[RockBit]

I did more investigation on the length of the exhaust system in order to understand the difference between the two sides.

I measured the overall length of both sides. Passenger side is 52 7/8 and driver side is 52 1/4, so the passenger side is 5/8 inches longer. This does not explain the difference in proximity to the rear tire (passenger side is 1 3/4 closer).

The passenger side cylinder head is 1 inch forward as compared to the driver side. This is the connecting rod offset.

The passenger side pipes exit the body of the car 20 inches behind the center of the front wheel. The driver side pipes exit the body 19 inches behind the center of the front wheel. This means that the primary headers on the passenger side have a 2 inch aftward bias built in as compared to the driver side.

The aftward bias on the passenger side of the primaries explains 1 inch of the difference in proximity to the rear wheel. That leaves 3/4 inches to be explained. On my car, the exhaust exit (past the baffle) is 1/2 longer on the passenger side as compared to the driver side, leaving only 1/4 inch difference. This 1/4 inch is probably within my measurement error.

So, to get the pipes perfectly symmetrical, one would have to remake the primaries to move the passenger side exit forward by an inch, and then shorten the exit section on the passenger side by 1/2 inch.

Remaking the primaries on one side is too much trouble to me, and the offset in them may be there for a reason. This extra inch could also be taken out the of length ahead of the collector. If I were having new side pipes made, I would just make sure the exit section is the same on both sides and call it good.