On the last main cap is there supposed to be a freeze plug in the last available hole on the block?

 

One of the chevy magazines I have says dont forget to put a plug in that hole but my machinist says that there is a pressed ball in that hole. Do I need to worry about this or is that pressed ball what is supposed to be in there and no plug

 

there is supposed to be a welch plug there

i've never seen a pressed "ball" used there before ???

i just pop the plug out before cleaning block and tap that hole very carefully to correct depth and install pipe plug
you have to light check this depth visually
you can go too far down and block or partially block off the other passage

or go back and use welch plug like it was from factory

either way..a plug of some sort has to be there

 

So the welch plug stops flush with the block and is not supposed to block the passage that runs perpendicular from the main journal to the oil filter by-pass about 1/2 an inch down that hole.

 

there is a small lip/register machined in that hole that locates the proper OEM depth for the welch plug


you have to use a very good quality NPT tap
because when it hits this register , the tap has 2 make approx 2 more threads to be able to put a pipe plug

if the pipe plug route is the way you want to go

i "Light" check all passages

and Varsol flow test all passages

caught a brand-new Dart Big M block not completely drilled thru in the number 3 main by flowtesting all oil passages

 

i always purchase the Pioneer Brass-freeze plug kit for the SBC 400 block..even for 350 cid

that way you get a couple of extra Brass freeze plugs

overtime , it amounts to quite a lot

 

The LTx cars have a ball bearing that is made for that hole but it's still the same place and everything as the plugs on old SBCs.