Question on 1990 ford Tbird

Hey all just sold the 79 TA for way more than we paid for it :D And bought a beater 1990 TBird with a 3.8.
The body is in pretty good shape and all the car is good except for the engine. Overheats in about 20 min of driving, I am thinking the head gasket is shot as once it overheats you got the sweet smell. The radiator has alot of cotton covering it from the cottonwoods. Would that cause the high temps? Or is it something else? The fan runs, The water pump seems to be working, thermostat seems to be open to allow the flow, not sure if its working properly though.
Haven't checked to see if there is water in the oil or vice versa yet as I am working long shifts and haven't had a day off since we got the car.
Does anyone have an idea where to start with this cooling issue? Or are the 90 tbird engines aluminum? so I should start with junking this one?

Also what engine would fit as a replacement for this one? and can anyone tell me a little more about the 90 t bird? like tranny and rearend? the tranny is an auto

The Thunderbird trans is electronic, probably an A4LD overdrive. The same trans as in the Ranger/Explorer/Aerostar.

The 3.8's are SLOW, unless you have the Eaton on top.

The diff is a thing of beauty. It's an 8.8 center with independent suspension like a Jag. Better than a Jag, really, because the brakes are outboard and parst are cheaper. It comes out as one large piece with subframe and all.

I was going to use one in my f100, but I decided against it because I'm still using it as a truck and I was worried about it's loading limit.

Well at least the rear end can be useable when we decide to scrap it as this was only going to be a winter car.
Thanks Madgrinder

the 3.8, at least the FWD version is famous for head gasket issues.

clean up the tree debris.

pull the plugs and look at them - if one cylinder is getting antifreeze in it it will be CLEAN compared to the others. If you have a sniffer for emmissions or possibly freon, run the car with the rad cap off and sniff the antifreeze for hydrocarbons. You could also pressure test the cooling system. Perhaps AutoZone has a tester to loan out for free?

as for a winter ride, these cars suck in the snow. if it has a posi rear you'll do OK.

the 302 was available in them...not sure what all is needed to swap things over.

Thanks guys, it is the rea474r wheel drive and that is what I am used to driving in the winters up here. I will test the cooling system on friday when I have a day off, I am also going to clean the radiator and probably flush it also at that time. Then start looking at the plugs to see what we have there.
Thanks for the tips guys, any others would be appreciated as this is the 1st ford I am actually going to do the work myself on, I am a chevy man