E-mail [email protected]
Toll Free 800-341-1528
CNC Competition SB Chevy 400/383 Short block, GM Steel Crank, Scat Pro Comp Rods, KB 12.1:1 Pistons
Here at CNC-Motorsports our short blocks start with premium cores. We then clean, magnaflux, and sonic test the thrust sides of the cylinder walls for a minimum of .200" thickness after overbore. All blocks are then line honed to get a baseline for all of the BHJ blueprinting fixtures. From this point we square up the decks using BHJ's Blok-Tru to get the desired deck heights. Once this is done we bore the block using BHJ's Bore-Tru to get the desired spacing. There are quite a few blocks that are not able to have this done, due to they are either to far off from the factory or previously bored in the past. Either way we utilize this procedure when possible.
The next step in the process is using BHJ's Lifter-Tru set up to correct any misalignment in the lifter bores. Most Chevy blocks are taken to the next size lifter bore, which is the Ford style .875 lifter, this is the most cost efficient. We can also re-sleeve lifter bores if needed or preferred. The next step is the honing process. We install main caps and torque plates to ensure cylinder bores ends up as true to actual running conditions as possible. In our honing process we aim for around 30º crosshatch to achieve the most compression while still allowing the rings to travel. Bores are measured with plates still attached and recorded on the blue print sheet.
Once all the machine work is completed, the block is washed and prepped for assembly. During the assembly process, all components are measured and corrected to obtain correct clearances. All of these measurements are recorded on the blueprint sheet.
Rotating assemblies in these short blocks are all weight matched within 2 grams, and the crankshaft is balanced with in ½ of a gram.
Here at CNC Motorsports we strive for excellance in our craftsmanship to provide our customers with the performance parts at a perfect price.
SB Chevy 400 Destroked 377 3.480" Stroke 4.185" bore 6.000" Rods
1. Stock GM Steel Crank .010 .010
2. Keith Black Hyperutetic 12.1:1 Pistons +.60 over bore, block was sonic tested for adequate thickness
3. Scat Pro Comp I Beam Rods, 7/16 ARP Rod Bolts
4. Total Seal Piston Rings
5. Clevite 77 Main and Rod Bearings
6. 400 Main Spacers
7. ARP Main Bolts
8. Dura Bond Cam Bearings
9. Pioneer Brass Freeze Plugs
10. Goodson Deck Plug Kit
11. Fel-pro Rear Main Seal
E-mail [email protected]
Toll Free 800-341-1528
We have over 5000 different combinations, Call us with your entire short block, long block or complete engine needs. 800-341-1528