273 crank into a 340

[Gordon340]

I am considering buying a 340 block, rods & pistons and heads minus the crank. I have a 67 273 with a nice forged crank in it. I realize that this is not as strong as a 340 crank, but does anyone see any problems with this set up if the engine is just as a weekend driver on the street?

Thanks
Brian

 

[Locomotion]

You will have to rebalance the rotating assembly. Also, I don't recall the specific years, but there is a chance that your 273 crank has a smaller register for the converter snout than the newer, more common Mopar converters. If needed, you could have the back of the crank machined to accept the more common converters.

I just don't remember what year they went to the bigger size in the 273 cranks.

 

[rumblefish360]

I also have a void on that info. Good loco remembered it. Otherwise my answer would have looked like this.

The 273-318 and 340 have the same journal sizes. Weather or not the crank is forgded or cast, it will drop in.
MoPars cranks are tuff and will hold lots-o-HP.
All the fordged cranks to my knowleadge are from the same material, so the 273 crank is as tuff as the 340 crank.
Don't let the displacement fool you on how strong it is.

Now go back and re-read Loco's post. <LOL> I do believe they may be a cave eat to watch out for.
(I have a book around here somewhere......)