My truck has been sitting at the mechanics for months now, and will for several more. I originally took it to him for an exhaust manifold gasket replacement, but after getting into it he found two hairline cracks in the head, and a pinhole in #5 cylinder, so I've ordered a remanufactured engine that won't arrive until November.

When I talked to him a few days ago he said the intake/exhaust manifold wasn't coming apart no matter how much effort/heat/lubrication was applied. My question is should I get new intake/exhaust manifold since the old one could be warped from expansion/contraction. I don't have it here to look at, so are there other parts connected to the intake/exhaust manifold I should get also? I know there will be gaskets and bolts, but are there emission parts? Who would be a good supplier for the manifold(s)? Is this a Rock Auto/ online supplier, or my local auto parts store purchase?

I want this process done right, and I don't feel comfortable putting the old manifold back on the remanufactured engine. Applicable comments..

 

Wut?

I don't know what year you're working with, but on the EFI 4.9's, the Intake and Exhaust Manifolds don't connect to each other, at all, in anyway, except where they share fasteners on the head. If they've been removed from the head, there is *literally* nothing to hold them to each other.

Unless there's some setup out there that I just haven't seen, but I've seen a lot of these things over the years.

If he's talking about separating the upper Plenum, from the lower plenum on the intake manifold, that might be stuck together, but I have a hard time seeing a circumstance where it's "impossible" to separate the two.

 

Maybe I misunderstood, thinking he pulled both pieces out to show me, but the manifold he pulled out of my truck and showed me was connected by at least one bolt which wasn't going to be removed. Like I said I don't have the truck here in front of me to look at. My understanding is that both the intake and exhaust are connected on a 1991 F150 2wd and they share a gasket. None the less the question still remains about the old manifold possibly being a bad idea to put on a remanufactured motor.

 

If the old manifolds are not warped/broken, there is no good reason to replace them. New ones won't "perform" better or anything.

 

I'm not sure if they aren't warped. Trying to figure out why there was all of the engine sealant residue might go a long way to explaining what the original engine had been through. The previous owner won't tell.. But none the less, I'll talk to the mechanic eventually. I really didn't want to bother him because his old dog was killed by a bear recently.

 

If you're scraping the block / head, put a break bar on the last bolts, break them and pull whatever you need off the block...