[Cliff R]

A reality check is in order here. IF you cam one of these late model low compression 400's with enough duration to pull HARD to and past 5000rpms you are going to have to drop it off a floor jack to spin the tires from a stoplight! Compression is your friend with these things, and your enemy. Unless you have 6X-4 heads that have been milled down a bit, flat top two valve relief pistons close to zero deck, and a thin head gasket to get the squish tight and compression up to at least 9 to 1 looking at cams with enough duration to make strong upper mid-range and top end power is a complete waste of time.

The 4 speed and 3.23's help some here but it doesn't appear we're going to have much past 8 to 1 compression when it's all said and done. It also appears that idle sound is on the list of requirements. You just can't have your cake and eat it to with a 400 build at 8 to 1 compression pushing around a car weighing 2 tons. Big cams with a lot of overlap are not on the list with these builds.

I have typically avoided "low" compression 400 builds over the years as most customers I've had were wanting a stroked version or going to early heads to get the compression up some. They already knew those engines were turds right out of the box and had owned the cars long enough to want to up the power considerably. The few that I got involved with early on educated me to stay away from larger cams in them. One was brought here to custom tune that had the Summit 2801 cam in it. It was really "soft" off idle and didn't start pulling well till 3000rpms or so. Had another in here with a Comp XE262 cam in it, what a gutless turd that was. Even got involved with one that supposedly had the compression raised some and Comp XE268 cam, it was even a bigger turd! I've also been around a few with the Summit 2800 cam in them and they were remarkably smooth at idle compared to the Crower cam. That would be a close second choice for one of these engines if I were building it here and the customer wanted stock type idle and good street manners.

I'm mentioned several times on here over the years that the first engine in my Ventura had 6X heads on it and the Crower 60240 cam, 210/221/112 LSA. Idle quality was decent, just a hint of a larger cam going on in the idle note. Strong mid range power and pulled really hard to 5000rpm's, and excellent street manners.. With 2.73 gears, TH400, and a stock converter it ran 14.0's @ 99-100mph at the track on BFG street tires. Best run ever in really good air and track conditions was 13.87 @ 101mph. That's getting it done pretty good for a pretty much stock late model 400 build with unported 6X heads on it......