Cast Iron Intake Manifold ports welded shut?!

[bobs73challenger]

Hi everyone,

I've finally started my intake manifold replacement.  Replacing a cast iron with an Edelbrock Performer RPM.  Decided to do valve covers at the same time, because they leak quite a bit.

When I took off the cast iron intake, it looks like some ports were welded shut.  I've attached pictures.  It's the same ports on both sides.  It also looks like some kind of plate was installed to the bottom of the intake.  It MIGHT be factory, but it doesn't look like my new Edelbrock.

Motor is a 360.  Haven't been able to figure out what year, but certainly not original to the car. 

I'm wondering what the heck would possess someone to weld ports shuts on an intake manifold?  I guess it doesn't matter much -- I'm installing a new intake manifold anyway, I'm just really curious about this.

Also -- just want to ask a couple of general questions about the manifold replacement:

1) Should I re-use the intake manifold bolts?  I know I can, and these look pretty good, but if its worth it just to pony up a few extra bucks for new bolts, than so be it.
2) Same question, but for valve cover bolts.
3) General consensus is that the cork front and rear gaskets that come part of an intake manifold gasket set is that theyre junk and just use (black) RTV, right?

 Any feedback/suggestions you guys can offer is (as always!) appreciated.  I'd like to do this job the right way, the first time.  And figure out why closing intake manifold ports is a good idea 

Thank you!

Bob

EDIT: edited post to include information about motor.

[Strawdawg]

Closing the exhaust crossover passages keeps the carb from getting too hot and boiling the fuel in the bowls. On the other hand it can slow down the engine warm up on cold days. Normally we plug these in the name of performance using plugs that come with the intake gasket set

Steve

[Jesus H Chrysler]

Most of the small block intakes I've pulled over the years have the center crossover port blocked just like that.  It's not welding, it's carbon, burnt oil and sludge etc.  built up and functions like a plug.  It's a real pain to get out, but the only reason you'd want it out is for heated carburetor plenum, which is bad for performance,  I usually left them plugged.  The rear "plugs" are just the outline of the intake gasket made with coolant sludge.  They are not open crossovers, they are the mirror image of the coolant crossover at the front of the engine.  They are supposed to be blocked off on that intake.  If you cleaned off that part, you'd see it's machined metal.

1 and 2, yes you can reuse the bolts if they're in good condition.  If not, feel free to replace.  They aren't "high stress" parts like rod or main bolts.
3, I use the cork, but I use gasket adhesive that makes them tacky, and RTV the corners where they meet the metal intake gaskets.  Remember to remove or pound down the roll pins at the front and rear of the block.  Edelbrock intakes don't have the relief holes drilled in them like the factory ones do, so they'll hold your intake up too high and you'll never get it bolted.  Worse, if you keep torquing the intake bolts, you may crack or break it.

[bobs73challenger]

Well, thats a complete facepalm of a moment for me. 

I've read a lot about the virtues of blocking off the exhaust crossover passages. 

I knew that the new gaskets I bought blocked off the passages on my new intake, but never considered that the passages wouldve been blocked from the intake itself. 

Jesus H Chrysler, you're probably right about the sludge blocking the other port. 

When I'm playing with it later, I'll have to check out the roll pins.  Thanks for that piece of advice, I never would've even looked for it. 

You guys are the best!

[jimynick]

When you're getting ready to set the new intake on, be sure you use brake cleaner on all mating surfaces before you RTV them, to ensure a good bond and I usually skin wipe them with the RTV over the whole cork surface as well. You can wipe of any squeeze out with a rag. 

[cudabob496]

I'd also set new intake on heads, without gaskets, and bolt holes lined up, and check gaps, no make sure they are within spec, and intake and head
surfaces are truly flat. Might have a high point or flaw in the way.  Not mated well can have results like intake valves sucking oil from crank case.

Also, line up holes, and set the gaskets on the heads, and make sure they are not covering any portion of the intake ports.  Set set gaskets on the intakes as well.
I use a die grinder to open up the gaskets a little sometimes.

[bobs73challenger]

Thanks so far everyone. 

So far, so good.  Cast iron intake is off (what a heavy little fella), RTV is scraped off front and rear.  The heads are  mess so I've got to do some cleanup before I'm ready to start putting on the new stuff. 

Anyway -- this is a bit of an afterthought, but do I want to put in a valley pan?  There wasn't one there before, but I see Summit sells one.  Just trying to figure out if it's something I should be doing while I'm this far.

Thanks again!

[Jesus H Chrysler]

Performer RPM doesn't need a valley pan.  It's for big blocks, or really exotic small block intakes that don't seal the cam valley.

[jimynick]

I see you're into cleaning mode- remember; cleanliness is next to Godliness and make sure you isolate the lifter valley and plug all other openings before the kaka starts to get into your engine. You won't be happy if it does.