318 v 340 Crankshaft

72DartSwingerV8 said

Alright, so the most cost effective way to do this would be getting a forged 318 crank and have some metal removed, balanced, with aluminum pistons and all that stuff. It would be cool to get a 340 crank but I really don't like the idea of metal added and the cost of that will obviously be a lot more. AM I missing anything?

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I don't know about that, the 318 crank is the lighter crank. I would have the 318 pistons weighed and then check around for aftermarket pistons, most manufactures have the weight advertised with the piston so you wouldn't need to buy any till you know for sure.

It would definitely be easier to find a good 318 cast crank than a good 340 crank but the forged 318 cranks aren't as easy to find as a cast 318 It would be cheaper as long as you get aftermarket pistons that are lighter than the stock 318 pistons. I personally would stay away from the cast 340 cranks.

With all things considered though, if all you have is a block, the cheapest may be to buy a stroker kit since any used crank will need machine work as well as the rods. some of the stroker kits come complete and balanced ready for use. The reason a lot of people use to use the 318 cranks in 340's is because there were really no options for aftermarket cranks 20+ years ago and it was the only option to build a 340 if all you had was the block or one with a bad crank.

The best advice would be to shop around and get the prices from machine shops on the machine work needed with an old crank and the prices from aftermarket companies on the parts you need to use the 318 crank, 340 crank or a stroker kit and make your decision based on what you find.