the accessories holes are not drilled the same, i slammed a screwedriver into where the holes would be and all i got was nothing. i dunno how but thats what I got. I'm not gonna swap them anyway. I'll probably get a tap later, but first, a much bigger problem has popped up. and this probably requires a whole new thread but here it goes anyway.

So i didnt want to swap the heads as my first action anyway, first i pulled the valve covers to make sure the rockers were still in full motion and the valves were closed all the way at TDC, well i found that one of the valves wasnt moving at all, i think it was the intake valve. So i checked and found that the nut was loose on it. I went to tighten and instead ended up stripping it. (ya, oh crap). i pulled the other valve cover and found several more loose rockers on that side, so I assume i didnt tighten up correctly during the re-installation process. I'm working on getting a set of roller-rockers so i was gonna replace the springs and pushrods too, but now can i replace the the stud bolt? Are they welded in or are they screwed in? I really hope screwed in cuz i dont want to have to replace them already...although a set of GT-40 heads sounds fun...anyway, what do you guys think? thanks in advance.

 

they are pressed in. if you want roller rockers you will be having the machine shop remove the old studs and drill & tap the heads for the screw-in studs and guideplates anyways. (you HAVE to if your giong to use roller rockers). also you'll need hardened pushrods. you dont have to change valve springs unless your cam needs different ones, stock setup is good for around .475 but with springs being close to 40 years old anything over .450 could use a new set.

 

actually I was just gonna use stud mounted rollers..but ok

 

Rockers will appear loose when
1. lifters are not pumped up
2. not opening the valve

When you install rockers you have to do it when you are the compression stroke of the cynlider (for intake side anyway)

 

lol, i know how to install them, just that i kind of cant,lol.

 

Bring us up to speed, here. You rebuilt your engine? Put in a 'Big Cam' (from sig) and didn't do anything to the heads? Yep, bad idea. I did that at one time too.

Roller rockers have to way to center themselves on the valves. You'll notice your stockers have rails that ride on either side of the valve to keep it straight. Also, make sure you do not have any valve caps on your valves or roller rockers will destroy them. So, you may be looking at new valves.

Since you're pulling the heads, take 'em to the machine shop and have them set up for screw in studs and guideplates. You will need your guideplates in hand, or at least know the thickness for the machining to be accurate.

You'll also want new springs to match the 'Big Cam' (from sig). Get whatever springs the cam manufacturer recommends.

Keep track of the cost of all this. Aftermarket iron heads all ready to go will run you a little less than $1k and work a whole lot better than a 100% stock casting with screw in studs.