Early Heads on late Flathead block

Is this the hole that needs to be plugged?

 

Yep,

Here are some pics of mine.
If you see near the dizzy, the head doesn't even cover it.
It just peaks out on the other side.

 

Not sure why the shop plugged it since I'm runnin' late heads. Guess I'll pull the plug.

 

Plugged the right bank don't remember plugging the left bank, anything possible. I run late gaskets on early engine's, makes them run cooler by slowing down water flow, left bank gasket don't show extra w/port.

 

It won't hurt anything if it's plugged. You can put a small welch/freeze plug in the front of the block above the water pump if you like too.

 

It won't hurt to leave it plugged if I'm running late heads? Only the right bank was plugged. And do I need to plug the ones in the front of the block if I'm running early water pumps? What's the purpose? to slow down water flow, as mentioned above?

 

pull it out we plugged it when we pressure sealed the block and did not take it out.

 

Thanks Mike.

 

It's a thermostat bypass passage. I believe it communicates directly with the top hole of waterpump only, so if you are running this block with early pumps and front gear, the hole can be ignored at both ends.

 

No.
Yes.
T-stat bypass.
No.

What he said.

 

"Ignore", as in, leave them open...or plug them 'cause they're not needed?

 

Haven't looked recently, but from memory that passage just connects the two holes you do not want with early parts, so plug lower end and ignore top...but check me on that! It'll be easy to see and feel if I'm wrong and it connects to water jacket along the way.

 

Another thing to consider : How're you going to clamp the distributor? Many suggest a set screw in the distributor bore of the timing cover but that becomes problematic when you want to adjust timing with engine running. Look at the picture showing the early head on the late block.Trace the pattern of unpainted iron. Duplicate the shape in 3/8" aluminum. Drill and countersink for two 1/4-20 flathead screws-close to top and bottom. Place on block covering the area you made the pattern from. Transfer the two holes to the block then drill & tap for 1/4-20. Temporarily fasten the piece to the block. Insert the distributor. Using the original clamp, determine the location of the 5/16-18 thread for the clamp screw. (the location doesn't have to be within +/- .005 or anything like that.) Remove the new pad (and distributor)and drill and tap the 5/16-18 hole. If you want to plug the water hole go ahead but make sure the top of the plug is flush with the block, otherwise make a gasket and coat both sides with Permatex. Sandwich the gasket between your new aluminum pad and the block and screw it down with the flathead screws. Reinsert the distributor and clamp with original clamp and 5/16 screw.

 

Listen to Dale...MUCH better in several ways than setscrew or VW muffler clamp kludges.
Better, throw all that crap away and use early cam ans 21A distributor!

 

I don't like set screws, I use this approach when I wrote this up I didn't have a Tig but do now so I also do this to the alum covers and works great. See middle of article on hold down
http://www.flatheadv8.org/hei.htm

 

Only block and heads are late...everything else is early.