Old Grancor Automotive receipt

[sidevalve8ba]

I was going through some papers I found in an old filing cabinet of my father's yesterday and found something interesting. Dad died over thirty years ago but I remember him telling me about a '49 Ford he had when we moved to Virginia from East Texas. He said he had "done a little work" on it to "make it a little peppier" as I remember it. Anyway I ran across this receipt that I thought some of you might like to see.

I am assuming it is for high compression heads, dual exhaust and an intake and 8CM carb but I am unclear on what a "DSM unit" is. Maybe someone could clear that up for me.