I have the remnants of both boots on a 57 GMC Big Bolt with the sm420. They are torn and hard as a brick, but you can tell what they were originally.
The e-brake is a rectangular hole, rounded at the ends, But I think I can cut the corners circular on the one he found on Classic Parts USA. I ordered it anyway.
My original shifter boot was a big rectangular rubber boot with an aluminum plate. Gonna try one from Summit Racing or one of the round boots for a pickup.
