What's the purpose of this port on 906/452 heads?

[bull]

Sorry if this is a dumb question but I was looking at this one horseshoe-shaped port on some 906 heads and wondering what its purpose is other than to collect dirt? It doesn't seem to go anywhere so what's it for?

[Dans 68]

No purpose, I believe. The below photo of another 383 build-up shows that area is painted and thus inert (no oil or coolant access) to any engine mechanical function.

Dan

[bull]

Well, now that picture's got me wondering about the valley. Is that area typically painted?

[Dans 68]

I don't think it matters. This engine was obviously taped off at all the important areas, and spray painted. My take on it is that it is simply a preference of the builder. I have attached another of the build, and the link to the photos and article. http://www.hotrod.com/techarticles/engine/hrdp_0711_mopar_383/photo_01.html

Dan

[Rolling_Thunder]

it is to catch the nuts you use to hold the carb down...         

[bull]

it is to catch the nuts you use to hold the carb down...         

Funny you say that because I recently found a "spare" nut in one of mine.

[tan top]

it is to catch the nuts you use to hold the carb down...         

true 

[lisiecki1]

Well, now that picture's got me wondering about the valley. Is that area typically painted?

I high temp coat the inside of the blocks on the engines I build, I read somewhere that it helps the oil drain back quicker since it's running down a slicker surface 

[68r/t]

Well, now that picture's got me wondering about the valley. Is that area typically painted?

The painted valley is sometimes done by hotroders so the oil can return back to the sump a little quicker, same as some people polish the same areas with a die grinder.

The port on the head seams to be a air gap around the exhaust crossover, it is a good dirt collector.

[Nacho-RT74]

it is to catch the nuts you use to hold the carb down...         

also carb clips, retainers... LOL ( BTDT )

[bull]

Well, I guess the main purpose of this port is for heat dissipation. That's all I can think of.

[Nacho-RT74]

those are my thoughts too

[375instroke]

It's a thermal break to reduce the exhaust heat from entering the head.

[Challenger340]

It's a thermal break to reduce the exhaust heat from entering the head.

What he said !

The small oval/round port is the Exhaust Heay Crossover, where HOT exhaust gases are actually channelled "UP" under the Intake to warm the Carb.
The "Horse shoe" port above it is as 375INSTROKE said, thermal Break between the crossover and the rest of the Head.