Hi,
I'm not as familiar with TIV cooling as I am with type 1 cooling. I'm still trying to sort out what I have here, and what the PO ( or DPO, we'll see) has done. The heater boxes have been deleted due to the addition of a header (I'll post pics later after I have it on jackstands to see if you guys can identify it). My concern is that I am losing cooling capacity from this location. I guess they could also be outlets for the fan air before the thermostat opens? My main question is whether or not I need to plug/cap them. Thanks!

--Jaybird
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That air is "allotted" for cabin heating. Without the boxes, the "leak" is larger than if you had the boxes installed and turned on since there is no plumbing to present resistance to the blower at these openings. Plug the hole if you don't intend to install heater boxes.

they should be plugged when running headers.

they used to have a small aluminum flap on them that people usually just epoxy down.
Andy

Quick, easy and cheep? Little rubber ball from the local toy store, shove it a little over half way in. Works.

Hmm... I guess I should do that to mine too. No heater boxes when I got the car, but no headers either. The boxes were just falling off of the stock exhaust. I didn't know that's what that duct was for.
Mark D.

If you drive your car in hot weather, it's more important to close those holes than in moderate/cool climates.

Brings up a fundamental difference between air and water cooled cars. In a water cooled car, running the heater helps cool the engine, while in air-cooled, it diverts potential cooling air, so actually heats up the engine.

Are you serious Clarke

I may be CSOB... but that one goes way beyond what I would do.

Stick a sock in it.

Thanks all.... that was my guess. I did the same thing on my '70 Ghia by putting freeze plugs in the heater hose outlets. In these 100 deg south Texas days, I need all the cooling air I can get. --Jaybird

could you use speed-tape on those? YOu know that aluminum tape stuff? I have the same holes wide open on my car too, and Houston is of course one of those wonderfully cool places

I believe that when using heat exchangers, this air is not wasted. It helps cool the exhaust pipes. That warmed air will either go into the passenger compartment or out the top of the flapper boxes.

You got a point there as the bell cover looking thing on the flapper boxes does pass air always.

You will get more benefit from a good tune up. and a clean oil cooler.

Let your car idle spray some Purple power in the fan and then spray a water hose in the fan while revving the engine. Black shit will come out everywhere. It also shows you where air is escaping from crappy fitting cooling tin.

Plugging the holes in the tin where the J-tubes come up through is REALLY important.

Paul sticking a sock in it? maybe that's what "the old ball and chain needs"