The driver-side header is a direct replacement. Because it bolts right onto the existing catalytic converter/downpipe assembly, installation took about 35 minutes. The passenger side, however, was another story altogether. Here, you need to modify the downpipe by cutting off the lead tube that goes to the front of the catalytic converter and weld the new Edelbrock tube into place. The purpose is to remove the tight radius of the factory downpipe that happens to be the most restrictive part of the exhaust system. Edelbrock also wants to gain additional clearance by the starter so it can fit longer primary tubes in the tighter confines of the passenger side.
Another time-consuming task here is the fitment of the gosh-awfully difficult-to-reach EGR feed tube that has a habit of refusing to line up. And when it finally is lined up, it'll take another leap year to get the one bolt that holds everything together into place and tightened. If it is this tough in a Caprice, we have a lot of sympathy for you F-body owners out there with an LT1. In total, the headers took us four hours to complete, but we were happy to find no leaks and excellent fit once everything was torqued down.
Back on the dyno, we were somewhat surprised to find no gain in power. Chris and I concluded that on a bone-stock LT1 the factory manifolds are still keeping up and are not a restriction at our power level. We didn't lose any output-the power curve overlapped our previous best within a few ponies, so we maintained our measurements of 261.3/353.2 at the wheels. Also, the headers were flowing into the restrictive stock catalytic converters, which negated any gains we might have had.
The good thing is, we are now ready for our future mods. The bad thing is, we've hit a wall as far as bolt-ons go, which in turn means that if we want more power, we'll have to either add a power adder of some sort or get into the motor. Truthfully, this is a perfectly fun car as it is, and we should stop here. But of course we're fools and will continue down the yellow brick road in our quest for more power and quicker timeslips.