Someone needs to start re-casting 340 blocks

-
Demonic said:
Run a thermocouple off the side of the main caps, or something similar. and compare heat rise at the same time.
Click to expand...
I'm not arguing there's a difference. Just how much?
 
I did a 427 inch SB a few years back using a Mopar 340 resto block. That was a nice block, kind of heavy and had a few weird things going on, but seemed like a really nice casting. My spreadsheet says I paid $1457 for the block. Probably spent another $1000 in machine shop time fixing stuff. It would be interesting to find out why Mopar stopped making them. They had the tooling in place and it was probably paid for but sales must have been too low to keep production going.

dougsp.jpg
 
And what happened to the tooling for the 340 resto block? If Mopar didn't want to make the blocks anymore why didn't they sell the tooling to someone like Dart? Or ship it to China and let ProCopyCat make them?
 
Killer6 said:
Oh, You can be sure there has been, just not Nick's or the like....the teams doing it had a reason for doing so, would the avg. Rodder benefit?....not enough to justify the $$$$ for sure.
Click to expand...
I can surely see the benefit of it IF that's not the only thing done. Mods like that stacked together will reap way more benefits than small stuff like that by itself.
 
AndyF said:
And what happened to the tooling for the 340 resto block? If Mopar didn't want to make the blocks anymore why didn't they sell the tooling to someone like Dart? Or ship it to China and let ProCopyCat make them?
Click to expand...
Same reason Chrysler wouldn't let us use the Pentastar when we founded The Middle Georgis Mopar Club about 30 years ago. We sent a letter to their legal department asking permission just to cover our butts. They said no. We did it anyway. lol
 
273 said:
If it was anything substantial you'd think people would notice it by now when building similar 340 and 360.
Click to expand...
ounces add up to pounds.

you do enough of the little stuff and reap bigger rewards. say running the smaller smaller journal lets you run a smaller bearing, that heats less, which means you can run it harder, longer or at a higher rpm without failure and it has less parasitic loss. it might be worth .25 HP from idle to 4K but if it's worth 5 from 5200~7000 and it keeps the engine in one piece long enough to finish the race then that's a worth while upgrade.
 
junkyardhero said:
ounces add up to pounds.

you do enough of the little stuff and reap bigger rewards. say running the smaller smaller journal lets you run a smaller bearing, that heats less, which means you can run it harder, longer or at a higher rpm without failure and it has less parasitic loss. it might be worth .25 HP from idle to 4K but if it's worth 5 from 5200~7000 and it keeps the engine in one piece long enough to finish the race then that's a worth while upgrade.
Click to expand...
I don't know all of the details as most of you guys do. But if the bigger main bearings create a heat problem then why did mopar increase the size of the main bearings of the 360?
 
Dan the man said:
I don't know all of the details as most of you guys do. But if the bigger main bearings create a heat problem then why did mopar increase the size of the main bearings of the 360?
Click to expand...
because 360's are low rpm truck motors, duh.

[caveman]big strong mains more important in truck with granny 4spd [/caveman]
 
Dan the man said:
I don't know all of the details as most of you guys do. But if the bigger main bearings create a heat problem then why did mopar increase the size of the main bearings of the 360?
Click to expand...
Cause they didn't care about a few hp at high rpm, they wanted make sure it would live as a work engine, now days we know cast cranks are pretty tough back then they didn't know as well.
 
AndyF said:
Aftermarket 340 blocks would cost around $4000 and they would probably still have the stupid lifters pointed sideways rather than at the rocker arm. The SB needs a redesign if it is going to worth tooling and I really doubt anyone is willing to invest that much money into the SB Mopar market these days
Click to expand...
Wouldn't it be nice if someone rich say like Jay Leno or someone who would do it for the love or Mopars and not for the love of money.
Opps! Dreaming out loud again.
If I hit the lottery for millions I'll take care of it. There I go again. lol
 
Super-Cuda said:
There are not as many people as you would think interested in 340's anymore since the Gen 3 Hemi's became so popular in A-Body transplants. This conversion is getting cheaper and easier to do every year.
Click to expand...

agreed.. the only reason i did another 360 for our dart is i could do it dirt cheap.. if that motor ever comes out its getting a modern hemi.
 
Killer6 said:
???? The Cleveland engine was the performance alternative to the Windsor period. If You mean swapping a crank w/Cleveland size bearings, & spacer/shim shells, yes, there is less friction. The 360 was designed ground-up as a cast crank unit, & in typical over-engineering fashion, Mopar probably made the mains larger to maintain crankpin/main overlap.
Click to expand...

The main stream thinking of the time was for the 360 to use a bigger crank journal for use in the trucks as a bigger heavy duty main would handle more stress under the work load of heavy hauling.

While this was largely proven wrong years later, that’s the way they thought back then.

FWIW, the smaller bearings offer less friction as spoken about earlier but it’s not a big HP maker but more of just simply less friction allowing the rotating assembly to spin up faster and requires less oil to protect the bearings.
 
rumblefish360 said:
The main stream thinking of the time was for the 360 to use a bigger crank journal for use in the trucks as a bigger heavy duty main would handle more stress under the work load of heavy hauling.

While this was largely proven wrong years later, that’s the way they thought back then.

FWIW, the smaller bearings offer less friction as spoken about earlier but it’s not a big HP maker but more of just simply less friction allowing the rotating assembly to spin up faster and requires less oil to protect the bearings.
Click to expand...


Interesting!.

I am a strict amateur when it comes to crank specs and performance.

I would have thought that a crank would be more susceptible to deflection at higher RPM due to less material in it and therefore less reliable at higher rpm.

I know this is an over simplification but I'm thinking fishing rod. The smaller diameter it is, the easier it deflects when cast.
 
Super-Cuda said:
Interesting!.

I am a strict amateur when it comes to crank specs and performance.

I would have thought that a crank would be more susceptible to deflection at higher RPM due to less material in it and therefore less reliable at higher rpm.

I know this is an over simplification but I'm thinking fishing rod. The smaller diameter it is, the easier it deflects when cast.
Click to expand...
True, but that is where the stronger materials come into play. Forged steel, as in early engines and 4340 billet in race cranks.
 
junkyardhero said:
ounces add up to pounds.

you do enough of the little stuff and reap bigger rewards. say running the smaller smaller journal lets you run a smaller bearing, that heats less, which means you can run it harder, longer or at a higher rpm without failure and it has less parasitic loss. it might be worth .25 HP from idle to 4K but if it's worth 5 from 5200~7000 and it keeps the engine in one piece long enough to finish the race then that's a worth while upgrade.
Click to expand...

Smaller bearings are lighter. That’s one reason why smaller rod throws are generally better.

A smaller throw means a smaller lighter bearing.

NHRA screwed everyone when they banned composite connecting rods. They didn’t need a rod bearing. The rod ran on the crank.

IIRC a standard 2.100 bearing is 52ish grams.

Getting rid of the bearings is a huge weight savings.
 
I’ve got a 71 340 unstamped warranty block, and a 73 340, both standard. If I sell they wouldn’t be cheap.
 
273 said:
We’re they supposed to manufacture different mains for each applications?
Click to expand...

360 was originally conceived for 1971 model year as a lighter, more economical alternative to the 383 in C-bodies which were Mopar's biggest volume sellers at the time. Bigger mains from the start were to improve crank fatigue life due to the longer stroke (in theory). Iirc 1972 they started being offered in trucks, my '72 D200 has a factory 360. They work well in that application, tons of grunt and has the driving feel of a big block. Drinks gas like one too lmao.
 
MopaR&D said:
360 was originally conceived for 1971 model year as a lighter, more economical alternative to the 383 in C-bodies which were Mopar's biggest volume sellers at the time. Bigger mains from the start were to improve crank fatigue life due to the longer stroke (in theory). Iirc 1972 they started being offered in trucks, my '72 D200 has a factory 360. They work well in that application, tons of grunt and has the driving feel of a big block. Drinks gas like one too lmao.
Click to expand...


They work pretty good in race cars too.
 
You must log in or register to reply here.
-

Back
Top