i put this 390 in my truck and ive put a thousand miles on it and last weekend we went campin and it started makin a wierd noise as i was shuttin it off kinda sounded like it was overheated but the gauge says normal it only does this when i get into the throttle on the road and then get home and shut it off thats when i hear it im not sure if its still gettin broke in or if somethin is goin on with it

 

What kind of noise? Is it knocking around like it's dieseling, is it hissing, etc...

(Also...help us help you by using punctuation in your posts. No offense but one long sentence is very hard to read).

 

Ok the noise sounds like the kind of squeal you have after a motor has overheated, or when it is overheatin. Its around the water pump but everything on the motor is new as far as the coolin system goes. No knockin or hissin just a squeal at idle that keeps goin until i shut it off. The radiator is from the 75 parts truck and is a super cooler. I flushed out the radiator before i put it in and the water pump, thermostat, and woses are all new. The only thing that aint is the radiator. I did put the shroud on it along with a new fan clutch. Sorry for the bad typin im not too good with it.

 

A "squeal"? Could it be a belt?

 

No them are new too and we tightened em up good. I just went out and checked and it aint that. I also got a long pry bar and put my thumb on the end of it and put my ear on my thumb, put it on the alt, ps, and water pump and they all sounded good alt belt was a little loose. So tightened that up and it didnt do a thing for it. Now that i litened to all that im wonderin if its the crank snout rubbin on the timing cover seal?

 

Hey Tonto. While you're at it stick the pry bar in the ground and tell me if there are any buffalo coming!

Just kidding, man.

 

Well they only have been on there a thousand miles or so. Could it get worn that quick? It also is not very loud you can barely hear it whe n your drivin partly cause exhaust is loud. It also goes away when you rev it up over 1000 rpm.

 

Hey it works good for seein if internal parts are good like valves or rockers. Thats what we did when we put a used motor in it before we built the 390.

 

I understand, man. Just mess'n with you.

I still would say you have a belt issue if I understand you right. I'd suggest, as a cheap an easy way to find out, trying that tooth paste idea that Ben suggested. Then if it goes away with the paste, you'll know. If not, then you probably eliminated one thing without spending money on a belt..or taking time to change it.

 

could be a squeeking idler pulley beairng for your a/c pump or sumthing, I had that prob on my '94 Explorer, it would squeek till the engine got warmed up, then quit...........could in no way get to the pulley to oil or WD40 it, so I just put up with it knowing that's what it was...

 

The belt look fine no crack or camelizeation on em.

 

Dont have an idler ar compressor for the ac but have the box.

 

Toothpaste didnt work just tried it. The squeal keeps goin for a little bit after everything has stopped so that why i think its somethin to do with the coolin system.

 

Check your alternator pulley-I had one that got loose-it would work fine until it was loaded at idle, and would squeal and chirp. Turned out the fan was cracking too-on the alternator.
What made me notice the pulley was it was getting rust colored dust around it.
Good luck! I hate odd things like that.

 

You mentioned that it keeps up momentarily after shutting the engine down - do you have a clutch fan? Might be the clutch starting to fail...