While waiting for the machine shop, I'm playing with cam timing and piston specs - trying to get an idea of what happens with various combinations and the resulting drivability and potential detonation tradeoffs. Here's a calculator for estimating dynamic CR with variable cam specs:

web page

I used the following input data:

bore = 3.587"
stroke = 2.992"
rod length = 5.625" (rough measurement with rule)
static compression ratio =
- 8.9 w/Montero pistons
- 10.0 w/Diamante pistons
inlet valve closes ABDC =
- 59* w/Montero cams
- 66* w/Diamante cams
boost pressure = 7 psi
target altitude = 0 (sea level)

Dynamic CR results at 0/7 psi:

7.36/10.86 = 8.9 pistons w/Montero cams
6.99/10.32 = 8.9 pistons w/Diamante cams
8.25/12.18 = 10.0 pistons w/Montero cams
7.83/11.56 = 10.0 pistons w/Diamante cams

I've read that good N/A street engines have a dynamic CR of 7.5-8.5 and wondering if the later-closing Diamante cams used with the 8.9 pistons will make the engine a dog when not under boost.......

So, I tried using the DOHC specs for turbo (8:1/55*ABDC) and non-turbo (10:1/55*ABDC) and got these results:

6.83/10.08 = turbo
8.49/12.53 = non-turbo

Obviously, I'm not going to use the 10:1 pistons with a blower unless I was also using a racing cam and needed to get the dynamic CR up to where it all worked together, but it's interesting to find the turbo DOHC engine at 6.83:1 dynamic CR - but I suppose the M/T allows the engine to get into the torque range before launch.

The combination of Diamante cams and 8.9 pistons seems to give a measure of detonation protection under boost compared to the Montero cams - if the tradeoff isn't too bad with no boost.

This is all theoretical and conjectural "what-ifs" on my part...... opinions/corrections welcomed.

Frank