[steve25]

What do you have for rear gear ratio?

Note that in the high comp era that factory cams with durations like that your Looking at with that Crower where not used with less then 10.5 to 1 true compression and with a minimum of 3.90’rear gears.

Keep in mind that it’s far better to be under Cam’ed then over Cam’ed in terms of average street performance as long as the amount of cylinder pressure does not make for ping or knock conditions.

The average 68 to 70 400 motor rated at 350 hp had a true 9.5 compression and used the factory 067 Cam which had 197/212 @ ,050” with only .407” lift, and on top of that exhaled thru log type manifolds.

If you want to run that Crower cam with a compression ratio that will work with 91 octane and not have a car that’s a Dog below 3500 rpm then you want to run Rhoads lifters to off set that!

To end up with your goal of a 9.3 compression with your 406 cid motor you will need a total of 100 CCs when your piston is at TDC.

75 CCs of chamber volume plus a 14 cc dish gets you to 89 CCs.
Now add 9.4 CCs for a Fel Pro 1016 head gasket and your at 98.4 CCs.

Add another 4. 43 CCs of a deck clearance of .020” and your at a total of 102.8CCs.

Now lastly add in 1.2 CCs for compression ring land volume and your at 103.8 CCs total.

Looks like your 3.8 CCs over where you need to be if your heads do CC out to 75.

To get to your dead on target compression of 9.3 you will need to mill the heads .022 or get pistons made with only a dish of 10.2 CCs.