What's my compression Ratio?

I have a '74 block with .030 over dished pistons.

The heads are '66.

Other than the overbore, I think everything is stock.

I think dished pistons were normal for '74, but with the combustion chamber of the '66 heads, I maybe down around 8:1 or lower.

The lady I got the car from got it in the late 70's and whoever did the engine work was before that, 'cause she said it never had been apart.

I checked compression a while back and got 125-135psi

When I took it apart to put new gaskets and seals, I could still see the crosshatch pattern on the bores.

What do you engine gurus think?

Thanks, I actually thought it'd be lower.

Do you know what the chamber size is on '66 289 heads?

Thanks!