Small block w/ 3.79 crank

go-fish said
@ValiantS @tvt59 @TT5.9mag

I, like @mopardude318 , am putting together a 3.79 piece meal. After seeing the longer rods in question it makes me wonder if I put the cart ahead of the horse on one of my purchases, rods. And, I'm only two components deep into my parts collecting!

I have a virgin NOS 5.9 bare block I bought from John Irving that MP gifted him during the Magnum 380 crate engine days. Later, I looked at the Monar site and got the spec for the rods, minimum 6.125". So I bought the chevy rods that is 6.125, 2.1 journal, .927 piston pin, ....

Molnar's crank:

360-3790FB6FSmall Block Chrysler -2.100" Rod Pins3.7903602.1006.125


My rods:

Brand:
SCAT Engine Components
Manufacturer's Part Number:
2-350-6125-2100A
Connecting Rod Length Center to Center (in.):
6.125 in.
Connecting Rod Material:
Forged 4340 steel
Wrist Pin Style:
Floating
Pin End Bore Diameter:
0.927 in.
Rod Journal Diameter (in.):
2.100
Big End Bore Diameter (in.):
2.2250
Quantity:
Sold as a set of 8.
Cap Retention Style:
Cap screw
Big End Width (in.):
0.940
Clearanced for Stroker:
No
Connecting Rod Bolt Brand:
ARP
Connecting Rod Bolt Diameter:
7/16 in.
Connecting Rod Bolt Material:
ARP2000 alloy
Fastener Tensile Strength (psi):
200,000 psi
Connecting Rod Bolt Head Style:
12-point
Weight Matched Set:
Yes

There's a set of pistons that Richard Nedball is selling that I was thinking would work with my rods. [FOR SALE] - New BRC 4.030" Forged Pistons and pins for 3.79" Stoke Crankshaft

It would be nice to pick these up if they work with my rods. Piston wrist pin is .984 but my rods have a pin diameter of .927. I figure the rod pin hole can be bored .057"?

In retrospect, its better to rat hole your money instead of rat holing parts so you can buy everything at the same time. I would be very pleased if the rods I have will work, especially with the pistons for sale.

Now, as was mentioned 6.5' rods will have a higher rod ratio that 6.4" rods so the shorter rod will be better for wear and longevity? Is it better the shorter the rod is? Would a shorter rod (6.125) and taller piston be better for stability?

I apologize if these are elementary questions.
Click to expand...

Connecting rods are bushed. It's just not cost effective to push out a bushing, bore the hole oversize, re-install a bushing, bore, and hone for .002" difference in rod length.

You are not going gain anything by increasing the rod length from a stock 6.123" to a 6.125". Sell the Scat rods and just get a set of 6.123" x.984" rods

Having more compression height aids to piston stability within the bore and allows the use of a nice ring package. This is specially important to me on a street engine.

Most importantly to me is that one builds a combination that is serviceable should you need replacements. Using off the shelf parts is the way to go for 99% of builds.

Custom piston prices are now $1600 and up and should you need a replacement piston down the road your looking at $300 and at least 16-weeks to get one.

Tom