The one that starts with 43y i think partially matches up with the vin. Everything i researched showed a letter for second digit. Trying to figure out what it came out of and hp rating. Has a XS on head surface. That indicates a 1973 i believe. 1973 had 2 different applications for XS. One dual exhaust and the other non dual exhaust . The other one where i marked 1 i haven't the slightest clue what that indicates. Thanks for the help!
Can you show a pic of the xs on the head mating surface by the oil dipstick. If it is xs you have a 73 stage 1 block. The last five numbers on the face of the block will match the cars vin.
View attachment 627282 I AM MISTAKEN! It is a XF stamp with 449 stamped next to the XF. According to info I was able to glean off the web one XF is rated at 225 hp 8.5:1 , the other is dual exhaust 250 hp 8.5:1 compression. Sorry for the confusion on my part
I don't agree with that 100%. My documented stage-1 is a XS, wonder if the Riviera stage-1 is the XA. Fernando
For the Stage motor, looks like the big cars Riviera and possibly the Electra got the XA. The gran sports got the XS, from what I gathered. That document should be corrected! They should both say stage-1 with a body code to determine the codes. Plus under the Transmission column for the XS should also have both manual and 3 speed auto. Fernando
Due to the extra weight of the Riviera a slightly different camshaft was used in the Stage 1 engine to increase torque to get the car moving. This is the reason for the seperate Stage 1 engine code. This camshaft has 3 grooves ground behind the cam instead of just 1.
