Dan Leadbetters 496ci...
Dan Leadbetters 496ci Rat uses oval-port Edelbrock aluminum heads and a torque-enhancing camshaft to move his 3640 pound 66 Chevelle down the quarter-mile in 10.70 seconds at 125 mph.
No matter how fat the Rat, if it doesnt contain the correct pieces it wont run as strong as the next guys effort. General Motors built three generations of big-block engines with combinations that included everything from mild-mannered hydraulic camshafts and oval-port cylinder heads to monster mechanical flat-tappet camshafts with rectangular-port cylinder heads.
Numerous private engine shops now offer crate engine packages of more than 600 inches and 700 normally aspirated horsepower. GM Performance Parts offers a 454 H.O. capable of making over 500 lb-ft of torque at 3,250 rpm, while the larger ZZ502 punches out 567 lb-ft of torque at 4,200 rpm. No matter what big-block combination you call your own, the power relies on the pieces you choose to develop that curve. We have assembled the following list of our favorite big-block parts to provide guidelines to help you make your large-inch engine be all it can be.