Your question leaves so much to be guessed at that it doesn't have an answer.

Here are some things I think about when I read your question:
1. Why do you need new rods?
2. What are you doing with your engine that stock rods won't work?
3. What's wrong with the rods you're running now?

For a street engine that doesn't see more than 5000 rpm, the stock rods usually lasted basically forever.

The part of a connecting rod that usually gives trouble is the big end. The highest force the rod sees is at the end of the exhaust stroke. Rod bolts stretch and loosen the crush on the rod bearing, and/or big ends distort.

For years and years the Carrillo rod was the best that could be bought. It was an H-beam.

When more got into the aftermarket rod market, most of the first generation rods were also H-beam. I maintain that's because you could create an H-beam rod out of a piece of steel plate. No forging equipment required.

When the aftermarket rod industry took off (and a lot went overseas) there started to appear reasonably priced I-beam rods. Economics of scale allowed the manufacture by forging.

In the beginning, H-beam rods were heavy. I maintain they have the beam material in the wrong places. But as time went by, the H-beam became lighter and lighter as better design techniques were used. Now, the difference in weight between a really good H-beam and a really good I-beam is meaningless.

Go on Ebay and look at the used racing rods. There are some of each style. That means to me that either style can be used in the most demanding applications.

If you have to or want to change your rods for I-beam rods, the best two that come to mind are the Oliver parabolic billet and Crower billet rods. They don't come cheap.

R.