340 pistons and rods in a 360

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Bigboy 68

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Can I use 340 standard pistons and rods in a 360 engine block my block has to be bored 40 over any help is appreciated thank you
 

I think you’ll find the compression height far too different for this to work unless you had custom rods to make up the difference.
 
The articles I've seen used the TRW low compression pistons with the .300 thick crown milled down to 3/16 thick with a bevel (I think 45 degree?) cut from the top ring land to the crown. It's usually cheaper to buy hypereutectics that already fit if they're available unless you have a small home mill and the skills to do the work to fixture a piston into it.
 
Gentleman I thank you for all the replies my question of can you use 340 pistons in a 360 has been answered I will just look for a set of 360 Pistons thank you very much
 
Can I use 340 standard pistons and rods in a 360 engine block my block has to be bored 40 over any help is appreciated thank you
That answer is yes if the stroke is the same. If you have a 360 main crank but have the stroke of a 340, then yes.
Stick the 340 pistons & rods (all rods the same length!), the extra stroke the 360 has over the 340 (3.58 - 3.31 = .27) leaves the high compression pistons way to high.

The KB mention of the Hyperutecic slugs (KB 107) also have a forged counterpart, FWIW.
Cranks are available with the 360 main and the 3.31 stroke. IDK know if you have a machinist that would know or can regrind the crank. Which is not a bad option and relatively inexpensive.

Good luck with the build.
 
That answer is yes if the stroke is the same. If you have a 360 main crank but have the stroke of a 340, then yes.
Stick the 340 pistons & rods (all rods the same length!), the extra stroke the 360 has over the 340 (3.58 - 3.31 = .27) leaves the high compression pistons way to high.

The KB mention of the Hyperutecic slugs (KB 107) also have a forged counterpart, FWIW.
Cranks are available with the 360 main and the 3.31 stroke. IDK know if you have a machinist that would know or can regrind the crank. Which is not a bad option and relatively inexpensive.

Good luck with the build.
So Rob just to be clear I can get a forged steel crankshaft 3.31 stroke with 360 mains and I can use my forged standard bore 340 Pistons and my Factory 6:45 340 rods also I would like to know can I internally balanced this assembly your help is appreciated thank you
 
IF! You can get a forged (or cast) steel crankshaft (with) 3.31 stroke with 360 mains, then yes you can use the 340 slugs. A machinist will tell you if he can cut the stroke down. This crank used to be offered. IDK if it is still available.

The balancing job can and should be done internally.
All small block rods are the same length. There “Girth” are bigger on the 340 & 360 engines.
 
Sorry if I posted a confusing message. I just re read what I wrote. I’m a bit scattered in my thoughts. My bad, very sorry about that. I’m normally a good bit clearer.
 
Sorry if I posted a confusing message. I just re read what I wrote. I’m a bit scattered in my thoughts. My bad, very sorry about that. I’m normally a good bit clearer.
No problem at all Rob I thank you very much for the information just trying to use up some spare parts for a 360 block that I was given have a good rest of your night and a good rest of your week
 
Bob, I don’t have all of my books at my fingertips, I could have sworn there was a 360 journaled 3.31 stroke crank once available but I can’t find it and I think I made a mistake in saying there was.

Check with a crank grinder to see if he can regrind the 360 crank throws down. But this may turn into an expensive endeavor I don’t recommend.
 
There was a Mopar Performance 3.31 inch stroke with a 360 main forging (and a cast crank too!) available but you would probably have to find a used one now.
 
The 318 low comp truck pistons can fit on a cut down (318 size) mains 360 crank with open heads and some fatty .090 cometics. Take a little off the edge of the piston and your good to go.
 
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