360 push rod dilemma

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jethomas15210

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I recently purchased a pretty nice street worthy 73 Dodge Dart Sport. Used to own a couple back in my teens. I started to repair a head gasket leak but instead decide to pull the engine to to do a paint job which has now turned into a complete engine overhaul thus opening up the dreaded can of worms. I know nothing about this engine other than its a 72 360 which I believe is pretty standard. It has had replacement CAM with hydraulic lifters however its a mystery to the exact make or model. Upon taking it apart I found one of the pushrods slightly bent. What I thought was going to be a easy fix has now turned into a search and rescue mission. The pushrods are not your standard 3/16" diameter pushrods they are solid 9/32" diameter rods with dome ends. As you can see in the attached photo they also have a strange 7.480" length. I have searched most major restoration parts sites and have stuck out. Does anybody have a clue where I might be able to locate some 9/32" diameter replacement pushrods? Thank you

20240307_174100.jpg
 
Smith Bros, Manton, Trend, Comp cams, all will make you whatever you need. And you could likely find an off the shelf pushrod that will work at summit racing or jegs.
 
Sorry I miss spoke in my previous thread, I meant 5/16 not 3/16. All the ones at Summit and JEGS that I have found are 5/16". I haven't found any 9/32". I'll look into the other places you suggested. I was thinking about replacing them with 5/16" ones but I think I'll need to then buy new rocker arms. I have a 5/16 ball end rod but I'm not sure its seating all the way in the receiving dimple on the rocker arm. Thanks
 
Isn’t the stock LA pushrod 5/16”? What am I missing here? What rocker arms are you using?
 
You are correct hence the issue. All the rods in this one are 9/32". The only markings on the rocker arms is shown in the photo. Another mystery, a few of the rocker arm springs have spacers under them.

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Click to expand...
 
Step up to the larger size and forget about it.
 
I found some info (online for whatever that’s worth) that some small blocks, 318, 273, and some 360 had .28 diameter pushrods from the factory. I have to say Ive never measured a stock one to know but I guess it’s possible. I have a stock 72 318 I could measure if I get curious enough. But I agree with above, order 5/16 in the length you need and move on. You have the stock paddle type rockers which will be fine
 
If the cam has increased duration, that means more rpm. More rpm makes lifter pump up more possible.....& a thin, weak prod bending.
I did not know these engines had pathetic 9/32" prods. Strange, because Mother usually makes everything extra strong...
 
I have a bunch of factory push rods, I can check if you want me to. I have used 5/16 and 3/8 diameter already. I have removed some out of 318 engines, that I thought were pretty skinny, but I haven’t measured them
 
I believe the lengths are measured as if the ball end was completely round. those have a slight flat at the ends which probably account for the missing .020" put set of stockers in it and send it.
 
Is there any witness marks on the valves or piston for that cylinder? If not, you might have had a sticky valve. If you are building it, time to get a cheap degree wheel/dial indicator/piston stop. Cheap set of calipers. Measure everything, that way if you get it running and there is an issue you will know what you can eliminate from the possible causes.
 
Thanks to all for your help. I've decided to upgrade to the standard 5/16" x 7.5" prods. No marks on the pistons however the cylinders are worn so I'm having it bored to 40 over. I haven't started the rebuild yet but I do find it interesting that all the exhaust side valve springs have spacers under them. I 'll measure the installed height once I do the assemble to confirm they are needed.
 
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