how to install headers?

I’ve installed just about every kind of header made on small block A-bodies. They are all a real pain to install. TTIs are a little easier than others but, even with them, the job is far from easy.
Disconnect the battery. If you drop a socket between the starter’s positive post and a ground, you will have a major short on your hands. Don’t ask me how I know.
Drain the coolant first. This includes draining the block as well. If you don’t drain the block you will end up with coolant everywhere once you remove the front and rear exhaust studs.
Get the front end of the car up as high as you can and securely support it.
Drop the center link.
Drop the down pipes off the exhaust manifolds.
Pull the starter.
Remove the manifolds.
Remove the distributor.
Jack up the engine as far as you can but pay attention that you don’t pinch or bend anything.
Take a break.
Clean the gasket surfaces on the heads.
The passenger side header typically goes in from the bottom. Just install the front and rear bolts and leave the headers loose.
Now for the fun part, the driver side. If you’re using TTIs, #7 tube is a slip fit. The other three tubes go in from the bottom. Hang them by the front bolt only.
Slip #7 tube in from the top. It helps to put a little anti-seize on the tube to help it slip into the rest of the header.
Snug all the bolts but don’t torque them yet.
Put the starter back on.
Reinstall the center link.
Slowly lower the engine making sure you don’t get the headers in a bind.
Take another break.
Tighten the header bolts using Loctite with Teflon on the front and rear header bolts.
Put the distributor back in.
Fill the engine with fresh coolant and fire that mother up!
Make sure you check your plugs. You’ll probably have to richen the carb up a bit.