Nice score today!!!!
 

Picked up a 89 Merc Grand Marquis today for $200 bucks! Straight body, good tires, good but dirty interior, and a known overheating problem.
After getting it home, I decided to check out my new toy. Filled it with water and noted that it would overheat without the thermostat ever opening. Duh! Some idiot put the thermostat in backwards:-banghead I drove the car about 15 miles this evening and it runs and drives like a large luxury car should. Hmmmm..... tax time, looks like I might make a few $$$$$ on this one }>
It does have one slight issue though, it has a stumble just off idle and a check engine light. I haven't gotten to checking this out yet, but any suggestions are appreciated.

I have the exact same car. I found mine out of Florida with no rust or damage.
I paid $600 for mine and it was a steal. Low miles, no rust, doesnt use oil, clean and only has a few old age problems. Back windows dont work, needs shocks. I bought it and drove 200 miles she cruises like a yatch.
Its my daily driver but if another project come salong I would consider parting it for the wole drive train.

Smokin` deal.
I really like driving these big cars and they can usually be had very cheaply making for great project material.

Good score indeed! You should be able to sell it for near $2k and pocket the money.

nice find! Try running codes on it to see if a sensor is going bad. Or the cat, if original, may be plugged enough to cause issues that will warrant a light to come on also. Spray some cleaner on the EGR and that may help, too. Typical EFI stuff, lol. 5.0 I had in an '87 Cougar had the EGR pipe rusted thru which caused the same problem, and my '88 Tbird had both cats plugged enough to cause a stumble. Can't beat the price though. I s'pose you'll be buying a 67-72 F100 and do the body swap, eh?