I need to know how much this would be, ball park estimate. I just need new valve, springs, and rocker arms.

My 3.9L jumped time and screwed up the valves. I took the valve covers off and had loose rocker arms. After removing the intake I found a few bent pushrods too.

The timing issue was the cam gear, it was almost bald on one side, I have since installed a timing kit.

 

What is a "timing kit"?
I don't know about rebuilding a head but I have purchased a rebuilt head from this guy and it works fine started right up. http://www.ramscyl.com/index.htm
The best part is no core fee for 30 days, you just put the used one in the same box the rebuilt came in and call or take it to UPS its already paid for.
Other than that if you are wanting to do it your self I like Hughes Engines for parts they helped me a lot when I did the plenum kit and Timing chain/tensioner TSB.

 

bomb00, alot of 3.9 motor parts are used in the 5.2 magnum... which i have a set of rockers and push rods, pm me if interested.
94dak, a timing set will include both gears and the chain.

 

I will check that out

 

Yup I know, its like they cut off a couple cylinders.

 

Don't know what year your truck is, and it will make a difference, but looking at rockauto, you can get a complete 3.9 head for a 93 for $200.00 exchange. Core charge was $75.00. Machine shop charges differ greatly based on the area you live in..... For me, its almost always better to send out or buy remanufactured rather then using local shops. But then again, I am in a high labor rate area.

 

It's a 94, I didn't realize the heads differ in the first gen 3.9L. I live in KY so probably a low end labor rate.

 

I think the magnum series are all the same, but 87-91 are different. FWIW If you go with one such as the rockauto one, you have a warranty and will not get hit with surprises such as, after clean up they find a crack, or you need guides, etc.
I am about 30 miles west of DC. I have a set of chevy LT1 alum. heads. Took them to a local machine shop. He cleaned, milled, replaced guides, seals, and seats. pressure tested as well. But reused springs, retainers, valves, etc. It cost me a little over $1200.00. Any more, unless it is something custom, I go remanufacture , rather then local. And the warranty is almost always better.

 

Well, there's the LA 3.9, which was from 1987 to 1991 or 1992, and the Magnum, which is from the next year to the time they quit using the 3.9 .

The heads CAN be swapped, but it's not a unbolt/rebolt type job, so it's better to not swap them.

Being a 1994, yours is a Magnum, even if you DID swap to the LA heads, they're a step back in horsepower it turns out ...

RwP

 

If you use that linked site the you can get the head fully built. They are tanked and repaired ready for use. I bought a built head bolted it in and started it right up. I think for the 94 Magnum its somewhere around $600 for the pair of them. The price of the built head includes the return shipping for the core.