Greg studied the undercarriage,...
Greg studied the undercarriage, then used a piece of welding wire as a guide for the head pipe. He bent the wire to clear the oil filter and all of the other obstacles under the car.
Using the wire as a pattern,...
Using the wire as a pattern, he bent a long length of aluminized 2-1/2-inch-diameter pipe. The hydraulic pipe-bender makes easy work of it.
Greg held the pipe in place...
Greg held the pipe in place to check the fit. A long pipe was used because the mufflers will be located toward the rear of the chassis. Check out how the pipe gently bends around the oil filter.
Greg slipped a flange on the...
Greg slipped a flange on the pipe and attached it to the header. He adjusted the pipe to exactly where he wanted it, making sure it cleared the oil filter and transmission pan.
When the pipe was placed,...
When the pipe was placed, Greg tack-welded the flange to the pipe.
The pipe was removed and welded...
The pipe was removed and welded off the car, making it easier to weld the circumference of the pipe.
The other head pipe was made...
The other head pipe was made just like the first one and runs parallel under the car.
Both of the exhaust pipes...
Both of the exhaust pipes were secured by a hanger with a high-tech rubber insulator.
A crossover tube was added...
A crossover tube was added to the car with a flange in the center so the exhaust system could be separated side to side.
The crossover was angle-cut...
The crossover was angle-cut at the corner of the pipe, making it easier to weld in place.
After the crossover was set...
After the crossover was set in place, its tube diameter was marked on the pipes. Using the mark as a guide, holes were cut in the pipes for the balance tube.
The balance pipe was reinstalled...
The balance pipe was reinstalled over the holes and was tack-welded in place.
Greg finished welding the...
Greg finished welding the crossover pipe with a wire-feed welder.
Before the head pipes were...
Before the head pipes were made, Greg established where he wanted to mount the mufflers and tailpipes. There was a depression on the floorboard at the rear of the car that was perfect for the mufflers.
Greg used a special slip-over...
Greg used a special slip-over connection for the mufflers and tailpipes so that the system could be disassembled, if desired. The flare on the muffler side slips over the compressed area on the head pipe for a perfect gasketless seal.
Greg made the slip-over connection...
Greg made the slip-over connection on a separate length of pipe, then welded it to the muffler.
In this photo, Greg already...
In this photo, Greg already has one muffler in place and is trial-fitting the other one, making sure it lines up. This is muffler part number 52530.
The tailpipe, which came pre-bent...
The tailpipe, which came pre-bent from Flowmaster, exits over the axle with plenty of clearance and runs along the side of the gas tank with plenty of room to spare.
The tailpipes slip-fit into...
The tailpipes slip-fit into the mufflers, and when they were positioned correctly, Greg welded the two together.
Greg secured the muffler with...
Greg secured the muffler with a second hanger, which was welded to the body mount. The rubber hangers allow minimal exhaust-pipe movement.
A third hanger was used at...
A third hanger was used at the rear of the car and secures the tailpipe.
We selected chrome turn-down...
We selected chrome turn-down tips for the system that protrude outward about an inch. Greg kept the tips about 1/2 inch under the rear bumper.
The head pipes are tucked...
The head pipes are tucked up into the frame where they can't be seen from the side of the car and flow back parallel to each other with a crossover pipe located behind the rear trans mount. Two hangers secure the pipes and mufflers to the car in front of the rear axle.
This view shows the exhaust...
This view shows the exhaust system from the headpipes back to the mufflers with the tailpipes going up and over the axle assembly and exiting under the rear bumper. Notice that the system is parallel, and it's a straight shot from the engine to the tailpipes, which should be excellent for maximum engine performance. RC
When we started building the '57 Chevy, we already knew what type of exhaust system we wanted. That decision was made when we heard a friend's '55 Chevy with a Flowmaster exhaust system. It had a unique tone that turned heads as the car cruised through a car event, and the mufflers did a great job of accenting the engine's high-performance cam-shaft lope at idle.
Sounding good is important, but Flowmaster's mufflers are also very well-known for their performance benefits and are used on many drag race cars such as the NMCA/HRM Top 10 Street Car champions. The mufflers provide low dynamic backpressure, are fully aluminized inside and out, and feature fully welded construction. We selected a pair of mufflers with a 2-1/2-inch inlet and outlet diameter, and followed through with 2-1/2-inch aluminized pipe throughout the system. The tailpipes we used were already mandrel-bent and aluminized by the Flowmaster factory, so they were ready to install. The other pipes had to be fabricated, so we contacted Gene's Muffler Shop for a complete system.
Greg Coats at Gene's Muffler put the Chevy on the rack, studied the lower side of the car, and came up with a clean, simple design that would maximize the car's performance and would sound good, too. When he was finished, the exhaust system looked great and sounded just as good.