Question: Late model engine/trans in 1st gen Fbird ???

I've got a 69 Fbird with a 350. Since it was rebuilt (around 2000), it's run hot (above 200 if it idles long). I've done everything I can think of to cool it down (4 core radiator, high output water pump, flattened water pump plate, extra coolant capacity by running through trunk), but not much drop in temp. I'm in Phoenix, so it's always hot/warm.

I'm thinking about putting a late model Fbird/Camaro engine/trans in it. I'd like some recommendations about installation. Do the motor mounts match or do I need adapters? Same with the trans mount? What about drive shaft length? Is the rear-end an issue? I'm not too familiar with the late models, so any help is appreciated. Thanks.

Be sure not to overlook the obvious, coolant mixture, thermostat problems, fan clutch, misreading gauge (sending unit).

I've tried changing the coolant mixture - No obvious change.
I've tried different thermostats/no thermostat - No obvious change.
I have a flex fan on it. No fan clutch.

Is it possible, when the engine was rebuilt, that some of the holes
weren't punched out in the head gaskets?

That or possibly something is clogging the jackets in the same maner. I would be more inclined tho, that since most the "easy to forget " stuff is covered, I'd be checkng out the wiring to and the sending unit itself and verifying if the motor is indeed truely getting that hot. :2cents:

It is definitely getting hot.
It blew a hose yesterday.

I'd try to get the overheating problem solved before I go through the effort of putting a new engine in there :2cents:

Faulty radiator cap :dunno:

here's a link to a forum thats into the hybred you are thinking about.

http://www.ls1tech.com/forums/forumdisplay.php?f=28

an LS-1 and a six speed and 4:10s in a '69 would be ducks delux.
with great drivability and mpgs in the 20s

this is something most people know, especially engine builders, but i thought id throw it out there. you mentioned the possiblity of the head gaskets not allowing coolant through. the older chevy and pontiac engines were not the same. that didnt happen till around the 80's i believe (its goin on 1:00 and im on a study break from physics, cut me some slack :runaround: ) i dont even know if the gaskets from a older sbc would even remotely work on the pontiac engines, but its a thought.

something else to look at, is that alot of places dont always take the freeze plugs out when they do a rebuild. they punch the old ones into the block, and hammer new ones in their place. its shoddy work, but its quicker and faster than doing it the right way, and alot of times it goes unnoticed.

im tryin to think if there are any pontiac engine specific cooling issues but im really fried right now. only thing i can really think of is that youre running pig rich, or way lean, causing really high combustion temps, which would heat the engine up.

edit: you never mentioned the thermostat... have you tried changing that? maybe putting a 180* or perhaps in a drastic measure a 160* unit in the housing? you can check a thermostat by putting it in a pot of boiling water, with a thermometer. and boiling the thermostat. it should open at a certain degree. im not 100% sure about the first gen pontiacs. i would say somewhere around 200*-215*. if it dosnt open, then thats your problem. You can also test this, by taking the thermostat out, and running without it. I do NOT reccomend you do this as a fix, but it could help diagnose the problem, and it really only costs you a housing gasket. if you remove the thermostat, and can drive around without the car overheating, then its the thermostat that is your problem. and you should either put in a stock replacment, or a lower temp one to reflect the area you live in.