36 vs. 35 40 series exhaust manifold question.

[Buick35]

I just got a replacement crack free manifold for my 35 40 series.I believe it's from a 36 or later. Everything is identical except the one I just got has about a four inch tall tube or pipe on the top of it going straight up.My old manifold doesn't have it.It looks like it's only open at the top and sits a little bit behind the carburetor so I think it will be alright. Anyway,I  just wondered what it's for. An air cleaner fitting mabe?

[Matt Harwood]

Heat riser for the choke on the carburetor. There should be an insulated tube that connects it to the choke. It shouldn't affect anything on your car and you could probably trim it to make it less noticeable. 

[Buick35]

20 minutes ago, Matt Harwood said:

Heat riser for the choke on the carburetor. There should be an insulated tube that connects it to the choke. It shouldn't affect anything on your car and you could probably trim it to make it less noticeable. 

Thanks,Now I know.

[Jim Nelson]

Greg,   How about a pix of your 35-40 series manifold and the other one.   That newer one you have has the heat riser tube to provide heat for your choke assembly.     Since you live in Florida - you don't need a choke.   Having a second throttle to hold the engine around 1500 when you first start and then you slowly push in that throttle until your regular foot feed takes over.   I have gotten rid of that automatic choke assembly because we don't need it down here.   I took the cable from the dash that was suppose to manually adjust the ignition retard or advance and the 50 series helps that.    Moving the end from the distributor end and replacing it with a normal push/pull  lawn mower cable has worked for me.    See my pix of the secondary throttle control  far left side.  

[Buick35]

Thanks,Good idea.

[Buick35]

The newer exhaust manifold bolts up nicely to the intake manifold but some of the intake and exhaust ports aren't quite paralel with each other vertically.I haven't tried to install it on the car yet.I wanted to take it to a machine shop to make sure the surfaces are flat.If I bolt it to the block first with the intake and exhaust mating surface slightly loose that might help,I hope.