Change of plans. I’m forced to do it.

[pittsburghracer]

Well I got jumpy a few weeks ago when I talked to Ed at Molnar and they only had two sets of 6.125 Chevy sized rods so I ordered a set. The Chevy sized 340 cranks won’t be in till after May sometime at the earliest. Well now that I’m feeling better I tore my 422 apart and low and behold the assembly is Mopar sized including a .984 piston pin. So I called about a Mopar journal 340 based crank and they have the cranks but not the rods. Lol. But the rods are in the United States so they should have them soon and do what they do ASAP. The crank is being shipped this week so I will have to use the rods on a new set of Diamond Pistons I have on my shelf and get a Chevy sized crank to build another 408 in the future. I can’t wait till these shipping delays are over.

 

[RustyRatRod]

Help refresh my memory if you don't mind. I know there is an advantage(s) to the Chevy size. Is it weight? Getting a more affordable part? What's the skinny on it? I just don't remember. Thanks.

 

[pittsburghracer]

Help refresh my memory if you don't mind. I know there is an advantage(s) to the Chevy size. Is it weight? Getting a more affordable part? What's the skinny on it? I just don't remember. Thanks.

Mopar has that crazy .984 piston pin size to start with. Block clearancing on stroker engines is usually easier, rotating weight is also less, rod choices are usually better especially on a big block. Chevy rods are sometimes cheaper for basically the same rod.

 

[RustyRatRod]

Mopar has that crazy .984 piston pin size to start with. Block clearancing on stroker engines is usually easier, rotating weight is also less, rod choices are usually better especially on a big block. Chevy rods are sometimes cheaper for basically the same rod.

Thanks. I thought there was "more than one" reason. I just couldn't remember.

 

[pittsburghracer]

Ohhh I did easily sell my Eagle crank and rods out of my old 422. My fishing buddy bought them. He’s going to either do a. 340 he has sitting in his shop or a 318.

 

[Oldmanmopar]

Usually when the deck is cut under 920 you will need to use GM size pins to keep the pin under the rings on a stroker piston. So the crank will have to be GM size for affordable rods. My GM rodded 421 made 679 @7200 at the crank but it didn't last long. My 416 was 4 inch crank , Mopar size rods and Diamond pistons. Indestructible so we freshened it.

But now my son is tearing it down and is now going with a Light weight knife edged 4 inch crank, Aluminum rods and ross 13-1 pistons. A big question mark on durability but its my sons call.

But the Diamond piston 416 motor did treat us good for 8 yrs. of hard runs.

 

[33IMP]

Mopar has that crazy .984 piston pin size to start with. Block clearancing on stroker engines is usually easier, rotating weight is also less, rod choices are usually better especially on a big block. Chevy rods are sometimes cheaper for basically the same rod.

All of this applies to a big block Mopar with BBC rods too, plus a much greater array of lengths and weights. You can save two hundred grams of piston/pin weight by using a Chevy rod and a custom piston, a hundred grams in the pin alone.

 

[pittsburghracer]

Well I ordered it Tuesday morning and it arrived at 1:45 Thursday. Can’t beat that.