340 crank in 318?

340 cranks are balanced for those heavy OEM pistons. will it fit ? Yeah. Will you be able to balance it? Break out your wallet.
-The early 318(pre 69 IIRC) were steel. Those 318 pistons were way lighter.
-I have a 1965 273 crank. Pretty sure its steel. The 273 rods are kinda puny though. So again might not be the cheapest to balance.
-Im running a stock 1971 360 cast crank in my 68 Formula S clone. Been revving it to 7000+ for 15 years/120,000 miles.Almost no racing(maybe a dozen passes).Maybe Im just lucky.Im not scared of cast cranks on a streeter. Maybe I should be.IDK.
-Should probably mention though; cast cranks are not what you want to support 800hp.
Also, at that hp level, its going to get real pricey on a 318.You might as well start with a 360 and a stroker kit.Otherwise youre gonna have to run some serious boost. Serious boost breaks stuff. It sounds to me like youre about to bite off more than you can chew.Am I wrong?