head bolts and such

[superj]

So, all the reading and I cannot remember if my headbolts will work when I swap the 4.2 head for the 4.0? Also, what about the push rods? Will they work now? I am not doing the 4.2 / 4.0 mod, I am going back to just a 4.0 and since that is my situtation, I cannot remember what I read about that part of the swap, anyone got any ideas?

 

[LGR]

I think its up until 87 the the 258 used 7/16. Later models used 1/2. All the 4.0 heads should use 1/2. Not 100% though. I've seen people reuse old push rods and new ones. You should buy a set of new bolts, they say they should be changed when swapping heads.

 

[superj]

the 99 bolts are stretch to yield bolts then? i think i remember reading that because bmws are the same way. i just couldn;t remember about the sizes and the push rods