Ok I decided I will swap a set of LG4 heads on my LO3. But I have few more questions. Can I use my later guided rocker arms on the older heads? Can I use my stock ( roller cam ) pushrods with the newer rockers, planning to run LT1 cam. Will the later rockers fit under perimeter bolt valvecovers ( looks like they have more clearance to me )? Do the earlier heads have a spot for the fan switch?

 

• 1. Yes, if you have the slots in the heads drilled out so that the push rods can go wherever the rockers want them to go. You can't have 2 systems trying to control the rockers.
  
• 2. Yes.
  
• 3. AFAIK yes.
  
• 4. Yes. All heads have that place, its size changed over the years, but LG4s have the correct size.

You shouldn't use your stock rockers. They are junk, and will reduce the effectiveness of your cam swap, by bending under the stress. You should get something better then the stamped sheet metal ones: I'd suggest Comp's roller-tip ones as a good bang-for-the-bucj option. If you do that, you can avoid the machine work to the heads by getting the non-"self aligning" type. You should also put better springs on there; any of the major cam mfrs. entry-level spring would do, such as Comp 981 or the equivalent Crane, Lunati, etc.

 

Ok, what if I use the non-aligning rockers that came on the heads originally, can I still use the factory roller cam pushrods. What I'm really asking is are they the right length, the pushrod hole is very small I'm worried about pushrods angles with the roller lifters. I know that the stock rockers are POS, I plan to swap in better ones when I get the funds ( maybe some 1.6s ). However. I need a for-now solution. Yeah I gettin' springs too.

 

Yes that combo will work. Stock push rods come in exactly 2 lengths: one for flat-tappet lifters, and one for roller lifters. The heads & rockers don't make any difference as to hich length you use.

The small holes in the older heads are designed to be the guide for the rocker, to keep it on the valve.

 

Ok, kinda like a guide plate. Thanks for the info.