heater core box holes... stock or modified?

[jks67ss396]

Hi guys

I am replacing my heater core and have always wondered about the larger hole in the heater core box. The holes are where the heater hoses from to/from. Im starting to see pics of where those holes appear to be oval rather than round. Are they oval/enlarged/too big for the hoses right from the factory? My trucks previous owner (PhD in hack jobs... got most worked out covered the holes with "mylar tape" like he was trying to hide their oval-ness

Can you guys confirm the oval shape?

thanks!

[mmsidaho]

The box on the engine side of my firewall has oval shaped holes (1972 C10 no-AC). I'm planning on using silicon to seal everything up when I put mine back together. The gasket kit I got from Brother's had some foam pieces that slide over the two tubes of the heater core that should work to serve as a backing for the silicon.

I already had to do some repair/patch work on the areas where the screws go through to hold the heater core in place.

[jks67ss396]

so i take it the oval holes are stock? are they supposed to be filled in with the gasket or are you just doing that to seal up the box better?

[mmsidaho]

I'm assuming the oval holes are stock as they are neat, clean and well defined. I'm going to use silicone along with the foam gasket just to make sure everything is sealed up good. PO had done it that way as well.

[midniteblues]

I didnt like the look of the oval holes and large gaps when i did mine.

i have a small bin full of valve cover breather grommets.\
low an behold the ones with the bigger holes(think 7/8" or 1") fit in the oval holes all most perfectly i rounded mine out just a tad so the heater core tubes could slide through gromment easyly .

once again sorry i got no pic's of it