1975 chevy 400 small block RPO

[Roberts64]

Just bought a 400 small block and I'm trying to learn what it came out of with the RPO AND LAST 6 DIGITS

15R494904

Other number on same pad is 

T0428CTX

Any help would be very appreciated

[newdude]

15R494904.

 

1 - Chevrolet.  First digit identifies the make.

5 - 1975.  Second digit is the model year.

R - Arlington Assembly.  Third digit identifies the vehicle's assembly plant.

494904 - Production sequence for the vehicle.

 

T0428CTX.

 

T - Tonawanda.  First digit identifies the engine's assembly plant.

04 - April.  Second and third digits identify the month of the year built.

30 - 30th.  Fourth and fifth digits identify the day of the month built.  So April 30th.

CTX - A,B.  The last three digits identify the car line the engine was used in.  CTX represents A and B body vehicles. 

 

The RPO code seems to be LT4.  4 barrel carb, 175hp.   

 

So.  GM and Wikipedia seem to disagree on some of the Chevrolet products built in the plant so I've linked both sources:

 

GM - https://plants.gm.com/Facilities/public/us/en/arlington/about_us.html

 

Wikipedia - https://en.wikipedia.org/wiki/Arlington_Assembly

 

Being the engine VIN is a Chevrolet, you've got an engine from of the following:

 

- Caprice

- Chevelle

- Monte Carlo

- El Camino

 

Edited March 26, 2019 by newdude