it sits right next to the battery, tees off at one point to a melted wire, and ends up at whatever that is. Do ineed it and what does it do? Thanks in advance.

I think it a vacuum reservoir/accumulator. I'd keep it.

I removed it on my cars and sealed the small hose.

Its number 5 in the first picture in the link below. That's part of the vacuum operated heat and ac control system. If you are keeping the stock dash and heater core, I wouldn't worry about keeping the control system and just manually adjust the valve inside the engine bay before sessions if you want the heat to circulate through the core. There's enough air movement when you're at speed on track to circulate through the system and keep the windshield from fogging as well as keep the driver nice and toasty in cold conditions.

www.clarks-garage.com/shop-manual/hvac-01.htm

The heater control valve is vacuum operated and located at the back of engine near the firewall. There is a vacuum line which goes from the valve to a vacuum connection at the firewall where the heater hose connections penetrate the firewall. Check this vacuum line to make sure it is connected and doesn't show any signs of cracking. There is another vacuum line fitting near the heater hose connections which goes to a rubber "Y" connector. One side of the "Y" goes to a small check valve attached to the large brake booster vacuum line at the back of the firewall. The other side of the "Y" goes through the firewall to a plastic vacuum retention canister next to the battery.

it is an early vacuum reservoir for the A/C system. If you are keeping the A/C, you will need it. Otherwise, it can be disposed of.

It's basically "holding vacuum" so that the flaps in the heater box in the passenger compartment remain open (they are held by vacuum) in all throttle conditions.

Thanks for the help guyd. I'm removing all the a/c stuff so its going to go. I do like that idea about manually adjusting it before a race, what parts would I need to keep to keep that option?