The tag is from a commercial engine rebuilding shop. We have one (a independent commercial engine rebuilding shop) in East Tampa that rebuilds your motor or sells you one off the shelf taking your motor as a core to rebuild for their next customer. The tag identifies their shop and I would imagine is used so far as the limited warranty. It is not from a "big Name" independent shop like Sony Leonard, Bill Mitchell, John Lingenfelter, Bill "Grumpy" Jenkins Competition, or the ilk. Just a standard reliable we can get you going again shop the specializes in building motors (you may be able to research who bought that motor from their records if they are still in business and kept records that far back).
As far as the rear end goes those code numbers and letters decode as follows. I am more inclined to think that may be the axle code is from something earlier than 1965 or older than 1977 which is the range I checked.
FP - states that this was a 1966 Chevy II 12 bolt open rear end with 3.73:1 gears. If so it would be exceptionally narrow. Hard to believe it would work under an Impala.
9 - indicates the month of the build
23 - indicates that it was built on the 23rd of September
G - states that it was built by Detroit Gear & Axle
As to the cowl tag :
BT indicates the car was built in Arlington Texas
10E indicates it was built in the fifth week of October
66 -16837 decodes as a1966 Impala SS Two Door Sport Coupe
2532XXXX Is your partial VIN (sequence number in line being built)
HH-6 indicates an exterior body color of Medium Green with the 6 indicating another option such as Vinyl roof but I can not find the info. It was not a two tone car.
885 6 indicates a White interior color 6 says vinyl bucket seats.
C60 is a vehicle identification trim code that is not published in order for Judges and "experts" to identify bogus trim codes from the real article. They were all unique to the plant and instructed the assembler as to any variations from the normal build to meet a customers order.
I have no books to trace your carb back to see if it came with the motor But I suspect there is a good chance it did, since it does not show a rebuild tag in the picture, and has not been replaced by the usual Holley carb.
As to horse power Oval port heads which I suspect you have are rated at either 325 or 350 horse depending upon the cam.
Last edited by Big Dave; 12-22-2007 at 05:51 PM.