Hello all, I'm new to the Form and I've been working on Hot Rod's since I was 10 year's old (I'm 57 now) with my Dad and need some help to find out my CR on my 327 for my 63 C10 pick-up. I've read many of the replies but didn't see one like my problem. I had my 327 rebuilt at the machine shop and I told the shop owner what type of flat top pistons I wanted & wanted the blocked decked & bored & heads milled & rebuilt. But he did NOT deck the block and after the total rebuild was completed I found this out and also found out that the pistons used where not the ones I wanted. So long story short I was compensated for the errors and took my engine home. Sooo The pistons are KB 1423-030 cast rebuilder type with .015 steel shm head gaskets & 3.25 strk & 5.7 rods & 461 heads shaved down (not sure how much he couldn't remember). The pistons set down into the cylinder hole and are NOT flush with block deck I've been told so if that's true I have no idea what my CR is because the block was NOT decked. I've used the formally that the Cam companies use but I know it's not correct cuz it doesn't account for the Piston setting down more in the hole. So i hope someone can help me figure out the correct CR. I hope I've given enough information. Thank you for your time and help, From 1Nimrod
Hello 1Nimrod. Welcome to the site. You may want to move this post to the "Hokey Ass Message Board" to get more visibility and input. https://www.jalopyjournal.com/forum/forums/the-hokey-ass-message-board.5/ Mike
You could have a much better guess if you knew how far below the deck the pistons are. The summit racing website has a compression ratio calculator. I'll attempt to attach a photo showing the inputs in their calculator.
I was told by the company that made the pistons (Silvolite aka KB) that total was .045 including the factory deck hight .025+.020=.045 total down in the cylinder hole. So with my .015 beaded steel head gasket I have a total of .045+.015=.060 total but with the CR calculator it doesn't acount for the piston setting lower.(the one I used was Summits calculator it looks just like the one you posted) thank you for your help. "Merry Christmas All" From 1Nimrod
I'm trying to figure out the correct CR so I can get the correct cam. Blacky Fifty I don't know how to move it to the other area you mentioned because I'm very GREEN to this technology I'm using my phone that my oldest daughter and son-in-law gave me it's all NEW to me just learning as I go along,thank you for your help. From 1Nimrod Merry Christmas everyone...
The Jalopy Journal
