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OEM GM 350 Intake Coolant Block Off Plates

496 Views 5 Replies 3 Participants Last post by  railroaderman
Not Nova, my 94 GMC Truck. OEM everything on the truck.

Replacing Head and Intake gaskets due to coolant leak. The original intake gaskets had a Block-Off plate on each of the rear coolant ports. Each plate has small hole. New intake gasket is solid with no openings for same locations.

Do I :
Put the plates back in and solid gasket over them?
Put the plates back in and add small hole to gasket?
Leave the plates out and open up the gasket?

What the basis of the rear coolant ports being blocked off. The intake does have a rear connection to heater core, is that the reason? But, driver's side was also block off. ??

Picture of plate below.

Gas Font Rectangle Metal Communication Device
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Wong gasket? If I remember correctly on the pass rear has that quick connector fitting…that always like to leak. if you want heat, need some coolant flow.
Why the general slowed the coolant flow down with those restrictor plates, I don’t know. Maybe some else can chime in on that.
Drill same size hole in the set you have now or if it were me, get gskt set with proper metal insert, for better crush, and of course back it up with some sealant, especially if heads and intake have a bit of pitting. I’ve replaced many of those gaskets and quick connectors, but never really thought why they put restrictors in… it works, so never questioned it… plus i was flat rate back in the day…..just getr done was the way.

edit: could be a bring it up to op temp quicker “emissions” and rely on T stat to maintain, along with higher press cap…

your doing good if those were actually orig.👍
I won’t get into the Dexcool crap….
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