These are not stock GM small block hydraulic lifters - you need to make sure that they are the solid lifters. From the outside the solid and hydraulic lifters look the same. The pushrods normally used with them in the B20 are not stock GM pushrods. IPD has used different pushrods in their " high rev "
lifter/pushrod kits, and some of them had real problems - bending, tips coming off, etc. Not sure what they are offering now but there are real differences in quality.

Cams - the Isky/IPD cams are all very old, outdated designs.
They are popular because they are cheap and can be sold to people who do not know that there are much better cams available. You can't just go by the cam specs as they don't tell you anything about the most important aspect of the cam design - the shape of the lobes. And that is where the biggest changes have taken place since the Isky cams were designed.

John
V-performance.com