My 71 350/270 is the same as yours Longhorn. Cap on radiator and overflow under cap. Yes there should be a hose running towards ground in case it does push out cap. As for the over flow or surge tank I believe only came with aluminium rads., without filler on radiator. I know my rad is original. It still has the OE# tag on it. The tank should be about half full. It leaves room for expansion.

I dont think it matters but I run my overflow hose into a bottle so the radiator can suck it back up as the coolant contracts.  You must have a two way radiator cap though.  This type of cap lets the fluid out via the seal that is under heavy spring tension to what the cap is rated at.  There is a small valve in the center if this under very small spring tension that allows the fluid back in.

So Terry, you have a hose running down or does yours have an alum. rad.? Duh...never mind. If yours has the tube under the rad. cap then it's not alum. I thought maybe that tube was susposed to go to a tank. I dunno.

 And Stephen... Good idea. I've been trying to get rid of that cat that curls up in the middle of my hood and cleans itself.  Here kitty kitty kitty

longhorn29438861.6476736111

"The Toy's" expansion tank cap has this on it:  Balkamp  703-1450  15 lbs

And there is an overflow hose on the exansion tank running straight down exiting below the frame just behind the control arm.  I like the idea of an overflow tank to catch any dribbles.

[QUOTE=longhorn294]

So Terry, you have a hose running down or does yours have an alum. rad.? Duh...never mind. If yours has the tube under the rad. cap then it's not alum. I thought maybe that tube was susposed to go to a tank. I dunno.

 And Stephen... Good idea. I've been trying to get rid of that cat that curls up in the middle of my hood and cleans itself.  Here kitty kitty kit  [/QUOTE]

I have a copper & brass 4 row radiator with of tube running down the side. Like others said, you can run tube to any type recovery bottle with proper cap.There is room for expansion in radiator however if you run a tank your rad needs to be full to the top. It will draw fluid out of tank as needed. Hope this helps, Terry

(fixed the QUOTE - Norsky)

Norsky38862.4117939815

 Got it. Thanks Terry