I have to order an odd length pushrod for my setup. I've found what I need, but it's in 3/8" instead of 5/16". I know the hole in the heads is 0.43 so it would fit.....but would it work?

 

Probably will depend on what other parts you are using with the valve train. Which rockers are you planning to use?

 

3/8 " are much stiffer than 5/16" of same wall thickness, and are used on aggressive/high lift/high rpm engines. If you make sure it clears everything it should work, but I'm surprised you can't find a 5/16" of the correct length. What length do you need?

 

I need 7.675 length. My heads are the LS6 style with Crane dual springs. I am setting up the stock rockers until I can afford to go to adj. shaft mount. I can get custom rods made, but it would be easier to order a stock item. I haven't found anyone with this length in the 5/16".

 

I found some 5/16" in the length I need from Trend Industries....great place.