Hi,

can i use Magnum 1.6 Roller Rockers with these modified Vortec Heads? And how much must they be milled down to fit a 305. Ive seen different numbers when searching the forum.


Nebu.

 

As long as there self aligning they will work fine. If not you will need to have pushrod guide plates installed also. The machine shop should know how much to take off to get the right cc volume you need to keep the stock compression. If you ever plan to use these heads on a 350 they will have too much compression to run pump gas with a good preformance timing curve.

Steve

 

You will need the self aligning, I think they make them but you might have to get a different model (the roller tip ones won't work, they're not SA). With the heads if you use a steel shim gasket, F/T pistons (assuming -4cc) and keep the 64cc chambers with a std .025" deck height, compression will be 9.2:1. You can mill the heads to 60cc, use a composition .041" thick head gasket and compression will be 9.25:1. If you zero deck the block, use a steel shim gasket (.021") and keep the 64cc chambers you're looking at 9.6:1.

Personally, I don't like shaving heads since it reduces the deck thickness on the heads and some aren't that thick in the first place, plus should you go to put them on a bigger motor the compression will be out the roof and you'll be wishing you didn't shave them.

 

I'm running guide plates with mine. It's kind of a trade off, as the price of non-self aligning roller rockers are much cheaper and easier to find. Just make sure you use the proper puch rods, or else the guide plates will eat them alive.

 

www.enginekits.com sells some vortec roller tip self aligning rocker arms for 120. Might want to check them out.

 

Yep, hardened pushrods are a must if running guideplates....

 

I have the CCA-1418-16, Magnum Steel Roller Tip Rockers. They are self-aligning and the CCA-7808-16 High Energy Pushrods 7.195 in. long. (hardened)
So i dont need guideplates and it will work fine with these heads?

 

I ran stock pushrods with my guide plates, 6500rpm and all, and not even a scratch on the rods. I've got a set of hardend ones ready to install this winter though.

 

Yes they will work fine.