2 barrel 230 Intake Manifold

[maineSS]

I managed to locate the OEM 2 bbl carb 230 intake made by Dodge for a few '57 era cars (one was called the Westerner). I'll be posting some pics later next week.

I'm wondering if anybody on the Forum has tried using a modern single 2 bbl carb on the 230, and what their experiences were. Generally a bolt-on aluminum adapter is used, though some have reworked a single bbl manifold by opening up the top and attaching a plate with the new carb bolt pattern.

The 2 bbl manifold, along with the better flowing higher compression 57-59head allowed better high end hp, and were the final factory flathead devlopments before the OHV engine took over.

[Gordon Maney]

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[mannyc]

i have the same manifold

bought it when it became available. spoke to tom at langdons stovebolt speed shop. he sells a carb and offset studs to mount a new 2bbl carb. toyed with putting it on my command car, along with split exhaust and a better cam. electronic distributor and 1 wire alternator.

[mannyc]

2bbl manifold

i had mine machines on the back end to accept the standard dodge truck linkage. can use the stock bellcrank that way......

[maineSS]

Here we go with the OEM 2bbl pics (a bit late). These manifolds are quite rare, it took several years of looking before I found one. They were only made in small quantities at the very end of the flathead era for cars, and came with a 2bbl Carter that yielded 5hp extra in the upper rpm range.

The major advantage of using a 2bbl is better fuel economy in the low-midrange, along with more power in the upper end, as you can size the throttle bores for optimum airflow and velocity for the two ranges. Trying for max hp up top with a single barrel generally results in too big a bore for the low end, and optimum low end bore size chokes high end performance. If the carb/manifold combination works right, you can get better fuel economy and performance if your foot isn't always on the floor.

Pic #1 shows the top view of the 2bbl compared to the 1bbl (rusty one). The vacuum port boss on the 2bbl isn't threaded like the 1bbl, and neither are the linkage bosses on the side.

Pic #2 and #3 are rear and front views. More pics to com...

[maineSS]

Continuing on, pic #4 shows the bottom view, and pics #5 and #6 are a side view. Note the height and length of the 2bbl plenum compared to the 1bbl, it's the most noticeable difference between the two, along with the straight arms on the 2bbl vs the slightly curved ones on the 1bbl. The 2bbl will bolt up to the 1bbl exhaust manifold, fortunately there are no changes there.

The height of the carb mount above the tubes is 13/16" on the 1bbl, and 1 7/16" on the 2bbl. More tomorrow...

[mannyc]

my 2bbl intake

is difft than yours, but still factory. it has a drilled and tapped port on the manifold arm on the side closer to the firewall. there is no hole on the carb base with the pipe plug as is on yours. my threaded hole, had a hose barb fitting with a check valve in it. assume its vacuum for a auto tranny. i had my manifold drilled on the rear two bosses to accept standard ffpw throttle linkage. i will likely install it with a set of split stock exhaust manifolds.....

[mannyc]

What carb do you plan on running, MaineSS???

[maineSS]

Manny;

I don't know yet, it depends on what the base bolt pattern is, among other things. The 2bbl manifold bolt pattern is 3 1/4" x 1 7/8", which will likely need an adapter for modern carbs. Langdon sells a Holley/Weber model which has a progressive linkage, and supposedly works well.

Moving on, pic #7 shows a closer view of the carb mount and plenum entry. The oval shaped hole is 3 1/4" x 1 15/32", which tapers down to a 2" x 1 15/32" rectangle after a 1 9/64" drop. The 1 bbl manifold has a 1 19/64" dia hole, which yields an area of 2.236 sq in, vs the 2 bbl area of 2.937". The 2bbl has .701 sq in more area than the 1 bbl, which doesn't sound like much, but it gives more top end flow without bogging on the low end. More tomorrow...

[maineSS]

Pic #8 shows what would have to be done to the 1bbl manifold entry to equal the area of the 2bbl. The inked outlines are 9/32" back from the edge, and the same width as the 2bbl- 1 15/32". You'd have to cut these reliefs thru the top, then add an adapter plate with the 3 1/64" x 1 15/32" oval with the tapers to reproduce the 2bbl entry.

The big question is whether you'd cut thru the inside casting into the exhaust chamber, as the box appears to be hollow all the way up. The only way to find out is sonic testing or trying on a junk manifold. Since core shift happens, sonic testing would be best before carving a good manifold.

Both manifolds have 1 19/64" inlet ports into the head, so that is the ultimate limit of manifold flow. The key is to keep fuel in the airstream and off the manifold wall, and for this you need to keep velocity up and pay attention to how the flow turns corners. I'd try a sharp edge on inside cutout (nearest the engine) to shear fuel flowing down the wall, and perhaps taper the outside cutout from top to bottom to turn the flow if I had enough wall thickness.

It would be interesting to try a 1bbl manifold with Langdon's carb adapter vs the 2bbl using the same 2 bbl carb on the dyno. Theoretically, the 1bbl would come up short on the high end due to insufficient flow, but it might not play that way in real life. More tomorrow.... BTW, Gordon- what does "Subscribed!" mean- have I just won a free subscription?

[maineSS]

Going down into the 2bbl manifold, you will see a slight bump in the floor- pic #9 (indicated by the pen tip)-it's ~ 1/16" tall, and keeps liquid fuel on the heated manifold floor. The center port of the 2bbl slopes down, (pic #10), unlike the 1bbl (pic #11), which is level. If you look back at pics #2 &3 in post #5, you'll see the 1bbl manifold arms curve down, where the 2bbl's are level. The 2bbl plenum floor is 1/4" higher, which means the center port floor has to ramp down to bolt up at the same level as the 1bbl. If you've ever looked down the throat of the carb during warmup, you'll see a lake of liquid gas in the manifold, you want to keep that over the hot spot, hence the bump.

[Gordon Maney]

Good stuff....

[maineSS]

Looking at the entry to the manifold arms, we see a square-to-round transition (pic #12) vs the round entry of the 1bbl, which is visible from the outside if you look closely (pic #1 in post #5). I don't know what the reason for this is, I doubt it confers any special flow advantage.

The "U" shaped dip in the center port might cut flow a bit in the center port, which is not necessarily a bad thing from the mixture distribution standpoint, as this manifold is the classic example of "rich in the middle, lean at the ends" configuration. The later Slant Six intake shows an effort to better equalize intake flow between center and end cylinders. More later...

[Frozen Parts]

The 230 in the '56 Coronet came with a 2bbl manifold and a Bendix/Stromberg WW. So that is a possible source of a 2 bbl manifold. The manifold is all set up for the WW, and those carbs are fairly easy to get parts for. I rebuilt mine when I found about a half inch of goop in the bottom of the float bowl. That is what is in the '53 B-4-PW-126 that I am fixing up. It puts out 130HP versus the original T-137s 90HP. The only real fly in the ointment is that it has a front sump oil pan. You can put just about any oil pan on just about any 230 though. That particular engine can be identified by its number on the upper left side. It should begin with D62.

[tbone1004]

that looks awesome man! would love to get one of those for my M37... Hey, if you want to grab a beer at somepoint, shoot me an email, would love to meet someone else in Maine with the same interests! tmnelson@ncsu.edu