I sold a bare set of those recently and took some pictures. They still were still pretty nice after sitting for 20 years. Never cleaned them. Barely any rust. This is how they looked after being used for testing.
Make sure it is seated square and the nuts or bolts are tightened evenly. If the flare on the pipe is damaged even slightly, it will not seal. As mentioned by WarWagon, high temp sealer can help.
GM gave the oil test facilities permission to purchase those heads directly from the manufacturer. GM had no use for them because the EGR and heat crossover was deleted. So technically they were never considered GM parts because they never went through their parts inventory system. The "BW" or...
Never knew they made an aluminum hood for the '78 Regal. I've seen the early '78-'80 aluminum Cutlass hood on a Regal. It fits but the body lines don't exactly line up with the header panel.
Yes, they work on a 4.1 intake and several of the aftermarket intakes with EGR also. Considering the EGR is on the back of the intake, you'll never see it anyway.
Not as fancy looking but these work just fine. I've personally dealt with this company and they are reputable and great to deal with. I have one of these sitting around also. TTA Performance