E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: Rich G. on April 01, 2025, 06:25:50 AM

Title: 340 engine
Post by: Rich G. on April 01, 2025, 06:25:50 AM
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.
Title: Re: 340 engine
Post by: 340sport on April 01, 2025, 09:23:43 AM
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.
Title: Re: 340 engine
Post by: Rich G. on April 01, 2025, 12:28:35 PM
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.
Title: Re: 340 engine
Post by: Brads70 on April 01, 2025, 01:16:28 PM
Can you post a picture of the crank flange?
Title: Re: 340 engine
Post by: jimynick on April 01, 2025, 05:45:08 PM
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.  :bigthumb:
Title: Re: 340 engine
Post by: EV2RTSE on April 02, 2025, 02:40:33 AM
Earlier 340s were all forged crank, I think it is generally accepted that they switched to cast cranks around April of 1972. :cheers:
Title: Re: 340 engine
Post by: HP2 on April 02, 2025, 03:34:59 PM
With a born-on date of '68 and what looks like the thin balancer on the front, it would be a forged crank.