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10:1 Compression
https://www.slantsix.org/forum/viewtopic.php?t=6420		 Page 1 of 1
Author:  65Dart270 [ Sat Aug 02, 2003 5:36 am ]
Post subject:  10:1 Compression
How much milling/cutting would have to be done to bring a 225 close to 10:1 CR? Are there any forged offerings out there in pistons that would help achieve that goal, and what mechanical cam would you guys recommend for a 10:1 street motor? I have been hiding over @Moparts, and even though I like the board, I have decided that building the cookie-cutter 12 sec. small block has been done to death, and would like to build my /6 Dart into a formidable street machine. It must have been all the trash talking between Slantzilla and valcuda! :roll:
Author:  Hemlocke [ Sat Aug 02, 2003 6:05 am ]
Post subject:  OK, now we are cooking with fire!
Sorry, I couldn't remember my user name here, and I used my name from Moparts. If there is a 65Dart270 here, and I used your name, it was an innocent mistake. Still asking the burning question, though, just with the correct username. :D
Author:  Doctor Dodge [ Sat Aug 02, 2003 9:03 am ]
Post subject: 
Great to see that you realize the difference between building a quick Slant vs another quick small block. You will always get more "attention" when you pop the hood and show them the Slant.

Ok, on the piston question, the "long rod" 225 build-up is the quick and easy way to get 10 / 11 to 1 compression range with no head or block milling. KB has some decent hypereutectic that make for a pretty good build-up. See the Stroking article in the articles section of the site for more info.

As for forged piston for the stock 225 con rod, all have been discontinued but there are some "floating around" if you look hard. (Cox Boys?)

Most of the racers just order custom pistons, put the CR right where you want it and use the 2.2 Turbo "thin" (metric) piston rings for less friction.
Keep asking questions, See if you can find a set if 198 con rods (1970-74 base engine vehicles) the long rod combo is a well proven combo that works well.
DD
Author:  Al T [ Sat Aug 02, 2003 10:11 am ]
Post subject:  Static Compression Calculator Exel Spreadsheet
I put this together if you're interested in help with the math.

http://www.slantsix.org/forum/viewtopic ... ght=#23519
Author:  Dart270 [ Sat Aug 02, 2003 1:51 pm ]
Post subject: 
FYI, you can get about 10:1 by milling about 0.110"-0.120" off the head or block. I have done this with stock replacement cast pistons on my two motors and it is cheap and effective HP. Measure your specific motor's specs (deck height, gasket thickness...) and use Al's calculator to get a good idea of what to mill.

Mine are actually 0.080"/0.180" angle milled (intake side and plug side numbers, respectively) to give about 10.8:1 on stock "spec" deck height (0.140" piston top to deck at TDC).

Lou
Author:  65Dart270 [ Sun Aug 03, 2003 5:50 am ]
Post subject:  Thanks a bunch
Thanks, guys, I appreciate the posts. Very helpful indeed. I am going to continue upgrading suspension, chassis, and the transmission, and start accumulating the parts for the motor for a spring buildup. I appreciate the quick responses, as they will help me determine my direction.
Author:  SCOOTERTHEDOG [ Tue Aug 05, 2003 9:08 pm ]
Post subject:  cr
easy way to figure cr at 10 to 1 on 225 is about zero deck ht 54 cc's and a .020 gasket it will bring ya pretty close
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