Cam timing - SBC

[MIJeepBoy]

How do I know that when I put a 350 together the cam won't be 180* off? Is it a slim chance that would happen or is it a 50/50 chance?

[chevyman_400]

Look at the timing mark on the cam gear and the crank if they are both up and #1 is at top dead center then you are fine

[MIJeepBoy]

Is that all? I have heard the cam could be on the wrong stroke and try to fire on the exhaust stroke or something, but is it just line the marks up?

[gottagofast]

thats right ....... also if you have the timing cover on you can tell by watching the rockers on number one an you turn the motor by hand if one is closing and the other is begining to open when the piston reaches the top and the timing mark is lining up on the balancer you will be at tdc on the exhaust stroke for number one and firing position for number 6 so the rotor should point away from number one (180 0ut) ...... if both valves are closed as number one piston is nearing the top of the cylinder and timing marks are lining up the engine tdc on the compression stroke and at the firing pos for number one and the rotor should point towards number one

MIJeepboy,
Don't worry about getting the cam 180 deg off, it can't be done. Line up the marks. Then turn the crank one turn, you'll see that the cam has only turned 180 deg. So if you lined up the marks with the cam 180 deg off, it would be perfectly aligned when you turned the crank one turn. The cam DETERMINES whether the cylinder is on compression or exhaust when the piston is rising, the piston itself doesn't care.
Then follow gottagofast's instructions for distributor timing, and you'll be running in no time.
Pete

[RRich]

Something interesting that most folks don't know.
When the cam gear's mark is at the bottom and the crank's mark
is at the top and lined up (marks are next to each other ) -
it's not on the compression stroke, it's on the backside.

Compression stroke is when the cam gear's mark is at the top
- then you can drop the distributor in and point it to #1.

Else you'll get the dist 180 out.