1989 454 Crusader. Are these rocker's adjustable?

I just had the heads rebuilt after the boat sat for multiple years and stuck multiple valves and bent a handful of pushrods.


I have installed the heads, installed all new hydraulic lifters and I am having a hard time finding new pushrods that are the same length.
I ordered a set of what I thought was stock pushrods (9.200" & 8.230" @ 5/16"). When I got them I realized they were short (lash at bottomed out rocker nut) so I went and ordered 9.250 & 8.280" which matched original in length, but I didn't realize they were 3/16" diameter.
To fix this I ordered new guide plates for the larger diameter pushrod but the guide plates are thicker than stock and raised the rocker arm and those now do not fit without lash.


My question is, are my rockers adjustable? I've read conflicting theories online..


With the existing pushrod I can hand tighten until all lash is removed and I can only get another quarter turn until the nut bottoms out.
Can I just buy a longer pushrod and tighten and add half a turn and not have them bottomed out?


Hope I am explaining this correctly...


See attached photo.

assuming it is original, an 1989 should have been a Mark IV block, so your valve train is adjustable from the factory.

What is in the pic is a full roller rocker which isn't stock...which suggests somebody has been inside that engine. Those rockers require additional work to enable the valve covers to work - or you get mid height covers.

The best thing to do is to measure what you have and then order what you need. A good machinist can help, especially if previous work has changed an OEM dimension...

Thanks Mark!

What I just realized is that within the rocker nut there is an adjustable hex bolt threaded within that allows adjustment of the rocker nut. Although this is probably pretty obvious to most, this is my first time doing this type of build.

My question is; when adjusting lash do I tighten the rocker nut until all lash is gone (on the flat of the cam / valve fully closed), add a half turn then tighten the hex nut within?

Hope what I'm asking makes sense.

Also I was unable to find the exact size pushrod that I started with. I am able to find pushrods that art 0.1" under and over and they will work with adjustment. Which one should I go with? Is there an advantage to having a longer or shorter pushrod?


Thanks,

Bill.

what you described is what you need to do....the trick is how one determines zero lash.

you want the 'correct' length push rods to maintain the optimal geometry of the valve train...i would say start with the stock ones and go from there.

you may also want to do a search on <adjusting poly locks> .....

Thanks Mark!