[brigitte2378sack]

Do you have the engine serial number? more

[bitdragon]

It sounds like restricted would increase the pressure of the water flow vs open. But open just sounds like the right thing to d - let as much water as possible flow through.

[astrid01]

Blank - I would call it "blocked" for now flow - and off my option list
Restricted - 2 of 4 holes open
Open - 4 of 4 holes open

[Elanthius]

And do you have any risers? more

[firstgrip]

It used to be traditional for hot rodders to insert shim steel blockoff plates in the crossover passages as soon as the weather got warm. The idea was that the plates would rust out and restore carburetor heat before the weather got cold again. [links]

[Artlav]

Thanks. We have received your request and will respond promptly.

[valam]

One of the replies I got was: “those were included when GM used a piece of stainless steel tubing inside the intake manifold to supply heat to the choke. If your engine does not have that kind of choke you don't need the block offs”. more

[poet_imp]

As TheBlacksmith suggested, get some EGR block-off plates for your 28-year-old engine. [links]

[forsaken1111]

(Question) When should these inserts be used? more

[Wayne33botha]

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

[bravenec]

It's the "maybe" part that's a problem because manifolds and risers don't have an expiration date or a warning light to tell you when they're failing. And when they fail, they can destroy the engine. Damage to gas engines is far more common, so that's the focus of this article.

[Remizor]

Take a large flat-head screwdriver and dig around for corroded metal that's easily removed. If you hit solid metal right away, it's probably OK, but if large chunks flake off, replace it. There should be no evidence of rust in the gas-only chamber on the side that connects to the manifold (expect to see black carbon). If there's rust, water is probably leaking in through a hole in the water jacket at the upper loop of the riser. [links]

[lowifi]

Rust on the outside of a manifold or riser often means damaging rust on the inside, too. here

[jadedinformatio]

Shouldn't there be only one gasket?

[namkeeno]

I put the question on here and the 2859 Forum, and somebody mumbled "service manual", so I opened mine up. [links]

[Nerd]

Shouldn't there be only one gasket? here