Technical Stromberg 48 on a 272 “Y” block

I am assisting a friend with setting up his 272 “Thunderbird” Y block (in a ‘32 roadster). At least temporarily we are going to be using a single Stromberg 48. We have not yet reached the point of starting the motor so I can’t say how it is performing. I have not yet opened up the 48 to see what PV and Main Jets are currently in it (I will be doing that in a day or two). I would be interested in getting advice about what PV and Jets to use as a starting point (FWIW a T5 is the transmission that has been installed). The motor is “stock” for whatever a 272 “Thunderbird” motor was/is (with dual exhaust and free flow mufflers). I have a A/F meter and we have installed bungs in both exhaust pipes right below the Rams Horn manifolds.

 

You have other problems. If the 272 is pre-57, it will have (stock) a "Load-A-Matic" distributor, which relies on a special combination of ported and venturi vacuum to operate the advance (they have NO centrifugal advance). This special signal is supplied by a port on the original carburetor. The "48" does not have this port, so you will have NO advance. And don't think that you can cheat by substituting manifold vacuum, because that will make things even worse.

You can get around this by using a later model or maybe even an aftermarket (Mallory) distributor.

 

I am familiar with that distributor and it is something else I am going to be dealing with (today is going to be my first opportunity to get my hands on this motor).
The distributor rotates CCW on this motor as well which may help determine what year it is.

 

I was originally told that only the earliest Y blocks used a CCW distributor rotation but I don’t think that that is correct. I think that they were all CCW. As I said, I am familiar with the Load-A-Matic (I have replaced them on flatheads) but I actually appreciate the reminder. That is something that I can move to the top of my list to check on. Thanks.

 

Most distributors use centrifugal advance to move the timing ahead as engine speed increases. They have a set of weights either under the rotor or under the points plate. As speed increases, the weights move out and move the rotor back advancing the timing. The Load-O-Matic has a fixed shaft that the rotor mounts on; it can't move. To advance the spark relative to engine speed, Ford used a venturi vacuum signal to the vacuum canister to move the points plate. That signal is taken from the throat of the carb. As engine speed increases and more air moves through the carb, venturi vacuum increases. It acts the same as the centrifugal setup. If you do not have a venturi signal, you won't have any advance relative to engine speed. The engine will run, but not as well as it should.

 

Yes, they all turn CCW. The only difference I know of on the earliest distributors is the '54 Fords had a drive gear with a different number of teeth.

 

A used Holley 94 is cheap and a tremendously better carb.

 

The motor does indeed have the L a M dist so we have a Pertronix on the way.

 

I don’t disagree with you Andy but the owner has a brand new 48 and want’s to use it at least for now.