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.
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.
272 was never a Thunderbird engine. Even in 1955 all T-birds had 292’s. In 56 the 292’s and 312’s in the passenger cars were all called Thunderbird on the fender badge and rocker cover but the 272 equipt cars had the V8 fender emblem of the 55 y-block and did not have Thunderbird on the rockers. Good luck on the LM ignition. Not sure on what will happen install a Pertronix on the LM plate. I changed to a 57 up ignition and used a Cater WCFB and never looked back.
Putting the petronix in does nothing but eliminate the points. You’ll really need either the right matching carb (not a 56, not a 292, a 55 272) or a proper distributor. There’s been a lot on those over at yblocksforever, lately the CRT unit. Start here. http://forums.y-blocksforever.com/Topic168886.aspx
Sorry Guyz but i was not clear (and I’m not quite as dumb as you may think) the owner has ordered a Pertronix distributor not just a module (it may be a complete Pertronix distributor or it may be a CRT with a Pertronix module in it, or it may be some other distributor with the module in it, all I know is what I’m told (I told him that we needed a distributor for a 57 or newer motor, I did not tell him to buy one or what to buy, I thought he was waiting for me but he pulled the trigger and then told me about it after the fact)) (I followed up with that link Mike, thank you). So, as yet nobody has made even a feeble attempt at my original question. Has anybody even read the original question or just responding to the most recent post? A 48 originally had 48 jets and a 63 PV, the PV in this carb (new repop I believe) is not marked at all, which is not unusual. I did not have my jet wrench with me so don’t have the jets out yet however I’m going to assume that they aren’t marked either. I plan to buy jets and a power valve that are properly marked so that I know what I have. It’s late and I’m going to bed, I’ll pick this up in the morning.
While I personally prefer the Stromberg (if genuine) to the Holley, the Stromberg EE-1 "48" is SMALLER than the smallest Holley used on the 272. The 272 was the base V-8, not referred to as a "Thunderbird". The 292 was referred to as a "Thunderbird V-8" whether it was used in a Thunderbird or a Ford passenger, as was the later 312. Suggestion: If you are installing a pertronix, UPGRADE to an alternator!!! As to your original question: When migrating an O.E. carburetor to a non-standard application, ALWAYS start with the ORIGINAL CALIBRATION for the carburetor, and tune from there. By doing so, you have a repeatable "baseline". Jon
Thank you Car, I had been thinking the same thing. This motor is in a (Fiberglass) 32 roadster “hot rod”that is just now being brought to life after a 2 year build. It does have an alternator already so that’s been handled. I know that a 48 is smaller than the smallest carb Ford ever put on a Y block but it would have all the power (and more) then the 79 year old owner will ever use by quite a lot. This is an old skool “budget” build that is basically a cars and coffee rig. The owner wants to do this (at least for now) and I’m just along to help “Dial In” the motor as that is not in the owners bag of tricks. I was told it was a “Thunderbird Motor” but I should have left that out because I had not confirmed it for myself and it didn’t really matter for this discussion anyway, it just confused things. I appreciate all the help guys, I really do. Carbking, would you be a source for parts (jets, power valves, maybe a jet wrench)?
I don’t think it was in that link, but take a close look at the distributor when it shows up. Some reports of unit sold as yblocks, but based on sbf cores. The shaft length or gear placement is wrong. Mostly short, but I saw mention of one that was long. Bottomed out in the block at the cam gear and ground things away. Petronix and CRT’s are probably ok, but since you’re not sure.?
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