What is original use of "29 AR" cylinder head
 

I have what appears to be an original complete engine with '59' on bell housing and cylinder heads marked with '29 'AR' in stamped letters off center. I assume this is a 1942 Mercury engine but most 1942 Mercury heads have '29' in raised letters in center of head. Does anyone know what the original purpose of these heads would be?
40larry

Re: What is original use of "29 AR" cylinder head
 

Larry, Can you either email me a photo or post one? I seem to recall having notes about these but my memory needs a "slap".

Re: What is original use of "29 AR" cylinder head
 

Hi Larry,

interesting. I believe 29A heads are mercury. I have a pair, marked 29A-LH and 29A-RH.
these are center of head and are just left and right.

Could you post a photo of yours?

Re: What is original use of "29 AR" cylinder head
 

Generally the letter S is used in the prefix of "special" cylinder heads. These were generally for higher altitude and higher performance "Police Package" applications. In the 81A family, they are referred to as "Denver Heads". With "A" being a passenger car reference and "T" being for Truck, the S was added on the end but I don't think they made any high compression truck heads since that would not have been practical. The 95 horse power 239 engines were used in both passenger cars (mostly Mercury) and optionally in trucks but trucks sometimes had relieved blocks to lower the compression so as to minimize detonation under high loads.

29A indicates the 1942 Mercury passenger car engine but the 1942 production was limited by the war starting in February of 1942. V8 production was more limited after that but the 21A and 29A engines were likely used for some wartime applications here is the US. Canada produced more of them than the US did in that time frame. Ford US produced lots of 1.5-ton trucks but they had the G-series 6-cylinder in them. The scout cars and US version of the Universal Carrier had V8s. Bomb loaders and Burma Jeeps were also produced. I don't know how many large trucks were made but I'm sure they made some for buss and fire truck conversions. Ford also made the big twin engine semi-tractors to haul B-24 partial completions down to Dallas, TX.