pushrods for magnum head conversion

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DusterBoy15

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what pushrods or length are you using in your motor and is it with a stock deck or zero deck??
 
Those sound like the right ones Dusterboy15. To be sure, I would get an adjustable pushrod, set it up and then measure it. Make sure that any pushrod and lifter set you get is made to oil through the pushrod. You don't want to push lift of the cam to far. I am at .512 and that is it for me. Remember to take the advertised lift of the cam, divide it by 1.5 and then multiply by 1.6 so you will get the proper lift figure for the 1.6 rockers on the magnum head. And yes, if you go above .525 lift you will run into problems.

Jack
 
What springs are you useing ? LA springs and retainers wont work on Magnum heads.
 
there not LA springs.. they came with the heads when i bought them from some one.. i have to get the spring rates checked out
 
Assuming you are using the stock rocker arms ? believe it or not the pushrods from a boss 302 ford (like a 1970 model) are the same length as the one mopar sells.
 
Hello DusterBoy15;

A word of caution check your head to push rod clearance. I needed to
grind the area around the head partiing line. I recommend to install the
cylinder head on the block and before final assembly to check pushrod to
cylinder head clearance. Grind as needed.

I am using 1.6 rockers with the crane cams magnum guide plate system
and boss 302 push rods. Cycle the engine one rotation and check the push
rod and location of the rocker tip to valve stem relationship. The rocker
tip should be centered on the valve stem tip.

The heads are very efficent you won't need to push timing past 34 deg.
total. Depending on your combination as much initial timing as possible.

Denny
 
Dusterboy - to answer your question - I found out the length of the retrofit pushrods that mopar sells, and then cracked open an old erson cams parts catalog and looked for similar length pieces.

No big mystery ! What drove me to it was the fact a few years back when I was building a motor like this - the mopar pushrods were backordered and out of stock - so I did some digging around.

Where there's a will -
 
DusterBoy15 said:
look at these
http://cgi.ebay.com/ebaymotors/AMC-...012QQitemZ220194949014QQrdZ1QQsspagenameZWDVW
Click to expand...

Way to long, those are almost .2" longer than the conversion push rods.

The MP conversion push rods are cheap at $40 a set but tend to be a little short but you need to mock up th engine to now for sure. If the Boss 302 are the same length they will have the same issue.

I would get the push rod length checker and mock the engine up and see what you need. When you build an engine the last thing you should buy is the push rods.
 
i talked to a guy and he said that preload should be .30 to .60 so i think i will check but will get the ford 7.650 ones from comp cams
 
As far as cams go with using magnum heads and the 1.6 ratio rockers, it looks like the Comp Cams XE268H is about as big a lift cam that you can use without having to have some work done to the heads. That cam is built and rated for use with a 1.5 rocker ratio. The lift numbers of .477 intake and .480 exhaust are effectively changed to .509 intake and .512 exhaust. Anything under .525 should be ok... just be sure that you do the math to make sure!

Also... the longer exhaust duration (280) of that cam is good for scavenging the combustion chambers... more efficient, and potential for better mileage numbers. (if anyone cares about that)
 
umm im under .525 by .002 haha,but my heads have double springs so i have had machine work done already
 
Yeah... you will be maxed out. Gotta round the numbers up, so you will be at .521 intake and .524 exhaust.

Only .001 under the max recommended capability of the heads... I'd be scared to run that tight... add some heat to it (by running hard) and it could get easily damaged.

Be careful!
 
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