Hey guys finally found a car I'm thinking about buy. Going to look at it tomorrow evening, However the car has been sitting for about 10 years. I want to crank the engine over by hand just to make sure the engine isn't seized need to know what size wrench to take. Its a 71 240

Thanks all

The crank pulley bolt has a 27mm head.

Thanks thats what I needed to know. Wish me luck.

You could also put it in high gear and roll it by grabbing a tire and turning it. An alternative if it's a manual.

Remove the spark plugs and poor some penetrating type oil in each cylinder before trying too hard to turn the engine over. If the rings are rusted to the bores you could break the rings. Have a look into the oil filler hole to check for rust on the cam lobes that you can see there. A torch would help.If the cam is rusty, I would not turn it over. Engine work is the easy bit. Number one --Body rust. Good luck.

Brian.