340 pushrod problem

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christmas53

FABO Gold Member
FABO Gold Member
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The pushrods in my 340 are hitting the roller rockers. The ones in it now are 7.5" long.
 
I had a adjustment screw brake and a pushrod broke too. When I pulled the shaft and rockers you can see where some are hitting.
 
Sounds like you need some shorter pushrods so you can run the adjusters down a little to keep the pushrod cups away from the rocker arm.
 
where the rockers hitting the pushrod or are they hitting the retainers?
 
The cup part of the rod is hitting where the Allen adjuster comes thru the rocker
 
340 T/A pushrods are 7.572 OAL (SP RP3159). 273 solids are 7.658 OAL including cup (SP RP3107). Solid lifters are deeper than hydros so that explains the difference. I got some pulls that measure a little over 7 3/8 that fit fine on Crane rollers and a .484 MP hydro cam. Your measurements will differ as rockers and lifters are not standardized across manufacturers. Best bet is to mock it up and measure, then have them made if they are radically different than stocked pushrods. I hear 2 threads out is correct on adjustables but its a builders call. Crane makes cup style adjusters too so you can run cheaper ball/ball pushrods. Can you shim your rocker shafts? You can make your own custom pushrods.... Cut down 16 slant six pushrods. http://www.forabodiesonly.com/mopar/showthread.php?t=297318
 
Pishta,, The method of removing the ball from the pushrod tube and shortening the tube works with (some) after-market pushrods as well,, only the ones I've trimmed weren't welded,, just friction fit.. so by putting the hardened ball in a vise,, and just a few seconds of propane heat on the tube,, twist and pull..
 
what ratio rockers? 1.5 or 1.6? the 1.6 will throw all the geometry off and the pushrods will hit the galley hole and rocker especially if you have 7.5 inch rods, the need to be the 7.38 inch rods so you have more adjustment screw sticking out/down out of your rocker
 
... the need to be the 7.38 inch rods so you have more adjustment screw sticking out/down out of your rocker....
Those are the ones I got. Sounded short when I looked a the mic but they work.
 
that is weird, i got two engines with 7.50 pushrods...1.6 crane rockers...with the correct number of threads showing...nothing rubbing...one set is 5/16 and the other is 3/8 ......
 
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