Ok to start im only 17 years old and I have a tight budget so im doing kind of a budget build I have a 79 f-250 with a 400 and I want to add a 600 cfm holley a weiland intake double roller timing I want to take the heads off get them rebuilt and milled then add headers and straight pipes I just wanted a easy build that I could do on my own will that be a more then noticeable difference on my all stock 400 and what kind of numbers am I looking at with doing that....thanks

 

How many miles are on the motor?
Is there anything wrong with the heads?

A 600 CFM Holley, and Weiand #8010 Intake, along with a double roller timing chain set 'straight-up' is a good start, and along with headers, will give you good power improvement for a reasonable expense.

If it is a high mileage motor, and the heads are OK, I think that you should leave them alone.
If it is a high mileage motor and the heads need work, chances are that there is wear in the rest of the motor.
You should consider a complete rebuild with new High Compression pistons. Of course that will be more expensive, but it will be more effective than milling the heads.

 

The motor has been rebuilt and doesnt have very many miles on it

 

I am not a fan of milling heads, it reduces the thickness of the deck, and increases the chance of warping if the motor ever overheats. Milling 0.020" off the heads will increase the CR by about 0.25 points. You should talk to a local machine shop about how much they are willing to take off. I am sure that you will not get any guarantee about the life of the heads if they take a lot off.

 

Well is there anything else I could do to the stock heads to help them out a bit??? Or any other things I could do to make cheap horsepower?

 

With an F250 you want to increase the Torque at low RPM more than increasing the Horsepower. Increasing the compression ratio is the best way to increase the Torque. Other things are:
a higher lift cam (Comp Cams 255DEH)
porting the exhaust ports and clean up the bowl on the intake ports
roller rockers (Scorpion)
If you take the heads off use Fel-Pro Performance Head Gaskets, not the gaskets that come in a kit.

Who did the rebuild of your motor? Was it a local shop or did you buy it from an commercial rebuilder or dealer?

 

Leave the heads alone and swap in a cam that takes advantage of the low compression ratio. Like a Comp 268H. Summit's # 5200 also works great in a stock 400. As for Felpro Performance head gaskets, stay away from the Print-o-seal's. They're not good gaskets. I've had and read of many others that had failures with em.

 

I always use the Felpro blue head gaskets - with proper deck prep they seal prefectly well. If the engine is stock 79, the best thing you could do would be to swap on a set of heads from 1971. But that is not a budget item. Leave 'em alone and run a shorter cam to increase cylinder pressure. Dial it in - along with the balancer - to make sure it's set up in the motor correctly. Do not go by the timing marks alone.