decode this 340

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ir3333

ir3333

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Looking at a '69 Dart,340 4 speed....
Front of block....HM340-3958144 (as near as i can tell)
Below drivers' side manifold 2780930-340-2.
H .... 1972?
Hamtramck?
 
Could be a rebuilder's number. Check the casting date on the block side. That'll tell you what year the block is, at least.
 
ir3333 said:
Looking at a '69 Dart,340 4 speed....
Front of block....HM340-3958144 (as near as i can tell)
Below drivers' side manifold 2780930-340-2.
H .... 1972?
Hamtramck?
Click to expand...

Best i can tell by research, the H code is 1972. The numbers after the HM340 are usually eight digits? But, just saying that is the correct number, the 3958 is May 29, 1972 on the Chrysler calendar. It may be correct, but that happened to be Memorial day that year and i'm not sure the factory was working that day? Member "crackedback" is a wiz at this stuff. Hopefully he'll chime in with his thoughts.
 
H = 1972
M = Marysville engine plant
340-
3958 = Monday, May 29, 1972
144 = 144th engine built that day, might be missing another number.
 
What is the vin # on the block? Pass. Side down by oil pan rail, on a flat machined area there is #s pounched in. Mike.
 
Yes..my bad,one digit out.
HM340-39758144
Where is the Marysville engine plant...just curious?
 
Rocky_JS said:
H = 1972
M = Marysville engine plant
340-
3958 = Monday, May 29, 1972
144 = 144th engine built that day, might be missing another number.
Click to expand...

All pretty much spot on except engine plant. M= Mound Road

3975 = 6/15/1972

Seeing it's 8144 it's the 8144th unit that day.
 
No idea, you'd have to look at the balancer or the parting line on your engine's crankshaft.

Most likely a cast crank.
 
crackedback said:
No idea, you'd have to look at the balancer or the parting line on your engine's crankshaft.

Most likely a cast crank.
Click to expand...

I agree. Although i wasn't sold, seems like most of the numbers cars still around had a cast crank after Apr. 72.
 
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