Hey guys My 77 with a 400 has started burning oil on start up and when I get on it good. The motor runs real strong but I dont like it burning oil. If I start it it puffs out a big puff of smoke and if I let it warm up and then shut it off and then restart it again it dosent smoke. and the lower the oil level gets the more it burns. Is this somthing to do with the valves leaking. If so how much would it cost for me to have the heads rebuilt. If not what could it be.

 

If it blows smoke when you first start it then stops...it's valve seals. All engines use oil and my experience is the harder they're run the more oil they use. Heads are anywhere from $250 on up depending on who you know, where you're at and what you want. Hope this helps

 

My 400 was doing the same thing so I bought another 400 to rebuild and then drop in when it was ready. I was sure I had worn cylinders and rings but when I tore down the motor the cylinders were good. The heads are another story, the valve guides are very worn. I had installed new valve stem seals before I decided on a new motor and this helped some. I probably could have just done the heads and got more life out of the motor.

Head work can be expensive depending what needs done. The heads on my replacement motor were in such bad shape I bought another set to save money. Although the heads I bought were "just rebuilt and ready to run" I had all of the guides but 2 knerled and the other 2 needed bronze liners. I should have put liners in all of them but I didn't want to fork over the 18 bucks a valve to have them done. I got off paying 150.00 dollars to have them done and 150 for the "just rebuilt" heads.

 

I havent checked out how much it would cost to rebuild the heads around here but I went to napa and I can get rebuilt heads with valves, spings, and all of the other stuff so I can just bolt them on for $138.00 a piece. With $10 shipping. Does that sound good?

 

not bad if you are planning on selling it before this happens.
http://myweb.cableone.net/jmanley/mustang_destruct.htm
it happened to me once, 3 days into owning the car. it had just had a "valve job"! i didn't know it is a standard problem that needs to be addressed, i thought it was a fluke. i even had a set of 4V's set up with triple springs and the guy didn't clue me in. the spring in the pic's is by no means anything radical that would've shot the head off the valve stem. use 1 piece valves! they are way less expensive than not using them!

 

What do you mean by that. I plan on keeping the truck for a long time.