When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm getting the block machined and I'm installing new .30 over flat top pistons with a nice Lunati cam. Planning on using Trick Flow heads, new ignition system and 750 cfm carb. When finished, the targeted horsepower for engine is 400 hp. Should I use these my stock OEM rods or should I use these new rods? They cost $300 new for the set.
Shown above is our BRAND NEW 5140 forged steel stock replacement AND performance rods. These rods use a 7/16" capscrew, a premium design borrowed from our high end H beam style rods, which is much stronger than the older factory style "bolt with a nut on the end of it." Finally, a rod that works great for stock replacement press fit pin applications as well as high performance engines at an incredibly reasonable price. Forget about reusing 40 year old stock rods! We now have an option that is many times stronger for considerably less money! The beam shape and size on these rods is modeled after the famous (and super strong) 426 Hemi rods. These rods use a non-bushed small end for factory size 1.094" press fit applications. Length is factory RB at 6.76." Both the big and small end housing bore are finished to precision tolerances on AMERICAN MADE Sunnen Power stroke honing equipment. One other important fact to remember is that metal has what is known as a fatigue life. Everyone has bent a paper clip back and forth so many times until it breaks. Once it breaks, it has reached enough "cycles" to get beyond the limits of it's fatigue life. Connecting rods are also made of metal and also have a fatigue life. Every time the piston fires, the rod is compressed and every time the crankshaft turns back around, it drags the piston back down from TDC. This causes the rod to expand and contract, or "cycle" just like bending the paper clip back and forth. The only difference is that the rod is much stronger than a paper clip (unless maybe you're talking about Ford rods) and it's being cycled millions of times as the engine is running. The more cycles on the rod, the weaker it will become, and the closer to failure your engine will be. These rods are BRAND NEW, so they will always be starting with ZERO cycles on them. That alone is worth a huge amount of strength. After forty years and thousands upon thousands of miles, do we really know how many millions and millions of cycles those old factory rods have on them? With the cost of cleaning, magnafluxing, resizing, buying new bolts, etc, etc with a set of stock rods, going with our new aftermarket version is a no brainer!!
For 400 HP, I'd just have the stock rods balanced with the rest of the engine.
Newer, aftermarket rods can be lighter and free up a little HP, but not worth the expense, IMHO.
Also, the stock heads with just a little porting will do well over 400HP, depending the cam specs, but it's your money
I agree... For 400hp your stock rods should be fine,
Now with all these other parts, if your going to buzz it up in the RPM range.... That's a different conversation and a way different budget format..
