Welcome to CHR!

We’re a pretty friendly bunch and love to hear about all kinds of racing – straight line or “go-round-and-round”.

As you may already know, the Vortec L31 engine is a 350 truck engine. It’s 5.7 liter displacement is why it is sometimes referred to as the “5700”. It was used in every Chevy/GMC/Cadillac truck platform from 1996 to 2000 and box vans from '96 to '03 (including the Isuzu cab forward popular with plumbers and electricians). There’s a zillion of these engines out there (would be more if the “cash-for-clunkers” hadn’t happened, but that’s another story!!)

In its stock form with the Vortec heads it had a 9.1:1 compression ratio and was a great un-leaded regular engine. Stock horsepower was 220-255 during its lifetime. Torque was consistently 330ft/lb. Stock cam specs were .414/428 lift and .191/.196 duration on all production L31 engines. 2002 was the final year for the L31 and the end of the “traditional small block” with its interchangeable components that dated back to 1955.

The Vortec heads are based off the second-generation of LT engines with 1.94/.150 valves a 64cc combustion chamber of. These were fantastic heads (many believe the best production cast iron heads to come out of GM) and can support over 400 horsepower and pull strong to 6000RPM out of the box.

If there is a drawback to stock Vortec heads, it’s their limited lift capabilities. The stock Vortec heads are good to .450 lift. I know of instances where people have claimed +/-.470, but I would be concerned with coil bind on anything higher than .450 lift. Your rules prohibit roller cams and rockers on carbureted engines, so your options need to focus on flat tappet. Howards makes a cam that would allow you to maximize the stock Vortec heads with .450 lift on intake and exhaust and 267 degrees of advertised duration (213/213 @ .050 lift). Summit part number: http://www.summitracing.com/parts/hr...make/chevrolet with lifters for $166 so it’s well within your low-budget concerns.

Also appears that your rules mandate stock exhaust with offset mufflers (no straight through) and no headers. Keeps the noise down for sure!!

Good Luck,
Glenn