Well, I measured dish for the 1971 pistons tonight. Came out of block 1231738. Getting 33-34cc volume and about 0.25” dish depth.
Anybody ever give in to the temptation to grind off that nipple? Thats one ugly slug u got there. I bet the top of the intake valves had a carbon party growing on them.
Oh yeah, it was a huge party. Everyone was there. This was one of the cleaner pistons. Grind off a nipple?...... lol. Seriously though, that is one big nipple. I’ve heard of one guy doing that but don’t know the results. I wonder if Just smoothing the sharp edges would help. Either way, I’m likely not using these. Too much dish for me.
So your looking at about 1 CC per every .007" of dish that diameter. If your looking at custom Pistons to up the comp to a street friendly max of 9.4 to one then get it made to give you some good quench, as in a D shaped dish!
Interesting, my 4.3525 bore speedpro/ta forged pistons measure 21.5-22cc and ta mills the Nipple off these pistons, not sure why its even there unless it was for production or something?
Yes, one of my old ones. I was curious about which piston version GM used in 71. Looks like the same version ("B") was used at least up until 73.
My accuracy is probably within 0.5cc. My syringe has 2cc gradations. Plus all the carbon deposits and maybe mine is closer to 35cc like Scott measured.
