question for the experts who have seen everything

[deuce_roadster]

I recently was asked to supply a bare trans case to a friend who needed something to bolt to an engine to mount in an engine run stand. I have 4 or 5 empty side shift cases sitting in my spare parts and grabbed the first one I came to. I noticed it had a 39 lever on the clutch shaft. Thinking somebody along the way had it apart and put it in something else. When I was giving it to my buddy, I noticed the Factory stamped VIN was *99A-xxxxxxxxxxx*. This was clearly not a re stamp. Then I looked at the case and it had 01A-casting number on the lower back end. I can convince myself the clutch shaft and lever was changed but what 39 Merc had a column shift? What am I missing here? I am well aware the words "always" and "never" shouldn't be used with our old Fords but I am stumped!

[V8COOPMAN]

Interestingly, 1940 Merc 100 horsepower serials ran from 99A-101701 thru 99A-257100, and all on a "side shift" case, most-likely marked "01A". But what do I know....I sure AIN'T no expert! DD

[deuce_roadster]

Ah HA. I thought the 99A was 39 Merc. and 09A was 40 Merc. Thanks Dick!
This thing had a shift lever on the clutch shaft instead of the short linkage over to the frame the 40 Fords had, but like I said, anybody could have swapped that on there. I just couldn't figure how a 99A Vin was on an 01A case.

[V8COOPMAN]

I'm like you....I would have surmised that 99A- was '39 Merc also, with 09A- as a '40 Merc, and so on. But I guess in Ford-speak, part numbers ain't serial numbers. Mercury continued with this 99A- serial # prefix thru the '46 model year. In '47, the prefix changed to 799A-, and in '48 to 899A-. Almost makes your head hurt! Some of us know just enough about these numbers to be dangerous. DD

[V8COOPMAN]

Big revelation...……..It dawned on me layin' in bed last night that this just might have been a very early case of "One of Ford's Better Ideas". There IS a method to this "madness", and it all seems to revolve around the V8 (NOT V8-60) engines' HP rating. Of course, we all know that the first year for the V8 was 1932 which became known as the Model 18. Hence, all FORD V8s (excluding V8-60s) from 1932 thru 1942 were serial numbered with an "18-" prefix. Note that during the period from 1939 (the first Merc) through 1942 (the last year for an "18-" prefix for Fords), Ford and Mercury V8s had different horsepower ratings. With the introduction of the Mercury V8 in '39, it's horsepower was rated at 90 vs Ford's 85 horse. To differentiate the engine identities, Mercury cars were ID'd with a "99A-" prefix....that same 99A- prefix that many of us have always come to associate with a (first-year) 1939 Merc. Remember that the Mercs always had a higher HP rating than Fords between 1939 and 1942. Also remember that the '42 MERCS (serial # prefix 99A-) were rated at 100 horse vs '42 FORDS (serial prefix 18-) rated at 90 HP.


Ha....so when the boys returned from the "Big One", the first new model year offered was 1946 for The Ford Motor Co. The folks in the front office decided to make things a little easier to understand both for the production line workers, and for the new car buyers. Both Fords and Mercs would now share the same 100 HP engine. It's also notable to remember that the last '42 Merc of 100 HP was still serial-numbered as a 99A-. In 1946, the Merc's HP rating never changed from 1942 (still 100 HP), and Merc's serial number prefixes didn't change either for '46 (still 99A-). The '46 Fords however, were now using a 100 HP engine identical to the Mercs. What's really interesting here is the fact that '46 Fords had a change in HP from 1942....100 HP (like the '46 Merc) instead of 1942's 90 HP. Since the '46 Ford's engine was essentially uprated to match the Merc's carry-over 100 HP rating from '42, the Fords ALSO changed their serial number prefix to 99A- (matching the Mercury serial number prefixes). From 1946 thru 1948, Fords and Mercurys (both sharing the SAME 100 HP engine) now shared a common serial number prefix. We know that the serial numbers were originally stamped on the transmission of an engine/trans combination upon completion of that marriage. Only then were those serial #'s stamped into a Ford OR Merc chassis as the engine/trans was installed. With the engines and transmissions now (1946-'48) being identical, there was no need to maintain a different stockpile of engine/trans assemblies for a Ford or Mercury respectfully. So once the engines became identical, the serial number prefixes (between Ford and Merc) became identical also. All this time and I never realized such, until deuce made me dig a little bit. DD

[deuce_roadster]

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I'm now enlightened! It does make sense! Next time I see that case I will write down the actual number after 99A and look it up. it should zero in on the year. Thanks for having me think a little deeper!! All my old Ford experience ends at 1940 so I haven't dealt with anything newer. Now you can catch up on your sleep!

[rotorwrench]

Ford literature "the 1938 thru 41 Ford & Mercury chassis parts catalog" lists the Mercury 239 as a 95 HP engine. The Green Bible has things jumbled. They list 85 HP 221 blocks at 90HP and the 95HP 239 blocks as 100 HP. The G-series 6-cylinder is listed at 90 HP. I think these ratings were contingent on the engines all having the latest parts installed and that really confuses things. The Green Bible is a late post war publication with the last update in April of 1949 so it muddied the water a lot.

When the 1942 was introduced with the 11A advance unit & crab cap distributor and the new 21A camshaft, the ratings went to 90 HP on the 221 with and 100 HP on the 239 with no other major changes that I'm aware of. If it wasn't already confusing it just got more so.

The way I see it on the common V8 engines, the 221 never really got past the 85 HP mark. The 239 was mostly 95 HP up through the start of WWII. Post war, they were all 100 HP till 1949 when the 8CM engine showed up.