Chevy Nova Forum banner

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
See less See more
1 - 1 of 6 Posts
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.
On that TBI motor, those heads do not have a coolant restrictor, there is no coolant passage back there if I recall due to the TBI not needing fuel to be preheated for cold start/run conditions (this was handled by the temp control switch in the manifold/block telling the archaic "computer" to fatten things up). If there's a space in the new gasket for it, replace the plate. If there isn't, leave it out. Victor Reintz (SP) typically makes two different gasket kits for that TBI setup (different bolt pattern... still damn near the same) and I for the life of me cannot find out why.

Here's the VR set with the blockoffs installed in the gasket itself:
Product Rectangle Font Automotive exterior Auto part

Then here's a Fel Pro without them (in the small baggie that comes with the kit...):
Azure Rectangle Font Parallel Electric blue

Personally, if the gasket kit comes with the plates already installed, you're far better off. I would however add the RTV around the port on the head (not on the gasket) then apply the gasket and manifold.
See less See more
1 - 1 of 6 Posts