Is a hydro bus block different?

[JP Noonan]

I have a GE bus block that came with hydro lifters. Are the oil passages different? I can't tell when I've compared it to some EA and W blocks. There is a re-inforcement in the cGE ase next to the #1 cam bearing boss, but that's it. I had planed on using the Web hydro performance cam but with the last thread I'm not sure.

Do buses with stock hydros make the same racket on warm up as 914s that have been converted? I have all the hardware, heavier springs, solid spring separators, and pushrods.

My therory is the bus block oil passages get more oil to the lifters, but anyone know for sure?

[Jake Raby]

The hydro engines have a filled and plugged area to boost the oil pressure to the lifters, for a better "pump up" and operation. The cases with solid lifters have a relief valve in this area..

It is fine to use the Hydro case for solid lifet, but you cannot use a solid lift case for hydro without modifying the pressure relief.

I'm not saying anything else about the Hydro stuff, just read that thread closely and make your own call.

[JP Noonan]

Thank you both.