Question: How many threads are in the plug holes of the 5.4 heads that are blowing out plugs? A guy is trying to sell me a set of PI heads that each have 6 threads per plug (I counted). For these and a intake manifold, he wants $200? Is he trying to rip me off?

 

I think the early 5.4 liter heads had 3-4 threads.

 

If they are low mile heads, that is a decent price for PI heads plus the intake. The '03 heads I got for my '98 had 8-9 threads. As was mentioned, the early heads had 4 threads. I've never heard of 6, but that is better than 4.

Check the surface of the heads, if they are scratched, you'll need to have them machined for the MLS gaskets to seal properly. Something to factor into the total cost.

 

Ted'98

How much, if any, difference have you noticed with the PI heads? My replacement engine is already built, and I'm wondering if it's worth the trouble to rebuild them. If I do use them, I'll have a valve job done and have them gone over well.

 

A very noticeable difference. It isn't like bolting on a supercharger or dropping in a 5.4, but it was a nice improvement.

 

Forgot to say that they're going on a 5.4 that's sitting in my garage. I was just wondering if it was worth the effort to change them.