Is there a significant difference between 37-48 & 49-53 intake manifolds? I'm assuming that an earlier one will not work on the later 8BA?
Crankcase ventilation is different on the two engines. Later (48 & up Truck and 49 & lup car) used a road draft tube instead of a vent on the pan. You could install a PCV setup and use the later manifold and block off the road draft tube. Jim
You can put an early intake on a later engine, but you must use the early fuel pump stand and fuel pump. There is a breather with that set up. Probably not perfect , but it will work. There are also more bolts on the early manifold, so you'll have several empty holes.
Another difference not mentioned yet is the carb mounting pad angle. Early engines sat level in the chassis, so the carb bases were flat or parrellel to the block, while late engines are angled down in the rear with about a 3 degree tilt, so the carb bases are tilted to the front to level the carb. Some aftermarket intakes have both styles or designs, while others, like Navarro, have most/all bases flat or level. Using a late-style tilted intake on an engine sitting level results in the carb(s) angled forward and looking somewhat odd; using an early intake on a '49-'53 car results in the carb(s) angled to the rear. Vehicle chassis angle plays into this also. My '32 in the picture has the engine angled almost 5 drgrees, but the car is raked over 3 degrees, so the engine and Navarro flat intake sit with less than 2 degrees tilt. Just sompin' more to think about when choosing a flathead intake. Bob
The Bolt thing is not entirely true count the intake mounting holes on this 8BA motor it has 10 a side as per the early blocks.
the generator mounting pad on the intake too, when I ran a 34 or 36 intake on my 8BA I had to make some plates to space the generator out to line up with the water pump pulleys.
The tube in the valve chest to the road draft tube sticks up above the manifold deck on the block. I ground the inside of the manifold a bit so it would sit flat and still allow the crankcase ventilation when I planned an early style Edlebrock 2 deuce on an 8BA. I drilled and tapped a hole in the manifold for a 3/8 npt to 3/8 tube next to the vent tube area to which I added hose, a pcv and another length of hose to the air cleaner base. Without some ventilation, I think you'll get oil blowing out the vent in the oil pan on the 59 block. Then I decided on the 4 bbl and new 8BA manifold and the sedan is happy with that.
heres some info I did ages ago. might help some. http://www.jalopyjournal.com/forum/showthread.php?t=168843&highlight=flathead+basics