Best 416 small block, 727 auto, TTI installation order?

Make sure you have your transmission lines figured out before you drop that all in there. Reproduciton trans lines will not route correctly around those headers. You will need something custom to make it work. You do not want to be under that car figuring it out once the drive train is in place. TTI should add info on trans cooler lines to their instructions.

I dropped my engine/trans in then put headers in from the bottom. You will have to have steering linkage out of the way. Jacking rear of car up helps a lot. I used a lift plate that bolts to carb which causes engine to tilt way back when trans is bolted up. Then I have a floor jack under car facing front to rear that I line up with trans tail shaft once I lowered it down. The jack on the trans drive shaft keeps trans from scraping the floor and helps level out the engine trans as you lower it down.

I never tried just laying the headers in place but with steering linkage, starter, and oil filter out of the way those TTIs aren't real hard to get up in there.

And like mentioned above put a lot of blankets and towels over all that fresh paint as you drop it in and while bolting everything up.

That engine compartment looks outstanding!! That is gonna be one killer ride!!!