Vitos Big bore kit

No no, You said you've seen beer boxes hold up against water pump and thermostat housings. Most radiator coolant loops run ~ 13 psi of pressure so a homemade gasket would have to stand upto that pressure. BUT, it wouldn't have to stand up to bunches of pressure (in the form of the piston coming down to force the charge up the transfer) and then bunches of vacuum (the piston going up sucking new charge into the engine particularly when the carburetor slide is closed).

That'll suck a paper gasket into the transfer, ask AWK. He was sent into the machine shop to bore out a cylinder when his "riding style" combined with a paper base gasket to ruin a perfectly good piston. Not that it wasn't a good learning experience and he happened to be in the perfect place to do it anyway...