Peter, that cam is really "small" for the cid and static compression ratio. It should make plenty of vacuum and be computer friendly. With only 256/262 degrees of off seat valve timing, and a 110LSA, it isn't going to make a lot of power in the upper rpm range, even with better flowing heads. Still a decent choice for the application, being both user and ECM friendly.
As mentioned above, the only real function of the ECM is part throttle A/F, so anything done to improve the A/F ratio in that area will help with efficiency, which translates into smooth for normal driving and less fuel consumption.
The idle and full throttle systems are pretty much the same as the older q-jets. This lets us install slightly larger cams and still bring in enough idle fuel and bypass air to keep the vacuum high enough to make the computer happy. At WOT we can quickly change the total A/F ratio by using different secondary metering rods, and hanger height.
I'm not sure what cylinder head castings they used in 1981 on those engines. The very best SBC factory castings (large chamber) were produced until 1973-74, castings 441, 487, 993, 336. There are a few others but they are not as common. The 041 and 186 castings were excellent small chamber offerings. I didn't list the earlier casting numbers due to lacking the accessory bolt holes.
* Just a side note here, as good as some of the factory castings were, they are "thin" in comparison to most aftermarket offerings, and woln't flow nearly as well. Most have 165/65cc runners. The aftermarket has stepped up so well with aftermarket offerings, with low pricing, that it makes little sense these days to use old worn out factory castings, most of which are cracked someplace. GM also offers "Vortec" heads, very reasonable. However, we don't consider them a big bargain, as they are relatively "thin", and could use some upgrading to the studs, springs, retainers and valves. By the time you get them up to par, a set of Iron Eagle or World Products heads could have been had for about the same money.
In 1974 the 882 castings came out, and a couple other really poor flowing designs. They ran these heads on nearly every 350 and 400 that came down the assembly line to at least 1979, maybe even into the 1980's. They are very restictive, and prompted cam manufactures to start pushing dual pattern camshafts with more exhaust than intake duration, and tighter LSA's (Lobe Separation Angles).
I've never to date been overly impressed with any of those camshafts when used with good flowing cylinder heads. All one has to do is to get some good cylinder heads, locate an "obsolete" 327/350 hp camshaft (224/224/114), and the power improvement will be amazing. Yes, even the vast majority of the GM "high performance" grinds are on wide LSA's, and the run high static compression ratios with them as well.
Despite how well the factory parts work, aftermarket companies still push the tight LSA stuff with less seat timing, faster ramps and more advertised duration. They advertise improved idle, improved throttle response, stronger mid-range and more top end power, even though their cams will have 20-30 degrees LESS off seat valve movements and quite a bit LESS overlap. Makes one wonder how we can do "more with less"??
My testing doesn't show this to be true, as we've installed and tested a few aftermarket "high" performance flat cams with the "modern" lobe designs, and LOST power every single time just about everyplace!
Anyhow, I'll get back to carb stuff, as that's what this Forum is about.........Cliff
