My garage is soundproofed. Only poor souls that will be hearing my obscenities are my dear old dogs!
, I was awaiting your response as we have similar builds.
When you attempted the install, was your frame setup similar to mine? When I get around to it tonight I'll go through a dry run and see if the headers hit frame/suspension.
There's a video
FMG had to make some dents on the tubes for fitment, but every car is different so wish me luck
Good Vid. I never had those kind of clearance issues on any 67 install. Except the brake block that is common and the control arms /a frame tops. Solved with torch, prybar and hammer. Possibly slightly tighter on 68-72 due to shorter W.B. I also noticed you have after market tubular control arms. They appear to have a good 1/2 to 1" additional clearance.( you may not have an A arm issue at all do to this) Assuming these are 1 & 3/4" tube headers, when you get them mounted on the engine, you will notice the tubes & collectors taper down low slightly inside the cylinder head on pass side and slightly outside width of cylinder head on D side to allow more clearance for starter & clutch actuation assembly.
If You're mounting engine with headers with some sort of cherry picker, you may need to tilt the motor and trans assembly down in the rear. You may also have to tilt D - side of engine down due to header protruding out slightly wider than head on that side. But you can also move trans crossmember for more room if needed. Can't see how this wouldn't be the easiest way to do it.
The real beauty of this is if we're wrong, you simply take the headers off, drop the engine in and do it the typical hard way from underneath on the ground or if you have a hoist, strap the front frame rails down so when you lift the engine a few inches to clear, the car doesn't slide off the hoist.
I should also say that after many years of header installs and dyno tests with headers compared to RA manifolds, I am more a proponent of the RA manifolds for over all sealing and performance on a mild build that is. Either way, If you're choosing headers on a high perf build or just simply cool factor, hats off to you.