340 engine

[Rich G.]

I have this 340 engine laying around. How do I determine what flywheel or torque converter I would need if I want to use it.

[340sport]

What year is the 340? If completely stock, that will tell you if it has a cast or steel crank, unless you already know how to tell.
To me, it looks like a steel crank balancer. If so, you need just a regular 'X' shaped flex plate to bolt to the torque convertor if an automatic.
If a cast crank, it will have a weighted balancer and you will need a weighted torque convertor or weighted flex plate and a neutral balanced convertor.

[Rich G.]

Thanks for the reply, I believe it's a 68 or 69 engine. I really don't know how to tell if it's a steel or cast crank. I know it will vibrate with the wrong one in.

[Brads70]

Can you post a picture of the crank flange?

[jimynick]

Born in '68? I'll make a modest wager that it's a steel crank. If it were a cast crank, the balancer would show the offset weight. 68's were stout and had 10.5:1 CR and often X casting heads; all good stuff. Barring some horrendous internal issue, she's a keeper. 

[EV2RTSE]

Earlier 340s were all forged crank, I think it is generally accepted that they switched to cast cranks around April of 1972.

[HP2]

With a born-on date of '68 and what looks like the thin balancer on the front, it would be a forged crank.