Need information 70 340 block a cast crank?

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SMCARNUT

SMCARNUT

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I just picked up a 340 long block. The block is cast in 1970 see picture. I think the crank rods and pistons must have been swapped out. The engine has a cast crank balancer. I road in the car a number of years back no engine vibration. The motor ran well.
Can someone run the engine numbers and let me know what it came out of?
I am planning to use the motor in my 71 Demon. If someone has the car this block belongs to I would rather they have the chance to buy it before I get too far into this project.
I will start taking the motor apart in the near future.

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I don't think it's a 340 cast crank balancer- it would have the "use with 340 cast crank only" disclaimer cast into the balancer.
OIP.eKayQIRCTx2gW1PM7WoedAHaDg?w=320&h=165&c=7&r=0&o=5&dpr=1.1&pid=1.jpg
OIP.E0kEQcz-Y_Y2_pZK8pm80QHaFj?w=288&h=216&c=7&r=0&o=5&dpr=1.1&pid=1.jpg


That actually looks like someone used a 440 Six Pack balancer (which was also used on many 4 bbl. 440s too, if they had the heavy rods) on it...
OIP.CCmsDbU4ivzADzEl3HN9xQAAAA?w=196&h=159&c=7&r=0&o=5&dpr=1.1&pid=1.jpg

Might have been done during a previous build to help offset a heavier set of pistons?
 
SMCARNUT said:
View attachment 1715947050
Click to expand...


That's definitely an early 360 balancer before they started casting it with weight out of the opposite side.

I wonder if a 360 crank was cut to 340 specs or the balancer was used to help balance a 340 rotating assemble. Got the balancer or flywheel from that engine?
This ought to be interesting.
 
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Yeah, the 2 different 360 balancers I've seen are like this:
upload_2022-6-25_17-12-21.jpeg
upload_2022-6-25_17-12-42.jpeg

Could it have been put together with a stroker rotating assembly? Definitely pay close attention to the crank when you tear it down...
 
My friend bought a car with this engine in it and all we knew that it was a 340 engine no details and no specs on the motor. The motor ran good did not leak any oil and did not overheat etc. He decided to put a 408 stroker in it that is how I ended up with this motor.
 
The balancer looks exactly like the one on the right. I will tear into the motor next weekend.
 
The engine was cast in Feb. of 1970
The engine went into a 1971 car
It came out of the factory with a steel crank and a neutral harmonic balancer.
There are more numbers on the front of the block under the driver's side cyl. head.
 
Only one way to know. Get it apart.
 
oldkimmer said:
Looks like a 400 damper to me. Kim
Click to expand...

A big block balancer wouldn't work at all. It would fit on the crank, but it would bind on the timing cover where the timing marks are because the BB balancer snout is shorter than on a SB.
 
Motor has a 360 balancer. The motor has .030 TRW / Sealed Power L2316 pistons. Crank is a cast iron. Has J Heads that have 360 cast into them with 2.02 valves.
Looks to be a Frankenstein 340 motor lots of different parts used to make one motor. At least I know now thanks for everyone's help and input.
 
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