I was going to create a "Phase II" thread, but I thought I'd keep everything together and in one place for anyone's future reference. If you haven't taken a peek at page 1 of this thread, you are better served to start there.
This update will cover the fabrication work on the pipes. Here is how everything looked after I pulled the stock (and ceramic coated) Superformance side pipes from #747:
As you can see, the Stainless Specialties custom mufflers were built to exacting specifications, with exception to my requirement to add one (1) inch of length to the case. As was discussed prior in this thread, this was done so that the fabricator had enough material to work with to maintain the exact length of the entire assembly from the collector to the tip of the tail pipe.
Here is an "after" shot of the side pipes once Alex Mikkelson of American Roadster (Placentia, CA) did his magic. I laid a factory muffler beside them for reference:
Alex is a pro, having done all the chassis work on the recently restored BankAmericar front-engine top fuel dragster. He also did all the chassis work on the Hot Rod eBay rail dragster (both cars were heavily featured in the magazine). Alex's attention to detail was incredible, as he built a temporary jig out of scrap tubing and spot welded it right to his work bench! This allowed him to match all of the correct angles, lengths and attachment points (especially for the side bracket, which had to be dead spot on). Alex got $250 for his efforts and I was more than pleased with the work. Word to the wise:
Muffler shops can't handle this type of work. If you are not an advanced welder, then farm out the work to someone that knows what they are doing.
I did a quick reassemble to ensure everything was true and both sides bolted up with hardly much effort (driver side was too easy and the passenger side was maybe 1/16" off...a little coaxing got the side bracket to match up). Unfortunately, I did all this in the wee hours of the morning and couldn't fire it up.. So I tore it back down and that same day sent the pipes out to Embee Coatings in Santa Ana for a fresh ceramic coating (just as before). Embee gets $300 plus tax for their efforts.
I will get the pipes back in roughly two weeks time, in which I will then report on the sound and performance. "Eric" has another thread going on right now in which he has performed a near-identical modification to a similarly configured (stroked Windsor) Superformance. He's reporting over 20HP and 18FtLbs improvement with just minor jet tweaking (to compensate for the lean condition that the better breathing will cause). "Karl" is another CC member that did this exact same mod on a 514CI Superformance. He says they sound "crisp", certainly louder than stock, and the seat-of-the-pants performance increase is a seat wetter! Woohoo!
Stay tuned for the final chapter on this whole odyssey, which has cost me about $950 once you add in some new gaskets and all new grade 8 fasteners for the flanges. Some may say that this is a lot to spend for arguably a 20HP increase. Consider two factors. (1) The factory headers are not Hooker Super Comp quality, so those will eventually go next, and (2)
I was after a much more aggressive sound versus achieving the power increase (which was obviously going to occur).
-Dean (now going through the tool box looking for some ear plugs
)