340 compression ratio

I am trying to figure out my compression ratio on this dart i got a few years ago. i bought it from a guy that built it for racing. Can i figure this out without taking apart the engine?

So the things i need to know to find the compression ratio are:
Bore
Stroke
Clearance Volume
Swept Volume

Compression Ratio is swept volume plus clearance volume divided by clearance volume.

On a stock 340 the bore is 4.04 and the stroke is 3.31

So unless he bored the engine to a bigger size, the bore should be 4.04.

The stroke i tried to manually measure the piston #1 travel from TDC to BDC with a plastic pencil rod (through the spark plug hole) and i came up with about 3.5 (which is not very exact). so I'm not exactly sure what the stroke is.

I can find swept volume if i have the correct bore and stroke (i think you can also take 340 CI and divide it by 8 cylinders)

Clearance volume is the combustion area of the head? i was able to look up that head number and i found these numbers for combustion chamber volume 65.0 - 73.0. This gives me a range which is not exact…and is that CI? per cylinder? Where do i find the exact volume?


Here are my numbers and information that i have:

Car Vin: LH2360R202155

Block Casting #: 2780930-340-7

Right Head Casting #'s (i had to take the valve cover off to find them inside):
03671587 1 0823 123 360 AAWJ

Left:
3671587-12 0783 123 360 AAWJ

I found one place that said these heads would have 2.02 intake and 1.60 exhaust and another place that said 1.88 intake and 1.60 exhaust

Intake Manifold: 340 Victor

Carb: Holly 800 Double Pumper

Camshaft: (i don't know what these numbers mean, he had them written down in some of his notes)
High Flow IH
#420421
.470 Lift
298 Duration
229 @ .50
IO 44 IC77
EO 77 EC 41

Transmission left side:
3410452-2

I also need to find a dust cover for the transmission, to keep dirt out of the ring gear, starter area.

I ordered a new summit racing pro torque starter, because i wore out the factory starter by cranking so much trying to get it to start so i could tune the carb.

I also need to get a good carb kit and a good book for that holly 800. something that comes with all new gaskets, and jets and all that good stuff. i have so much black soot build up on this one because i was running too low of a octane on fuel.

Also, what do you recommend for racing engine oil for this motor. I think he said he was running Kendal 50 weight.

This is a lot of questions, but i really appreciate all the input. I need all the help i can get, i am learning….i would like to be a expert of this stuff, but am so limited on time because i work so much.

Thanks…

Steve :prayer: