Hey all I found an aluminum 2bbl intake for sale near me for $150 bucks. The part # is 4104577, I did some research and couldn't quite figure out if this is the good one. The better one is supposedly a 1 piece casting? Just wondering if I should pick it up or if that's too spendy. Im new to these parts and motors so just curious. I can't upload the pictures of it because the files are too big (I even tried cropping them) It looks to be clean and in good shape.. any input would be great thanks!

Ok I did some more research I think im gonna pass on that one anyways. Im pretty sure it's the two piece one that's welded together and I don't want to risk dealing with leaks.

Nice thing about the two piece slant six manifold is that they are really light.
Taking weight off a slant six motor is a good thing, especially weight that sets higher than the top of the tires.

Concerning leaks, there are several low cost ways to treat the seams on those intakes to eliminate any possibility of a leak
some of those are:
1) paint the exterior seams of the intake with an epoxy based paint
2) paint the seams of the intake with a sealing paint like POR-15 or Glyptal
3) coat the seams with Loctite 290, one could probably use a vacuum cleaner to apply negative pressure inside the manifold while coating the seams to suck the loctite into any voids, kind of a shade tree impregnation process

using any of the methods listed one would need to throughly clean the surfaces of the manifold to promote the best possible adhesion.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

If this is the one on Portland Craigslist, yes it's a two piece. I wouldn't be concerned about it leaking. I'd go over the seams as suggested by Dad Truck. It's a bit spendy but I'd try negotiating it closer to $100 if possible.

yea, tell them of the leak potential and say that you will take it off their hands...

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Haha yep that's the one! It's on offerup too, it's a little bit of a dive down there so I'll keep looking for now!

Yeah! That seems like it would definitely eliminate any leak potential if I get it that's what i'll do!

Really, you don't need to fret about the weld bead. There's a damn-near-zero chance of getting one of these intakes with a porous weld bead, because the overwhelming majority of those went for scrap so many years ago that whatever they were melted down and made into has probably also been scrapped. There was a factory service campaign/recall early in the production life of these intakes; that identified most of the defective ones and removed them from service. The few remaining would have been identified as the cause of poor running and replaced outside the service campaign.

Of greater concern is whether the manifold is cracked in the plenum floor. That area is subject to the most brutal thermal cycling because of the exhaust hot spot and EGR, and this low-mass casting is more prone to cracking as a result than the heavier iron and 1-piece aluminum intakes.

That said, the weld bead on the 2-piece intake is ugly, and that's a good enough reason to want to fill it in and tidy it up.

No need for a vacuum chamber. Thoroughly clean the intake—have it media blasted (glass beads, fine. Walnut shells, fine. Brake lathe turnings, fine. Sand or other large aggressive media, NOT OK). That will give you a good chance to check for floor cracks, warpage of the gasket surfaces, etc.

If it passes those inspections (and after you've had the gasket surfaces planed flat, as necessary), put the intake in a kitchen oven set to around 275°F and leave it there for 30 minutes or so. Meanwhile, get your tube of this stuff (specifically) ready in your Tube Grip tool (whaddya mean, don't have one?!) and have some clean, new wooden tongue depressors ready, and some paper towels.

Just before you remove the intake from the oven, close windows and turn off A/C and eliminate other sources of wind/draft where you're working. Then open the tube of RTV and cut the nozzle to the right size, etc. Then pull the manifold out of the oven and put it rightside-up on a work surface (like, on top of the stove, maybe on a piece of cardboard). Quickly and neatly apply a continuous bead of the RTV to the weld bead, then quickly smooth it firmly into the weld bead—I carefully used my thumb and did fine, but if you're worried about getting burnt, work with a tongue depressor. Then take the intake outside and let it cool. As the air trapped in the weld bead bubbles cools down, it'll pull the RTV down into the bubbles. End result looked good and worked fine for me.

Other methods work well, too, like high-solids/epoxy paint.

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