suggestions for my 340?

I didn't read most of rumble's post-- but I'm positive his advice is sound . You need to assist us with more detailed info-- you don't know what gears you have not sure about the engine-- but you want to go faster. That is one vague & expensive statement.

You need to find out what your car has in it, & then do some searches on this site-- lot of info already posted.

Your engine compartment looks clean-- shoot, I'm off today, bring it to Wichita Ks & I'll look it over(engine size/ rear end ratio, exhaust size)) & test drive it!! Then you can have a baseline for improvement.

for that matter take it to a local track, run it in the 1/4 mile & that would give everyone a baseline performance of this car. Lawrence