V8 flathead cam stamp question

Does anyone know what T5 stamp is??

 

**** my bad it's acctually 5-T

 

That's what I thought but couldn't find any research on it. Thanks Steve

 

Yup factory stamp, no idea what it means, the stock cam in my 99A block had 5T on it, 39 motor, if that helps.

Hi lucky!

Hi Steve!

 

The cams with 5T on them I have had n.o.s. have been 48-6250 cams with the presson on cam gear. Does yours take the press on or the bolt on gear?

 

Mine was a press on.

 

When I was a youngster learning flathead lore the word was that 5T cams came from truck engines and were a slightly "hotter" profile than other stock cams. I've sometimes wondered if any of this was true or just folklore. I'm still none the wiser about the origins of 5T cams but, since yesterday, I now know how they differ from a stock 59T cam. Faced with a rainy afternoon and a bare block on the engine stand I got out a degree wheel, a dial gauge and a sheet of graph paper and set about checking some profiles. I chose a 5T cam and a C59T one with base circle diameters of all lobes measuring within a couple of thou of each other so I thought it safe to ***ume neither had been reground. Both cams were identified by a stamp on the front face and the same numbers and letters cast into the shaft. As it happened, one had a press-on gear and the other a bolt-on gear but I have 5T cams with both types.
The results of checking the profiles are shown in the accompanying graph. I used .020" checking clearances for no better reason than that I've always used it for checking flathead Ford cams
Three main differences were found between the two types of cams.
The C59T has about .015" more lift than the 5T.
The 5T has lobe centres of around 112 degrees compared with 105 for the C59T.
The 5T has around 15 degrees longer duration than the C59T.
How does this square with the legend that the 5T makes more power? I wouldn't mind betting the 5T does make a little more and probably higher in the rev range but I guess we'll never know until someone dynos the two of them back-to-back.

 

Great research! thanks for this.
I just got two more flatheads, a 99A (39 merc) and a C69A,( canadian wartime engine) both out of service for a long time, Ill add the cam types I find to this thread. I wouldn't mind betting the 5T was 99 prewar truck.