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I have a OEM 4bbl intake on my engine and it has a tube coming out of it.
Does anyone have an idea as to what the tube is for and what this cap is?
the attached pictures i pulled off of the internet along with the number but it sounds like
my intake may be a pre 64 off of a Tbird. The tube I’m talking about is on the top right of the manifold in this picture. The tube and breather is on the bottom left of this picture
'64 might have had a PCV system, or a road draft tube. I don't see the road draft tube remnants on the back of that manifold. Breathers and fill ports moved to the valve covers in '65.
EDIT: Road draft tube goes straight out the back, see pics in post 4
Also, '65 might have been the change over from the expansion tank sitting on the engine to the left of the distributor, so that could explain the t-stat housing difference.
That's an interesting observation. If the later thermostat and housing is smaller and won't fit the early intake, and the expansion tank was used on all the early, pre 65 applications, (full size and Thunderbird), there may not be a typical thermostat housing for that intake and you may have to use an expansion tank with that intake. I'll be interesting in your findings.
As I’ve learned and as it’s been stated, in late 66 early 67, the intake and head ports were
downsized and the thermostat itself and housing went from 2.5 inches to 2 1/8th inches. Simpler put there are two sizes. Big and small.
I found a company that sells reproductions of the big thermostat housings and purchased one as well as a thermostat.
As I’ve learned and as it’s been stated, in late 66 early 67, the intake and head ports were
downsized and the thermostat itself and housing went from 2.5 inches to 2 1/8th inches. Simpler put there are two sizes. Big and small.
I found a company that sells reproductions of the big thermostat housings and purchased one as well as a thermostat.
The 2.5 inch thermostat is the key but the housing isn’t going to work as it is unless maybe I double up on the gasket. The housing is not recessed for the thermostat.
I am going to take the housing into a machine shop tomorrow and see if they can mill it out.
