I have been wondering about the same thing {The purpose of the electric 
fan for the heating} in my '74 van. I replaced the hoses and checked all 
the vents but it doesn't seem to deliver much volume. You can sure hear 
that fan a-roaring, tho! 

I have had a problem occur while driving on a few occasions and was 
wondering if anyone has had the same thing happen. My van has an 1800 
with dual carbs and is a standard {ain't they all?}. What happens is I'll 
be driving along the freeway at night, flat out and all of a sudden the 
engine starts to lose power and seems to sputter/miss with little 
backfires. Ihave to gear down...in 3rd I can keep it going not bad but it 
runs real rough. What I end up doing is pulling off to the side, leave 
the engine run and give it a few good revs, then let it sit running for 
5-10 minutes before driving again. This usally works for the rest of the 
trip; sometimes I have to do it more often. It only happens at night! I 
have replaces all the fuel lines, new filters, checked the fuel pump 
filter, replaced the plugs and hade the timing set. I can't think what 
else it could be, except maybe the carbs? Any help would be greatly 
appreciated!

Dharmabum