I've grown tired of battling exhaust leaks with my shorty headers and have decided to put the original manifolds back on my 1994 F-150 with the 5.8L.
My question - do these factory manifolds require a gasket?? It was a number of years back that I put the headers on but I seem to recall there was no gasket when I took the manifolds off (they were the original set up).

 

Fel-Pro #1415

 

You're saying they did come with gaskets?

 

I'm saying that is the gasket part number. Ford put them together at the factory without gaskets. Trying to do so with a manifold that has been heat cycled is a really bad idea. It will never seal up properly. Spend a couple of $$ and buy the gaskets.

 

Got it and I'll do that. Thanks.

 

And then put them on the headers before you buy manifolds. Unless you bought crappy headers, they should be fine.

 

take your headers off, hold a straight edge to the flange, see if theres any high or low spots, if there are any run the entire flange on a belt sander flat and even. i had LT headers on my truck for 10k miles and didnt have one leak

 

I didn't have to change to the manifolds - turned out that my exhaust leak was from the EGR tube and it was hiding under the cloth sleeve!! I'm really glad because it is virtually impossible to get at the very rear bolt on the passenger side of these headers (cheap *** Summiit shorties that I would never buy again). After some doing to get the old rusted EGR tube off and $75 for a new one from Ford .... we are back to normal.

 

Gaskets suck. I just removed them from a reman engine with only a few Kmi on them. They had already rusted out. I put the used manifolds back on without gaskets, and they're totally sealed now. No machining. Read these captions:

 

Crappy gaskets suck. Good ones do the job just fine.

 

Then I've never seen a good one, and NO gasket does the job for less $$ & effort. I don't have them on my exhaust, I removed them from that truck, I didn't put any on Frank's '75 Bronco, and I've never put them on any Ford engine I've installed, including my CV.