Is there a difference between a 7 speed chain and an 8 speed chain other than initial length? Can an 8 speed chain be used on a 7 speed bike by simply removing enough links to give it the same length as the chain I would be replacing? Any other useful chain info would be appreciated thanks guys.

The length has nothing to do with the number of "speeds".
It's determined by the size of the largest chain ring, largest cog and the distance between them.

6-8 speed chains are the same WIDTH! They get progressively thinner for 9 & 10 speed.

SO, in sum the 8 speed chain would work fine for a 7 speed cassette but a 9 or 10 speed one would be to thin? Would a 10 speed chain work for a 9 speed cassette or vice versa?

The "thinness" of the 9 speed is in the thickness of the side plates.

Recently, I was using a 9 speed chain with cranks from an early 70's 10 speed road bike (2X5).

You CAN NOT use 9 speed chain on a 10 speed cassette or 8 speed chain on a 9 speed cassette because the chain is too wide and doesn't fit between the cogs without rubbing.

You CAN use your 8 speed chain on a 7 speed cassette no problem! You do have to have the chain sized to the proper LENGTH for ANY combination.

https://www.parktool.com/blog/repair-...-length-sizing

You can use a thinner (higher speed) chain, but there's no point. Chains got narrower beginning with 9-, then 10-, etc.

That said, 8-speed and lower uses the same exact chain, so whether it's labeled as 7-speed or 8-speed, they're all 5/6/7/8-speed.

If you want to check the length, parktools have three different methods that all give the same result.

Thanks for the input guys earlier today I went to a lbs that is closing and picked up an 8 speed sram pc-830 chain and installed it before work. I didn't have a chance to ride it but it seemed like it glided like butter.