live and drive. That's just life with a C3 Convertible. Mines a '71 BTW.
where would you find that weld yourself BB spreader bar at, I have a 68 BB vert and would like to install a spreader bar
the 68s verts did not have any under dash cowl bars, that started in mid 69
I installed the speed direct spreader bar as it's smaller in diameter than the others and it clears my engine driven fan (stock fan pulley with a spacer and flex fan). It made a big difference to steering feel but I still get a little cowl shake over big bumps. Fortunately there are not a lot of those where I live and drive. That's just life with a C3 Convertible. Mines a '71 BTW.
I agree..I had the same experience with the speedirect spreader bar...BIG DIFFERENCE. If you do not notice a difference with a spreader bar than it is not installed properly or you have a chassis that was built by GM for a C3 that is different than all of us (NOT likely).
I bought the spreader bar for my 73 BB from Van Steel.
I'll be running dual spay electric fans so I should not have any interference issues with the OEM fan.
I'm running a vb&p spreader bar and plenty of clearance with my ls3 swap. In fact i had less room with the old 383 sbc and serpentine setup. Easy install. Hope this helps and good luck.