Where to buy GM Pushrods 144mm ?

[TexasGuy]

I have a problem, I want to do a valve job on my '95 Chevy Lumina APV (van) 3.1L but I cannot find a cheap source of pushrods.

Here is a problem, all aftermarket stores have only one SKU for the pushrods in my engine. However, it has 2 kinds (intake and exhaust), different length, 152mm and 144mm. I cannot find 144mm anywhere but GM dealer part store with $13 a pop. Kind of an overkill for my antique van.

Also, the 152mm one, the one that aftermarket stores have a sku on (like AUTOZONE, ADVANCED AUTOPARTS, NAPA etc) they have a push rod that is about 4mm longer than from GM dealer, the 152mm one. I think everyone wants me to buy 156mm one which is will probably junk the engine. Seems like a stupid conspiracy on a simple old car...

What can I do? I don't want to buy $130 worth in rods that to GM cost like 25 cents each to make, no wonder they are in a financial hole. Plus, I don't like to be had.

So, can you suggest some on-line or other way to get the proper pushrods at the price that I can afford to invest in a 14 year old car?

GM parts: 10166355 (green), 10166354 (yellow)