small block chevy valve train question

- G
- Gino Cetani
  
  Contact options for registered users
posted
20 years ago

Sat, Jun 28, 2003 3:56 AM

I need some advice, I have just installed one replacement cylinder head on my 1974 Chevy truck with a 350 engine. During the installation I noticed that the push rod guides in the cylinder head are round rather than the other sides sloted. The holes are much larger than the push rods. Will this work? I am afraid it is going to cause all kinds of noise once running. Are there different pushrods for this head? I don't see how even a different push rod will work because the holes are completely round. I don't recall ever seeing a small block chevy head with these round holes as push rod guides. The head I have does not have screw in studs.

thanks in advance

- S
- Steve W.
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sat, Jun 28, 2003 3:22 PM

Not without guide plates.

- J
- Jones
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sun, Jun 29, 2003 1:38 PM

- S
- Steve W.
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sun, Jun 29, 2003 9:36 PM

It depends a lot on what head you have. GM SBC heads will all interchange up to the second generation series. However some had integral guides cast in (those are the slot style holes) and some used guide plates mounted to the head with screw in studs. Usually the base heads were the integral guide style, with the hi-po stuff having screw in studs and guide plates. GM also had a few heads in the first series that were intended only for HI-PO use and that used a paired roller rocker setup. Those heads have a large push rod hole and use no guide plate as the rockers cannot move around due to the linked shaft. Sounds a lot like the head Gino got are those heads. Unless used with the proper rocker arms they won't work, standard ball socket rockers have to have a guide to keep them on the valve stem and pushrod, without the guide they walk all over the place. They also may not match the combustion chamber in size and shape as the old stock head either. That could cause real problems beyond the push rod problems.