CNC-Motorsports Chevy 415-421 short blocks have quickly raised the bar to a new level in offering high quality performance short blocks at an affordable price. CNC dart short blocks have become a huge hit among racers and performance enthusiast all over the world. We have the ability to custom build you just about any combination the way you want it. All our short blocks are 100% machined, CNC Machined and blue-printed to our race wining specs. We will never cut corners just to lessen the price. Please contact us if you’re looking for something not listed and we will be more than happy to give you a quote..