Updated Nov 19, 2008

With the latest cam swap to the Comp Cams xe256 cam, Desktop Dyno says my 383 makes about 375 horsepower and 440 foot pounds of torque. I've always thought their numbers were a little generous though. Anyhow, for the curious, here are the specs that I plugged into Desktop Dyno 2000 to generate this chart:

• 383 CID

• AFR 190 head flow file (see below for more on head and cam files)

• Camshaft: 212/218 @ .050" .479"/.486 lift (using 1.6 rockers)

• 800 cfm carburetor

• Small tube headers with muffler exhaust

This is the chart for the last configuration of my 383, same as above except using a Comp Cams xe274 cam:

• 383 CID

• AFR 190 head flow file (see below for more on head and cam files)

• Camshaft: 230/236 @ .050" .487"/.490 lift

• 800 cfm carburetor

• Small tube headers with muffler exhaust

Here's a chart for the old 408. Around 440 foot pounds of torque and 420 horsepower. Here are the specs that I plugged into Desktop Dyno 2000 to generate this chart, it's the same specs as the 383 with the xe274 cam, except for 408 CID:

• 408 CID

• AFR 190 head flow file (see below for more on head and cam files)

• Camshaft: 230/236 @ .050" .487"/.490 lift

• 800 cfm carburetor

• Small tube headers with muffler exhaust

Attention Desktop Dyno 2000 users: A fellow Chevrolet enthusiast has compiled a large number of camshaft, head flow, and engine template files, and has posted them on his website. If you go there, make sure to check out the rest of his site too. There is a ton of great information there.

Here's a link to The Unofficial Dyno2000 file page

And to his main page: Ray and Gayle Buck's Chevy Asylum

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