I used Compstar H profiled rods on my stroker, mainly to reduce the amount of block clearancing and cam shaft lobe clearance on a .550 lift roller. I even went to the trouble of using a small base circle cam, only to find out later that these rods would have cleared the lobes on a normal sized lobe roller. But it still worked out well for me as I really did not need to do a lot of block grinding but I did anyway , just to be safe. I allowed a mininum of .100 clearance near cly bores and oil pan rails. Just small touches of a grinder did the trick. I used and early 010 hi nickel content block.
Felt good about using large cap screw type rod bolts.

 

I like the Eagle SIR 5140H Cap Screw for stock Replacement Rods; however, Scat make a nice 7/16" Cap Screw 4340H Rod for a few dollars more.

 

Scat makes a couple of decent pieces. I'm using the capscrew "I" beam, 4340. I don't think Scat makes a 5140. I've had better luck with Scat being closer to spec than Eagle.

 

The H beams will be better regardless, their I beam orientation is in the right position to resist the bending moments. The 4340 H beams will be even stronger.

It all depends on the power you want to make for whats best for your application. Like zdld said though, I would still get the small base circle cam and clearance the block just in case, even if the rods cleared.

Tensile Strength
5140 steel 115,000 psi sportsman-grade forging
4130 steel 120,000-125,000 psi premium alloy
4340 steel 140,000-145,000 psi strongest alloy for cranks and rods

 

Thanks for the input,looks like H beams for the little diff. in cost !:beers:

 

Generally speaking 4340 is better metal for connecting rods. The numbers indicate things like what metals and alloys are used and percentage of carbon in the product.

 

The last two digits of the number indicate the carbon content, the first two indicate the material composition (generally speaking). In rare instances the numbers can have an added digit because the carbon content is higher (above 1%).

Example 4340
43 indicates the metal alloy group
40 indicates .4% carbon.

Examples of metal alloys can be found here.
http://www.thefabricator.com/articl...m/article/metalsmaterials/carbon-content-steel-classifications-and-alloy-steels

These do not indicate the type of process it went through but does indicate the material concentration.

Just to give you an idea of what those numbers actually mean

 

IMHO, you're not getting to the power levels when you'll see the advantages of a more expensive H beam rod. What's the use in having a rotating assembly that'll hold to 1000hp when the stock block will give up at 600?

 

Stock blocks give out at 600?!?! I got one block thats .06 over thats over 600 at the wheels (LT1 but same thing) and my SBC 78 block is right around 600 and shes fine. That is why you sonic check your blocks.

Personally I have not seen this been an issue unless you had thin walls which probably means you bored and honed the block without checking thicknesses.

 

600 plus will push the mains out of the block on a stock GM block period. If H beam rods are so good why don't the hi end rod designers make there rods like that ?

 

In my opinion if you want to push more then 450Hp out of a OEM SBC and want Perf + Dependability, you should consider a BBC or go EXPENSIVE aftermarket, including block.

I've built 425Hp 8000pm OEM 327's that have over 40,000 miles on them. After 40 years of engine building, only one Blew Up and it was mine - Don't ask me the RPM - Today, I just Doddle around with a 460ci SR 625Hp OEM MK IV on Pump Gas.

I have a Modified 68 OEM 11.25:1 327 450Hp in my Closet - Love them Engines and My Lord they are a Sweet Hearts BUTT!!! ;o)