Confused on a new part from LMC (pics)

[KMK454]

I'm trying to put my truck to 100% stock so I picked up some 78 305 manifolds from LMC truck. I figured putting these on and just having an exhaust shop fabricate the rest of the piping and rebuild the carb would smooth out the motor and stop it from running so rich.

Well, here are the parts, and the left side manifolds are confusing me - what's up with the bolt? I can't find anything in Chilton's or in the engine bay that would bolt up to this part... anyone know?

Here is the pic:


Note the bolt on the bottom right... I'm thinking at this point of just plugging it up good if I can't see anything it's supposed to bolt to.

[Pyrotechnic]

Maybe an O2 sensor bung for a TBI 305 ?

[mercman1951]

Originally Posted by Pyrotechnic

Maybe an O2 sensor bung for a TBI 305 ?

Yep..."UNIVERSAL APPLICATION" comes to mind...

Plug it and forget about it. If you're going for a concours resto, these won't fit the bill...

[Rc 415]

Originally Posted by Pyrotechnic

Maybe an O2 sensor bung for a TBI 305 ?

I agree

[KMK454]

Originally Posted by mercman1951

Yep..."UNIVERSAL APPLICATION" comes to mind...

Plug it and forget about it. If you're going for a concours resto, these won't fit the bill...

That's what I was worried about... at first I thought maybe something was hung off of it internally. I'll call LMC and see if they have one without the holes, otherwise I'll probably plug it and use these for now until it gets the full frame-off years down the line

[chev74]

those can be hard to plug sometimes. my buddy plugged his headers that came with an O2 sensor hole, but it kept backing out. We even bought a brass plug to do it and it wouldnt stay. We ended up taking them off and completely filling in the hole with a welder... no more leak to say the least...

[87rado]

If you want to plug something on the exhaust, it's best to use like materials if possible. Cast plug in iron. Steel in steel and stainless in stainless. Like metals have closer to the same expansion and contraction rates and would heat and cool closer together.
The brass plug was probably cooling much quicker and loosening up that way. The also have high temp sealants that can be used like a threadlocker. If you use the good stuff, its as good as a weld cause you won't be getting it back out again.

[gchemist]

The flux capasitor goes there!!! You gain 100 HP if you use it.

[MylilBowTie]

You could also install an Oxygen sensor and tune your carb pretty good.

[Pyrotechnic]

Did the electronic Quadrajets have an O2 sensor as well?

The thing that gets me is that if it was a universal application, then they should at least include a plug for those with regular carburetors. I'm thinking that maybe someone just picked up the wrong manifolds by mistake. I would at least call up and question them.

[87rado]

Could it be for a butterfly valve?

[79SHORTWIDE]

try your local auto parts stores..NAPA, O'reily etc. They probably carry the DORMAN brand of manifolds. You might find one that is more to your liking. And the DORMAN catalog has pics so you can be sure. Good luck.

[DURRTY]

The salvage yard has the part too. Probally from the same truck of the same year. Sand blast and paint/coat them (what ever you like) and youll have the OEM part your looking for.