Engine number question

[104thLRSD]

First and foremost; I hope everyone is doing ok and staying safe during the pandemic.

Question for any engine number gurus.

I have a 1968 GTX assembled April 19 68.
I have limited history on the car.
The 440 RB occupying the engine bay cast # 2536430-7 was cast 5/27/68. The stamped Serial number by the oil pan rail shows this number PT440P25120928. That indicates the 10,000 day julian date as June 13 68. This matches the front ID pad. However there is no “HP” stamp in that pad. Only D 440 6 13 and a double stamped B. Obviously not the original engine from the date. I also sanded the paint on the passenger side vin pad. Nothing. I dont believe a number was ever stamped there. I can not find evidence of any partial vin by the oil sending unit either. So I cant figure out what kind of vehicle this engine came from. I have read in several articles that the extra “P” in the serial number indicates premium fuel which i think means HP
Is that true? Does this mean the engine is a HP? Even though it is not stamped as such?
I also noticed that the engine was originally painted orange.
Any thoughts?

 

[turbine68rt]

Most likely from a very late build non-hp '68 440. Possibly from a C-body. Even if there were numbers stamped by the op sender it would only be the last 8 digits of the VIN.

 

[104thLRSD]

Does that mean it is only 350 horse power or is it still 375. Sorry if that is a stupid question.

 

[turbine68rt]

If it was never disassembled It's doubtful it's the 375hp version. However, if the heads, intake, carb, [new replacement] cam/lifters, exhaust manifolds were swapped from the original engine that would be beneficial. Check the casting dates on your intake and exhaust manifolds as well as the carb tag numbers. PT---Trenton plant.

 

[104thLRSD]

Ok. Thank you for the info. It was rebuilt at some point and a mild cam was installed along with an edlebrock intake and holly carb. But this makes sense though. The torqueflite is from a 1969 polara/monaco and the radiator is a 1969 part number. So they may have swapped out everything at some point. Thanks again.

 

[104thLRSD]

Turbine68rt,
Drivers side exhaust 2843992
Passenger side 3806900

 

[Curiousyellow71]

The blocks are identical between hp and non hp, 440 castings had some change from year to year, but the block, heads and intake should be identical from what the car was born with if they are both 68 440s. 350hp is likely what it was without the hp stamp. But, I believe all 68-69 440s received the same pistons so they both would be premium gas engines with 10.1:1 "advertised" compression. Since you don't have a original carb it doesnt matter but I think the 350hp maybe could get 4160 holley or a avs(I've only seen the avs)...and the hp got only carter avs. On the AVS they listed 3 different numbers, manual transmission, automatic and automatic a/c. The non HP engines had log style manifolds a smaller cam, no windage tray, diff. valve springs w no dampner and stock timing chain.

 

[104thLRSD]

Thank you guys. Great info. I was kind of led down a false path when I purchased it last year. (Should have educated myself prior) Its taken me this long to figure all this stuff out and find numbers. But its a great car and at least the rad support and trunk lip numbers match the fender tag. Thanks again for all the help.