Quote Originally Posted by gal429460
ive got a 4 barrel 429 with d3ve a2a heads. i would say that this motor is all original. if i were to convert it to a 460 by fitting a 460 crank and standard style 460 pistons what would my new compression ratio be? is there an automatic increase in the compression ratio by going from a 429 to a 460 while still using the original d3ve heads? how is the 460 motor compared to the 429 in regards to its feel, performance, drivability, fuel economy, revs, or any other factors you can give me. thanks, paul.
The 1973 429 is the slowest, laziest 429 ever produced. Although all the individual parts you have in the engine can be massaged into fine perofmance engine parts for the street, the actual combination of those parts together (as in your engine) is a bad as the oem cobination can be.

Assuming that it IS a bone stock oem 1973 429 (and it sounds like it based on the heads, carb and the car from which it originated), you have a wimpy 7.6:1 compression ratio. Switching to the early-style heads (D0VE, C9VE or C8VE) will bump compression ratio to about 8.6:1 in this particular case. Doing this and also adding a timing chain set to pre-1972 specs will help measurably. So would porting the early-style heads prior to installing them. If you think you have a decent engine now, you are in for a big surpise once the changeover is made, as it is curretnly the doggiest of 429 motors.

Generally speaking, the 429 is a very smooth running engine and can last a long time. But the 1973 cobination is the worst offered of the 429s. My advice is to continue to run the engine if it is running fine, and in the meanwhile start learning about these engines and collecting the parts needed to give it some oomph or use when you rebuild.

Paul