71 340 Compression Test

Your cylinder pressure is indicating around 10.2Scr. With the stock 268/276/114 cam with an ICA of 66* your Dcr comes in at around 8.00
This puts you near the limit of pump-gas. And near the limit of cam sizing. A bigger cam will likely require a bigger TC and 3.55s or better, to overcome a softening bottom end, unless your Scr is increased to keep pace. So you are kindof in an all-or-nothing situation. The all being; engine,TC,and gears,until the tranny gives up at least..... Of course the increased power will require more traction,cuz what's the sense of spinning all the way to 60 or more mph. Thankfully the Barracuda will accept 295s no problem. Well except for moving the springs, and either custom 10 inch wheels or a narrowed rear, or both.Of course the beast still won't hook,so now you are looking at springs,shocks,and possibly,traction aides. Finally it hooks, but now she's getting some serious speed in a hurry, and you find out the stock suspension and brakes are not adequate.
Long story short is this; $8300 is just the down payment.
Don't get me wrong; I'm all for 400 hp. The 67 to 69 Barracuda can be an excellent chassis for 400 hp, but I just wanted to shine some light on the road you are going down, having made the trip myself. In Canada, back in the early 2000s, it was easy to spend $16,000Can on the full deal. Not including original purchase price, or paint and body repairs.Just upgrades.
No wonder I'm broke today........