what is a better base line std stock short block for power with 11 1/2 to 1 pistons i havent done the machine work on my 360 w5 motor and was thinking would a 340 make more hp and be just as strong ??? thanks guys ! mopar or no car ! i havent got my pistons yet im willing to buy a block and crank

I love 340's because of the way they rev. But everything else being equal the 360 will make more power and be easier to find parts for.

Conventional thinking has it that 340's are more rev friendly due to their shorter stroke ie. 3.31 vs 3.58 for the 360. I am not so sure that I buy that argument. When using the same brand and model piston, the 340 piston will be heavier due the greater compression height required. It seems to me that the heavier piston pretty much negates the advantage of the shorter stroke. Now a 340 may need to rev higher than a 360 to achieve the same power, but that dosen't necessarily mean it revs quicker. Given cost, availability and probably a broader power band, I would go with a 360 in most cases.

340 with its bigger bore... if you were buying a crank
you could stroke it and end up with more CI... plus
the bigger bore would unshroud the valve better

Look at a stock 1972-73 340 piston and weigh it if you can and then look at a stock 1974 360 magnum piston and weigh it. There is only .040 differences in the bore I like using a 4 inch stroker crank in a 340 block If I have both blocks, if not a four inch stroke crank in a 360 block(there cheaper and easier to find)works well also

stock stroke short blocks, a 360 will make more power than a 340, because it is 6% larger in displacement.

now STOCK short blocks, I'd take a pre '73 340 over any 360, because with STOCK PISTONS, STOCK compression ratio will be much higher.

We tried both in same car. All same parts that would interchange were. Cam, indybrock heads, and super victor intake. 72 Cuda 2780 lbs. In 1/8th 360 went 7.11 with the same parts on the 340 it went 7.01. The 340 was 11:1 the 360 was 10.5:1...

DON'T GET OFF TOPIC, HE IS BUYING PISTONS

The 340 and 360 block are basically the same before machined. The 340 has a larger bore but the 360 block will take the same bore. The 360 has larger main journals which means more speed in the bearing and more oil to lubricate. Some have done conversions with spacers and 340 aftermarket caps.

My understanding is a choice between 340 or 360 shortblock and order pistons and get machine work done. This was the original question. Not an arguement between 340 and 360 engines.

I had a 360 bored .100 over that made 378 cubic inches. We turned that engine 8,500 with W2 heads and aftermarket rods. Great combo. Most are not looking to spend a lot in valvetrain to turn the big RPM. Most would be reluctant to bore to 4.100" although it is a safe bore for a street engine if you sonic check the block first. .070 may be a safer choice which would get you a 4.070 bore giving you 372 CID. I like bore. The 340 came with more bore allowing more head flow and the fact that it came with 2.02 intake valves didn't hurt either LOL. It would be nice to get to a 340 main bearing and have a 4.100" bore with a 3.58 stroke. But, I'm guessing you are on a limited budget. Go with a 360 because they are cheaper. Look for 74' and older blocks if you want the larger bore. Later blocks may not be able to hold over 4.070". Just have the block sonic checked first before boring it is not expensive. Then bore to a safe bore and buy pistons. You will have a very inexpensive shortblock this way. Although cranks are incredibly cheap and there are a ton of 408 spinning assemblies available these days as mentioned.

Leon