1972 340 Block vs 1970 340 Block

[soccernut43]

Are there any differences between the 70 block and the 72 block?  Original 70 block was damaged beyond repair and have a 72 block but all 70 parts.  The 70 block was punched out .30 over.  Looking to restore as a cruiser.  Thanks!!

[1 Wild R/T]

Only difference is the date...

[70chall440]

Only difference is the date...

  Most of the time people defer to older engines as being better in construction but in this instance I do not believe this to be the case.

[1 Wild R/T]

Most of the time people defer to older engines as being better in construction but in this instance I do not believe this to be the case.

It's just the block... A 70 has a better crank (forged vs cast) higher compression (10.2 vs 8.5) bigger valves (2.02 vs 1.94)... But the question was about the block..

[soccernut43]

Thanks guys!  Yes, the only concern I may have is with the bore.  The pistons I want to use are from the 70 block that was bored 30 over.  I have to check and see if t his is possible with the 72 block and it's smaller bore.  I think I have 3 cranks, one is steel for sure.  I have a  set of Hamburger heads I purchased 30 some years ago that have never been on a car that I'd like to try and use.  Work in progress.

[1 Wild R/T]

Bore the block no biggie

[Aussie Challenger]

Thanks guys!  Yes, the only concern I may have is with the bore.  The pistons I want to use are from the 70 block that was bored 30 over.  I have to check and see if t his is possible with the 72 block and it's smaller bore.

The 340's all had the same bore size standard before boring, are you sure that your '72 is a 340?

[Locomotion]

It's just the block... A 70 has a better crank (forged vs cast) higher compression (10.2 vs 8.5) bigger valves (2.02 vs 1.94)... But the question was about the block..

(2.02 vs 1.94)

(2.02 vs 1.88)

If just swapping the original rotating assembly into the '72 block, keep it all together. Don't swap any cranks or rods around without rechecking the balance.

[1 Wild R/T]

(2.02 vs 1.94)

(2.02 vs 1.88)

If just swapping the original rotating assembly into the '72 block, keep it all together. Don't swap any cranks or rods around without rechecking the balance.

Missed it by that much.....

[jimynick]

Missed it by that much.....

You just had a wee Chevy moment, that's all. 

[1 Wild R/T]

Only 340's I've ever owned all have had 2.02 valves.... Been around Chevy guys my whole life.. Never owned one... Rarely driven one.... Lots of Fords, no Chevies... Worked on/for Ford for many years, It's how I paid for Mopar's in my early years...

[Locomotion]

Only 340's I've ever owned all have had 2.02 valves.... Been around Chevy guys my whole life.. Never owned one... Rarely driven one.... Lots of Fords, no Chevies... Worked on/for Ford for many years, It's how I paid for Mopar's in my early years...

Well........OK, we'll let it go this time. I'll put this away.

[1 Wild R/T]

https://www.youtube.com/watch?v=qdFLPn30dvQ