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1970-74 F-Body, Firebird/Trans Am, X-Body
Pontiac V8 1970-74 F-Body, Firebird/Trans Am, X-Body
Second-Gen, Sorted — 1970-74 F-Body, Firebird/Trans Am, X-Body for Pontiac V8s
The 1970-74 Firebird and Trans Am is the second-gen car before the bumper and floor changes, and it shares its exhaust family with the X-body Ventura. This is the widest F-body shelf Butler has, covering 2.5" and 3.0" systems, rear exit and quarter panel exit, with and without a crossover.
Everything here is Pypes Performance Exhaust: 16 gauge mandrel-bent 409 stainless, your choice of X-pipe, H-bomb H-pipe or no crossover, and Street Pro, Race Pro or Violator mufflers.
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More About 1970-74 F-Body, Firebird/Trans Am, X-Body
1. Know which second-gen car you have
This is where most ordering mistakes happen, and Pypes prints the answer in its own product notes.
| 1970-74 F-body and X-body | the core systems in this section are listed as fitting 70-74 GM F-body cars, which covers Firebird, Formula and Trans Am plus X-body Ventura. |
| 1967-69 cars | Pypes directs those owners to the first-gen crossflow and quarter exit part families instead. |
| 1975-81 cars | the late second-gen car takes its own X-pipe and H-pipe part numbers, which Pypes calls out by number in the 70-74 listings. |
2. Crossover and pipe size
| X-pipe, 2.5" or 3.0" | the largest group. 2.5" suits a rebuilt 400 or a strong street 455; 3.0" is for a big-cube build and is offered with quarter panel exit. |
| H-bomb H-pipe, 2.5" | the deeper note, in 409 stainless with your choice of the three mufflers. |
| No crossover | straight dual rear exit systems in 2.5" for owners who want the split note or a period-correct car. |
| Muffler-delete | every crossover style is also sold with no mufflers. |
3. Exit style and tips
Tips are separate, and on a second-gen car the tip choice also changes the tailpipe routing.
| Straighter out the back | Pypes notes that adding the optional EVT58 or EVT59 tip sets lets the tailpipes exit out the back straighter than the standard routing. |
| Trans Am splitters | running EVT10 splitter tips on a Trans Am requires the matching tailpipe adapter kit, which Pypes calls out by part number. Order both together or the splitters will not mount. |
| Quarter panel exit | offered on the 3.0" X-pipe systems for a more aggressive look behind the rear tire. |
4. What feeds the system
These systems pick up behind the crossmember, so what is ahead of that point is a separate decision that still changes your order.
| With full-length headers | a 1 3/4" D-port set on a second-gen car finishes in a 3" collector and a 1 7/8" round port set in a 3 1/2" collector. Confirm which you have so the downpipe connection is right. |
| With Ram Air manifolds | a stock-appearance car needs downpipes to reach the system, and a manifold with an oversized 2.5" outlet pairs naturally with a 2.5" system. |
| Do not oversize one end | 3.0" pipe behind restrictive factory outlets gains you noise and nothing else. Upgrade the front and the back of the path together. |
5. Picking a muffler
| Street Pro | the quiet end of the range, and the one to pick if the Trans Am does long drives. |
| Violator | the loud-but-livable middle, and the most common choice on a second-gen car. |
| Race Pro | the loudest, and available on the crossflow systems as two mufflers in a single transverse casing. |
All of these are 16 gauge mandrel-bent stainless, bolt together at home, and carry a limited lifetime warranty. If your car is lowered or running a wide rear tire, mention that when you call so we can steer you toward a routing that will actually clear.
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.