toolmanmike said

I wonder what's going on there. All 64-7 273's had solid lifter cams. The hydraulics didn't come out until 68 when the LA 318 was released and the 273 followed suit. The 273 was dropped in 69. I think the 4 barrel pistons and the increase in compression is one more thing on the list to make the 273 run even better. The compression, slightly bigger cam, 4 barrel carb, the dual point (to a lesser degree) and the HP exhaust all worked as a team to make the 235 hp that Mopar advertised. If you have to bore the block, why not use the higher compression pistons? The difference between 8:1 and 9.5:1 is a sizable difference.

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