Recently cc'd my original LT1 heads . Thought I should share that here. After 8 tries on 2 different cylinders I got average of 54.5cc's. Maybe 55cc's could be closer but I dont know how some builders get it to the 10th of a cc.

I'll to attach the pix. If this doesn't work I'll come back with a link.

 

So moved on to measure volume above the #1 piston at TDC but the alcohol wouldn't flow all the way across the top of piston. So I have to regroup and get the dial indicator back out and move the piston down the hole some amount. Sorry no pics as my hands had to much grease on them to touch the camera.

I want to do this before pulling the pistons for a reference for others here swapping head gaskets and such. Using a feeler gauge I saw 0.019" on the center top of piston to the flat plexiglass at TDC. I was expecting 0.025".

Hope to try again soon.

 

Okay I gave the above piston volume another try. Use rotating the piston 0.025" down the hole. BTW that measured 'bout 12 degrees of crank rotation. Gave me 'bout 17cc of volume after subtracting the 0.025" volume. I did have a slow leak though and couldn't seem to get the last bubble to fill but 17cc should be very close and I will try again with a different grease when possible. That 17cc includes the valve reliefs in the piston which by themselves are somewhere between 2cc and 3cc for all four reliefs.

Anyways using a 4.125"x0.040" head gasket this adds up to a true static compression ratio of 9.87:1 or 9.9:1 for you expeditious types. But again I did have slow leakage which would increase the static volume and reduce over compression ratio estimates. I plan to try again though maybe using the piston 0.050" down the bore.

Hope you can enjoy the pix.

 

Ok gave it another try but small bubbles still a problem. I could get close by moving the piston further down but small bubbles were too stubborn and moving the plexiglass to vent them just made them worse. Tried it with piston 0.050" down the hole - in first pix and got c.r. = 10.5 (10.496266). This had measured 11.703cc liquid volume above the piston.
Then tried it with piston 0.100" down and got c.r. = 10.6 (10.59752). Note how much smaller the bubble is in pic #2. That measured 10.907cc liquid volume above the piston.

Maybe what carbon build-up was left on the piston or I used to much grease in the piston cyl wall crevice but I'm gonna call stock LT1 c.r. = 10.5. At least for 1994 anyways.

Couple of notes is the piston is 12 degrees ATDC when 0.050" down and 17 degrees ATDC when 0.100" down.

Enough of stock specs but it was good practice for measuring during assembly. I can get the tools out and measure in less than an hour now.

Finally now i can move on to engine disassembly.

 

Next step is to pull the pistons and measure the "eyebrows/piston reliefs". How much of a press do I need to press the pistons off the rods. Manual Arbor press or 12 ton hydraulic?

Anyone know?