In this post you can see all the trouble that we went trough to connect the Thorley shorties to my exhaust. The bell housing had to be cut couple inches. If Thorley fixed the drivers side I would have no problem with them. http://mmb.maverick.to/showthread.php?p=999537#post999537
I am on my second set of Holly Flow Tech, FLT 12100 headers on my '74. They fit great. Ports match well. Easy install. As mentioned, low ground clearance. Mine is about 4 inches. I can't do speed bumps!!!
We used old Black Jack early 80's vintage (after the switch from square to triangle collector flange). they are for mustang fairlane maverick etc. they were pretty awful to install, atleast 7 times in and out, which means nearly full engine bolt-up and positioning each time. We centered the motor (it wasnt even close prior). then we adjusted from there. We still had to clearance for the steering on the driver side and shock tower on passenger. So in essence, there was nowhere else I could have positioned the motor side to side, and it hit on both sides. I have some photos on my profile, but not good enough shots to detail the clearance. They definitely DO NOT hang low, though.
Update: Hooker headers are installed finally! Had to get new motor mounts to lift the engine higher for some clearance and now i need to put notch in the driver side because the pitman arm is rubbing and i can only turn to the left slightly.
If you get Hooker 6901s and the power steering bracket, make sure to weld that power steering bracket. The nuts are not enough. Mine ripped off, tore my power steering hoses and sprayed fluid all over my driver side header tubes. The thing caught fire and I'm glad I was in a parking lot and not on the street.
I've heard of it happening and I totally agree, I would definitely weld it along with bolting it up because the added bracket adds leverage and an angle that causes vertical stress that wouldnt be there in stock form
be careful if you buy flowtech headers i put them on mine there are alot of clearance issues on the drivers side i had to put alot of dents in mine to get it to fit and its extremely close to the steering box... do they work? yes but it takes some work to get them to fit
FWIW...I ran Hooker 6901s on my car for years. But when I did the MII front suspension swap, there was no way they were going to fit around my larger 7 qt oil pan (all I could find at the time). So I bought a set of Hedman shorties, cut off the flange, and welded on a tube that angled it to where I wanted it to go, bypassing all the other components. When I ran it the first time on the way home from the muffler shop, it had WAY more low-end torque compared to the long tubes. I literally lost control of it coming out of my first turn from an intersection and spun the tires for about 1/8 mile once I got it straitened out. It never did that with the long tubes. And a BIG PLUS...They just stab right in from the top. No lifting the engine, loosening motor mounts, nothing. Just stab em in, and connect them to the rest of the exhaust. Here they are before I cleaned up the welds...