72 steel or cast crank?

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titanium

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A gentleman in my area has a 72 340 for sale. It is a 72 340 with J heads that have the 2.02 valves in them. The date on the block is 5-29-72. My question is would this 340 have a steel or cast crank. I thought I had read somewhere that late 72 340's switched to cast.
Thanks
 
I believe some '72 escaped the factory with forged cranks but for the most part '72 are cast,you can usually tell by looking at the damper...
 
Look to see if the balancer is externally balanced, if so it's a cast crank. Should also say use with 340 cast crank only. Just pull the pan to make sure.
 
Late 72 used what was available on the production line.
Best guess is 5-29-72 date, by the time the block was machined is a cast crank.
 
sireland67 said:
Late 72 used what was available on the production line.
Best guess is 5-29-72 date, by the time the block was machined is a cast crank.
Click to expand...

Late 1972 would ba a 1973 model year as the new models used to come out in September. If a 1972 model car with a 340 has a cast crank, it's the wrong one.
 
O.K. guys thanks for the info. I'm hoping it is forged. He says it is forged but not sure.I will give him a call back. It is a rebuilt motor with 10.5 pistons. Whats something like this worth?
Thanks again
 
the cast crank was original equipment in 1972.
the date of integration, i don't know...


according to the cronology at allpar-- 340's had 1.88 exhaust valves..
340's NEVER has 1.88 exhaust valves.
..not all the information written is correct
 
1972 - The 340 four-barrel dropped to 240 horsepower:
◦Compression dropped to 8.5:1; the compression height of the piston via wrist pin location changed by 0.10”
◦The crankshaft was switched from forged to cast somewhere in the production cycle, believed to be in early April 1972; a milder camshaft was used
From Allpar.com
 
Well - all those different replies certainly made it clear as mud............just saying.....:study: :grin:
I was too lazy to check my build dates, but my my '72 TB3 Duster 4 speed, and my Red '72 3 speed both have steel cranks in them.
It could be anything in there for a crank, because if the comprssion ratio is 10.5:1, then that is definitley not stock for '72...........so I would not get too hung up on the date - just verify what you can see with your own eyes or on paper.
Daryl
 
Good Lord yall. In the end, who gives a ****? Just make sure whichever crank you have has the correct corresponding balancer.
 
titanium said:
A gentleman in my area has a 72 340 for sale. It is a 72 340 with J heads that have the 2.02 valves in them. The date on the block is 5-29-72. My question is would this 340 have a steel or cast crank. I thought I had read somewhere that late 72 340's switched to cast.
Thanks
Click to expand...

That year engine did not come from the factory with 2.02...they were 1.88......
 
No the cams were the same. Only two camshafts where used on the 340 since it's intro in '68. In '68 the 4 speed cars did have a different cam grind than the auto..'69 and on, ALL 340's used the '68 auto camshaft. The '72 340's had the '360' intake valves and 8.5 CR from the lowering of the piston .100 in the bore. The '72 and the '73 340 used the very good TQ and the TQ manifold from the '71 340. Compression ratio and the intake valves were the changes from '71 to '72..and the cast crank later in the '72 model year same for the '73. My '72 Duster 340 does indeed have the forged crankshaft. JMHO..I believe the '71 340 to be THE best year for the 'mighty lightweight' ! still had the forged crank, still had the compression , still had the big valves and the TQ carb and manifold which was superior to the AFB carb/manifold. I believe it to be about 10 horse better than the '70 six-pac 340's. NHRA agreed with me,.. when they refactored the '71 340 to 330 horse. IIRC, the '68 and '70 340 was NHRA factored to 310 and the six-pac 340 to 320 horse. The '72 340 was SAE rated at 240 horse but that was a different rating system than the earlier engines received. The '72-'73's would be in the 270-275 horse range if rated at the crank. For the '68-'71 the 275 horse rating was a JOKE...We all know that Mother Mopar did infact 'underate' the '68 - '71 340 at 275. So did the NHRA..and the Insurance company's. LOL.
 
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