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-   -   Used roller arms on a different head? (https://moparforums.com/forums/f62/used-roller-arms-different-head-14429/)

74Runneer 03-11-2013 01:32 PM

Used roller arms on a different head?
 
So I'm sure you guys are getting sick of all my questions, but can I put the roller arms from my cracked #302 heads on to another pair of #302 heads that i got from a junkyard? (they just come with the valves and springs) Also can I use the pushrods that are in my 318 now with these heads? If not can i use the pushrods from my cracked #302 heads? I know excessive wear can occur if these parts are mixed matched but maybe these will work? Thanks!

jacilynn_s 03-11-2013 04:04 PM

Okay. Your talking about the swirl port heads that were made from 86 or so up vs the 'magnum' heads. I did not think the arms and shafts interchanged.

If the arms and shafts do interchange with the oiling holes in the correct spot then you would have to use the lifters, pushrods from the roller setup. If you are going with the older shaft and rocker setup then use the lifters and pushrods. They dont interchange, well you can but it's a seriously bad idea.

Gorts 5th 03-11-2013 05:03 PM

Just leave them in the same spot on the head/ rocker shaft.
shouldn't be a problem.
keep asking questions the only dumb one in the one you don't ask.

PK1 03-11-2013 05:25 PM

No one on here is sick of your question. Not even close. Ask away.

I read the post and cant figure out where the Magnum head comes into play from Jacilynn-s reply? If I missed this in another post ignore the following. If not then here:

From what I did read you want to do a simple rocker swap from one 302 casting head to another? Basically a reman or replacement head repair?

YES! Have at it. Reuse all your old stuff. Keep your lifter in the exact bores they are in. Dont move those around.

Here's the legal disclaimer. The casting must be the same or close to same. This isn't a Cup Car so don't get in the weeds of super close tolerances but they should be set up the same.

Same installed height
Same retainer OD to clear rocker arm body
Same casting thickness to keep push rod close

Just ask the supplier.

If they used different valve lengths or aftermarket springs and label these performance then you need to pause and see what the difference is. If OEM replacement your good.

Use a quality head gasket as the two deck faces are new to one another.

Chryco Psycho 03-11-2013 07:46 PM

So all you are doing is swapping heads to the same type & re-using the rockers , no problem , the old pushrods should work fine unless they are bent , just roll them to be sure . Not even sure where swapping lifter comes into play ?

74Runneer 03-11-2013 08:09 PM

Sorry for the confusion. I have a 74 roadrunner with a 318. I want to up the performance and fuel economy a bit so i bought some swirl port heads to replace the stock 74 318 heads. These 302 heads came with the roller arms and lifters and pushrods, springs, and retainers. So I got these magnafluxed and turns out they were both cracked beyond repair. I ditched the cracked heads and kept everything else that was attached to them. Im looking for another set of #302 swirl port heads but the ones i found didnt come with roller arms, lifters or pushrods. I wanted to know if it would be a problem if i used the roller arms and lifters from my first 302 that was cracked and put those on my new #302s that arent cracked. They are both the same style heads and roller arms etc. They just weren't originally with the second set of 302s.

Also, when i put these 302s on my 74 318, can i just use the pushrods that were originally in the stock 74 318 with these 302 heads or do i have to use the ones that went along with the lifters from the 302 castings? I believe the 1974 and 1988 pushrods were the same dimensions. I mixed up all the pushrods from the newer 302 heads so preferably id like to use the pushrods that are in my 318 right now because they are all in order and match up with the cam. (of course id only use them if they were straight and not worn down.)

And yes i bought a nice new fel pro gasket set that should work great

74Runneer 03-11-2013 09:02 PM

Also would it be a bad idea to mill these heads .2 or so to improve the sealing surface and add a little compression? Would this even make a difference?

Gorts 5th 03-12-2013 05:29 AM


Originally Posted by 74Runneer (Post 99432)
Also would it be a bad idea to mill these heads .2 or so to improve the sealing surface and add a little compression? Would this even make a difference?

mill them 0.20... you should have good compression

PK1 03-12-2013 12:02 PM

Search the forums for "net lash" It will show you how to measure for pushrods. Easy to do.

Milling the heads will give you MORE compression. As to how much more?

You need a couple things:
Head gasket compressed thickness and bore
piston placement in hole at TDC and design cc of piston
head cc

Summit has a good calculator.

74Runneer 03-12-2013 03:09 PM

I dont know the piston placement but I just got my heads today and they had the roller arm and lifters on it!!!! So I just sprayed the keepers with the magical wd40 to loosen up the keepers so i can get the valves off to get the heads cleaned up at the machine shop. I'm not sure if I'm even going to mill them, these are pretty clean and looks pretty straight. Ill have the machine shop check if they are straight and if they arent ill have .015 or so off to give them a better mating surface and up the compression. But they look very good so i think ill just end up using my stock pushrods. Thanks for all the help!


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