- 2,052
- 57
- 48
- Location
- Milford / Michigan
17:1 is the tractor compression ratio. However, this wouldn't 't explain the blow-by. A cracked head wouldn't explain the consistent low compression pressure. Are you guys even reading his posts?
I can't swe it being a cracked head especially since they were NOS when I put them on. I strongly believe the 17:1 pistons were a different shape and did not have the dish in the piston that we are used to seeing with the multifuel piston. The early 20:1 compression pistons were in early production engines and then eventually wereally replaced by 22:1 compression pistons for the rest of the multifuel production years.