Column Shifter

Recently my boyfriend and I purchased a 87 monte carlo ss. The kid who owned it before us put in an aftermarket column shifter. For some reason, probably because the kid wasn't smart, it wont stay in park and it slips out of reverse. I've looked all over the country side for an original column shifter for this car, and have been unsuccessful. Someone said you could use an oldsmobile column shifter. Any ideas?! Please help. We want to get the car on the road ASAP. Feel free to email me too

I'm not sure if you can use an Olds shifter, but i'm pretty sure you can adjust that linkage. When the previous owner installed the column, they probably never re-adjusted it.