I have a 1968 Camaro with a big block (454) and exhaust manifolds. I want to install headers but first would like some help with the best and easiest way to get the headers to fit (can it be done without the engine coming out).

Are you using the big block frame mounts for the 454? Does the car have power steering? ac? these factor in to header fitment on the car.

On my 68, without ac and no power steering, I used the Hedman ceramic coated headers and they were pretty easy to install. I had to dimple the passenger floor pan about 1/8" to clear the flange but had no other problems.

The passenger header fit from the top of the engine. The driver's side was put in from under the car. I had to raise the front about 36" to get it in.

If you can afford it, the ceramic coated ones are worth the extra expense. The underhood temps are much lower and they don't have to be painted every year.

I have a 68 with a 396 and powersteering. The headers will have a "notch" taken out of them for the pw/str. I about to change my headers but haven't yet but talked with a guy with a 68, BB, powersteering that changed his headers, he said you have to lift the engine a little and slide the headers up from the bottem the lower the engine and connect. This is what I have heard and intend to do but I can vouch for it 100% as I haven't done it yet....

Yep, lift the engine a little, drop'em out the bottom. It helps if the car is jacked up a bit so you can angle the headers down a little, too.