How to Chop the Top on a Custom 50’s Pontiac
The first day of any major chop, channel or section project will surely see the largest turnout of “help”. Everyone you know will want to comer and be a part of something that could go one of two ways. First, they could say “I helped build buddy’s totally bad-ass, chopped-top Pontiac” a truly noble thought and they even have a little ownership in the project. Second option, they could get a front row seat to watch someone really destroy their car. Lets hope we have none of the latter, but its always a distinct possibility. You will need to have the vehicle as stripped down as possible and all of the areas you are welding as clean as possible. You don’t want anything catching fire like interior, gaskets or window seals.
Some things you will need on hand for this:
1 – A welder; a 110 MIG is perfect for quick and dirty tack welds to hold stuff in place.
2 – A reciprocating saw (Sawzall) for making gnarly rough cuts
4 – a cutoff wheel with a 4″ or so cutting disc for precise, clean cuts
3 – a bunch of cheap 3/4″ conduit from the harware store – I’ll get to this soon.
Start out by getting the doors in place so all of the cuts are consistently spaced. The idea here is to set the door gaps as close as possible so when you weld everything back together you don’t have other alignment issues show up. The driver side door here was badly sagging, so we lifted it with a jack and tacked the doors shut both above and below the cuts. This ensures that nothing moves when sparks start flying. (See photos)
Next weld bracing to strengthen the roof AND to strengthen the body. This is very important: you need to have separate cross x-bracing and side-to-side bracing above your cut area and below your cut area. When you make the cuts you don’t want the roof to still be stuck to the body because your bracing crossed across the cut. The bracing is very important though because these large vehicles are very dependent on the roof as a structural member. Once it is removed everything will spring apart like a can of snakes. Welding the roof bracing is also nice because it allows you to safely remove and replace the roof as a unit without fear of distorting it. Carefully tack all of the bracing without over-welding, you want to be able to cleanly remove these when the chop is complete. Remember these are temporary welds but still need to be strong.
Once everything is tacked in place, the bracing has everything supported you are ready to lay out the cuts with tape.
If you have questions, ideas or would like a quote for building or chopping your own car please feel free to email me any time with the contact form on the sidebar. I will gladly quote full builds or complex one-off parts to assist you in your build. I’m here to help so lets go!
