My '70 Challenger Convertible is by-no-means stock, and I'm not trying to change that. The prior owner's resto-mod "restoration" includes many non-'70 original parts, and aftermarket stuff. So I don't mind doing what I'm planning to do regarding the A-Pillar interior trim. I wanted to replace them because the plastic had cracked at the screw hole at the lower end of the piece. Several years ago, I purchased original mint condition '70-'74 hard-top pieces because I read somewhere that the top could be cut off for convertible applications (I recently read that the same thing was done at the factory). The only way I was able to get the trim off the A-pillar was to break it off in many pieces because it was "fused" to the windshield's urethane adhesive. When I placed one of the hard-top pieces on the A-Pillar, I noticed that the lower screw hole was in a different location (higher up). I was perplexed until I started doing some research here and elsewhere. I now understand that there were two versions of the A-Pillar trim; that which was used in the 1970-71 cars, and another which was used in 1972-74 cars. I believe the only differences were in the location of the screw holes and possibly the hardness of the plastic (1970-71 being harder than the later years). I'm going ahead with using the HT pieces since they're in such nice condition. I plan on drilling a new screw mount hole in the A-Pillar, and cutting the top off the trim just below the top screw hole. Any comments or suggestions on my plan and/or what tool/method would be best to cut the top off will be greatly appreciated. My other concern is whether or not I'll be able to get the drill where I need to in order to drill out the new hole (the windshield is still in and I'd rather not have to take it out and put it back in just for this). Pictures are of the two passenger side trim pieces. I lined up the Pentastar and part numbers to show the screw hole location differences. Interestingly, the part #s are the same. Thanks.

It's an easy job. Any saw will cut the plastic. The top, cut portion will be covered under the metal 90 degree corner piece.
The bottom screw does not even need to be installed. The plastic piece is held firmly in place.
But, if you would like the hole to be filled with a screw, you could just drill a new hole in the new location of the later model modified piece. Just an option.
Otherwise you will have the original later model screw hole that will be unused.
I personally would look for a 1970-71 piece, if I was going to modify it.

Actual convertible pieces are still out there for sale.

And to build on Ola's post - the original convertible pillar trim has the same moulded part number as the 70-1 hardtop trim so you will have a point of reference when you go shopping

Not to be picky and I may be wrong but I believe it is 70 only, not 70 and 71 that has the lower hole real close to the bottom.
Also if drilling another hole in the plastic try to have the hole countersunk like original so the screw tightens in and the head is not above the surface thus making it appear factory original.

I used a die grinder/cutoff wheel to cut mine. Made a perfect cut. Not sure on what the break point is for the the different screw hole locations. I was lucky and had a early style one that was broken at the top, so it was the perfect candidate to make a convertible one out of.

A related question. Should the pillar post color be black to match the black dashboard OR be white to match the white front and rear seats, door panels and white convertible top ? The car is plum crazy as pictured as above .

On my 67 BCuda pillars there is a molded in line that shows where to cut. Maybe yours has that too.

-Daty