blocking heat crossover

I have a set of '70 non stage 455 heads that I want to block the heat crossover on. On these heads they have two threaded holes on each side which I thought I could thread plugs into but they seem to have an odd thread size. Standard course as well as fine thread will not fit. Does anyone have any experience with these?

The intake gaskets have a rectangular hole here. If I can't find plugs to fit the heads could I just cut some gasket material to fit the holes in the gaskets or would this burn out eventually?

My machinist was supposed to plug these from the inside when he did the heads and I didn't notice he didn't 'til I went to put the intake on. :af:

 

when I plugged mine I used 3/4" freeze plugs, and a little persuation w\a hammer :beer

 

hey i did this on my '70 non-stage 1 heads and had a bit of trouble with the 3/4 plugs. i cant remember what size i used but i used mm closest to 3/4 and fit perfectly. so go n get the mm ones and u should be good! :Smarty: :TU:

 

18 mm cup plugs work fine on 95% of all 1970 heads.

The other 5% have slightly larger holes due to rust or whatever....

Measure id of hole first, because if plug is too small and does not fit tight it will fall into exhaust port...........

 

Thanks for the replies guys. Are the mm and 18 mm cup plugs you guys are talking about threaded plugs or are they simular to freeze plugs? Also, where do you guys get them? I've been to half a dozen hardware and auto parts stores and have yet to come up with anything that will work.

Its ridiculous how much time I'm wasting on this when I could be using my time for returning wrong parts and re-doing or finishing work I paid someone else to do

Thanks again

 

Press fit plugs

:tu:

 

I got mine at a local parts store, Autozone... most stores should carry them. Ask for 18mm (miller meter) freeze plugs. Most people like to use brass plugs but I dont think it really matters.
~Vin

 

Thanks again,

So far I've been to 2 Autozones, Advance & NAPA. There's another NAPA with a machine shop that wasn't open on the weekend. They "should" have 'em.

 

freeze plugs..

 

I had to sand the edges of the freeze plugs to get them in.Then 16 oz hammer did the job. :laugh:

 

Went to the NAPA with the machine shop today and they didn't have em either. Apparently this is only a problem here in the south.