Installing 1974 304 heads on 1979 304 block

[OEM1984CJ7]

Ok, I got the rebuilt heads and they are 1974 cast numbers and my engine is a 1979. I just have a couple of questions before doing the swap on my next day off.

1. 1974 heads on 1979 block ok? I assume so as I have read others have done it.
2. Use copper spray on the fel-pro head gasket or not?
3. When removing the rockers and pushrods from existing head do I need to slowly remove the rocker bolts a turn at a time or just remove them all in order to keep from warp/bending the bridges?
4. When reinstalling the rockers and push rods on the new heads after installing heads on block I just do as the manual states and install them and tighten one turn at a time until they are torqued propery at 20 lbs and they are done? No TDC on each cylinder to tighten them?
5. I know that none of the head bolts need sealant but read somewhere that the intake manifold will need sealant on the two front and two rear bolts? Black RTV?
6. Can I use black RTV on both sides of the new valley pan on the intake ports and water ports?

Sorry for all of the questions but I hear different things from different people in their installs and just want to get it right.


thanks.

 

[OEM1984CJ7]

And one more question....Will the hyd lifters leak down and cause an issue when reinstalling push rods?



thanks.

 

[OEM1984CJ7]

Surely someone here has replaced heads and intake before.....

 

[CJim7]

Ok, I got the rebuilt heads and they are 1974 cast numbers and my engine is a 1979. I just have a couple of questions before doing the swap on my next day off.

1. 1974 heads on 1979 block ok? I assume so as I have read others have done it.
They should be just fine
2. Use copper spray on the fel-pro head gasket or not?
No. Very important, use nothing on the headgaskets
3. When removing the rockers and pushrods from existing head do I need to slowly remove the rocker bolts a turn at a time or just remove them all in order to keep from warp/bending the bridges?
I always end up bending the bridges when removing them no matter how careful I am. And then I end up straightening them back up...never had an issue.
4. When reinstalling the rockers and push rods on the new heads after installing heads on block I just do as the manual states and install them and tighten one turn at a time until they are torqued propery at 20 lbs and they are done? No TDC on each cylinder to tighten them?
You dont need to worry about tdc...just tighten them down to spec.
5. I know that none of the head bolts need sealant but read somewhere that the intake manifold will need sealant on the two front and two rear bolts? Black RTV?
I have heard this...however, I have never used sealant on those bolts. I do however, use copper spray gasket on both sides of the valley pan and a ring of black rtv around the water jacket ports front and back.
6. Can I use black RTV on both sides of the new valley pan on the intake ports and water ports?
Yes. As I explained above, just dont over-do it. be sure to use the copper gasket spray on both sides of the valley pan.

Sorry for all of the questions but I hear different things from different people in their installs and just want to get it right.

This is how I have done the installation each time on these engines and have never encountered a problem.


thanks.

 

[jeepboy45]

@Jim:
When you use the black RTV on water jacket ports, are you talking about the intake or the heads..... or both surfaces?

thanks
brian

 

[OEM1984CJ7]

Thanks Jim!

On the copper spray, do you mean spray it on top and bottom both sides (ports) of the valley pan and then RTV the water ports? #6 question.

Thanks again

 

[CJim7]

Brian,
I lay a light bead on the heads around the ports, then install the valley pan, then another light bead on top of the valley pann before installing the intake manifold. i've never had an issue with water seapage.

On the valleypan, i copper spray the port areas of the bottom side first , then carefully spray the port areas on the topside after installation. Be sure to allow the copper gasket spray to set up before installing on the heads...and again before installation of the manifold.
The nice thing about this spray is it lays out very thin and you can build it up with a few coats if you desire. This ensures you aren't gunking things up or creating bad seals.

Pay special attention to the rubber end gaskets on the block....they almost never fit correctly with the installation of the manifold. I build up the RTV pretty liberally on mine to keep...more then I really like, but these things tend to leak.