I just finished dyno testing a 81 L81 with an automatic this morning. I wanted to post up the dyno sheet and list of mods so anyone considering these mods can see how they will improve your power. The car was bone stock when in came in. Here is a list of the mods:

Comp Cams 268H kit with springs, cam, and timing chain
Summit 1.5 full roller rockers
Holley Street Advenger 670 cfm vacuum secondaries
Summit Stage One Dual Plane Manifold
Summit HEI Universal distibuter with Vac advance
Flowtech Headers
2 1/2 dual into a 3" cat into 2 1/2 dual dyno max race mufflers

Best a/f ratio was with 67 primary jets and 70 secondary jets

Best timing was 35.5 full mechanical advance

Stock rwhp 135 @ 3600 - Modified rwhp 200 @ 4300
Stock rwtrq 213 @ 3050 - Modified rwtrq 267 @ 3400




The 268H cam does a nice job moving and making the power where you can use it. Chevy should almost be embarrassed by what they offered in these cars for horsepower stock.

I thought I would share this with everyone here since I see the 268H is a popular cam choice. It is definately worth doing on a stock engine if you have alread done the bolt ons. Flywheel power calculates out to about 281 horsepower and 376 torque. Should be a nice driver.

 

... with stock heads?

And wow, that stock torque curve is pretty fantastic.

 

Yep, stock heads with just the valve springs upgraded.