Uploaded November 2024 | Updated September 2026, 2 weeks ago
This video features the installation of a Pypes 3 inch 409 stainless steel Pro Street Exhaust System with Street Pro mufflers into my 1971 Oldsmobile Cutlass S. The car is getting a new big block Olds in 2025. I got a deal I couldn't pass up on a pair of 1-3/4" primary headers, so off come the manifolds, and on go a pair of headers too!
0:23 What is 409 stainless vs 304 stainless?
1:04 Showing the exhaust cutouts & why I didn't like the fasteners for them
2:23 Why I didn't like the clamps the Pypes kit came with, and a couple of alternatives
3:43 The "Street Pro" stainless steel mufflers are actually in the middle as far as loudness. Apparently the "Race Pro" mufflers are the quietest, and the "Violator" mufflers are the loudest
4:03 My kit had no instructions
4:24 Tip: the arrow points towards the FRONT of the car
4:42 How far apart are the collectors of American Racing 2" primary A-body headers on a big block Olds? (I have a mockup) - mine was 21-1/16" apart center to center. The Pypes exhaust was 21-5/8" center to center without any cutting.
6:04 Lay the system out on the floor first and start at the back of the car
6:24 Showing mounting the tail pipes
6:46 Showing the tail pipes with my 275/40ZR18 tires mounted on the
Vision American Muscle 143 Torque Series Gunmetal Wheels 143-8961GMML12 18"x9.5" wheels with 5.75" back spacing
7:54 Showing the details of the M8x1.25 bolts that came with the kit for the cutouts. I used 3/8" x 1" long stainless steel bolts with stainless lockwashers and nuts instead.
8:22 I have another gripe: why I didn't use the 5/16" sheet metal screws provided in the kit to mount the exhaust hangers to the frame. I used P/N 80797 5/16" x 3/4" long Hex Washer Head Sheet Metal Screws Type B from Menards instead
9:25 How the Pypes hangers for the mufflers are arranged and installed, and a tip I got from my friend Ken to improve the ability to assemble and disassemble the system
10:52 Showin the factory holes in the frame crossmember used to mount the muffler/tailpipe hangers
11:54 Showing the holes in the rear of the frame rails to mount the tailpipe hangers provided in the kit
13:23 My mufflers have clearance issues with my UMI Performance Control Arm Reinforcement Brace Kit 4028-B
13:53 Using the Pythagorean Theorem to figure out how much to shorten the 45° leg (A² + B² = C²). If I shorten a 45° leg by 1.06", the pipe should move in 3/4"
14:45 showing more tailpipe fitment issues with the shock absorbers
16:30 connecting the pipes going into the X pipe to the iron manifolds
19:33 Cutting an inspection cover ear completely off of my new 4L80E transmission to be able to bolt on the 3 bolt flange
20:22 I found a bunghole in the passenger side exhaust manifold (I was NOT able to get the plug out)
20:50 Making a nice passenger side downpipe with an oxygen sensor bung to connect the 350 iron exhaust manifolds to the 3" Pypes head pipes
22:07 Welding up a new larger downpipe 2-1/4 to 2-1/2 to 3" for the driver side
23:55 Showing the mandrel bent downpipes I made and how they fit
25:05 System "finished" with iron exhaust manifolds
25:56 FlowtTech 1-3/4" primary chrome plated headers & installing them
26:57 Modifying the pass side header
31:08 Using 3" flex pipe to connect the headers
32:28 The finished result and my opinion of the Pypes system
33:40 The old vs new exhaust
The Pypes Street Pro Exhaust Systems SGA14S headers:
summitracing.com/parts/PYE-SGA14S
Instructions for it:
static.summitracing.com/global/images/instructions/pye-sga10-sga11-sga12-sga13-sga14-sga16.pdf
Summit Racing™ Band Clamps SUM-692030 (3" stainless, these better allow you to be able to take the exhaust back apart):
summitracing.com/parts/SUM-692030
Walker Universal Ball Flanges 41725 for the original downpipes:
summitracing.com/parts/WLK-41725
The AP Exhaust 3" ID in - 3"ID out Flex Couplings 8854:
summitracing.com/parts/APH-8854
I purchased 1 from Summit Racing & 1 from O'Reilly Auto bc both places only had 1 in stock. Nickson 3 Inch Stainless Steel Flex Tube - 01948:
oreillyauto.com/detail/c/nickson/nickson-3-inch-stainless-steel-flex-tube/nic0/01948/v/a/16510/automotive-car-1971-oldsmobile-cutlass?q=3%22+exhaust+flex+coupling&pos=0
Note: the Nickson one only has one layer of mesh on the body, where the AP one had a corrugated pipe covered in mesh. The AP one seems more durable and less leak prone.
Here are the creamic coated version of what I got: Flowtech Headers 31150FLT (1-3/4" primary, 3" collector):
summitracing.com/parts/big-31150flt/make/oldsmobile/model/cutlass/year/1971
Here are the cheaper plain steel version: Flowtech Headers 11150FLT:
summitracing.com/parts/big-11150flt/make/oldsmobile/model/cutlass/year/1971
These are the American Racing 304 stainless steel 2" primary, 3.5" merge collector headers:
summitracing.com/parts/AMH-S00598
This video features the installation of a Pypes 3 inch 409 stainless steel Pro Street Exhaust System with Street Pro mufflers into my 1971 Oldsmobile Cutlass S. The car is getting a new big block Olds in 2025. I got a deal I couldn't pass up on a pair of 1-3/4" primary headers, so off come the manifolds, and on go a pair of headers too!
0:23 What is 409 stainless vs 304 stainless?
1:04 Showing the exhaust cutouts & why I didn't like the fasteners for them
2:23 Why I didn't like the clamps the Pypes kit came with, and a couple of alternatives
3:43 The "Street Pro" stainless steel mufflers are actually in the middle as far as loudness. Apparently the "Race Pro" mufflers are the quietest, and the "Violator" mufflers are the loudest
4:03 My kit had no instructions
4:24 Tip: the arrow points towards the FRONT of the car
4:42 How far apart are the collectors of American Racing 2" primary A-body headers on a big block Olds? (I have a mockup) - mine was 21-1/16" apart center to center. The Pypes exhaust was 21-5/8" center to center without any cutting.
6:04 Lay the system out on the floor first and start at the back of the car
6:24 Showing mounting the tail pipes
6:46 Showing the tail pipes with my 275/40ZR18 tires mounted on the
Vision American Muscle 143 Torque Series Gunmetal Wheels 143-8961GMML12 18"x9.5" wheels with 5.75" back spacing
7:54 Showing the details of the M8x1.25 bolts that came with the kit for the cutouts. I used 3/8" x 1" long stainless steel bolts with stainless lockwashers and nuts instead.
8:22 I have another gripe: why I didn't use the 5/16" sheet metal screws provided in the kit to mount the exhaust hangers to the frame. I used P/N 80797 5/16" x 3/4" long Hex Washer Head Sheet Metal Screws Type B from Menards instead
9:25 How the Pypes hangers for the mufflers are arranged and installed, and a tip I got from my friend Ken to improve the ability to assemble and disassemble the system
10:52 Showin the factory holes in the frame crossmember used to mount the muffler/tailpipe hangers
11:54 Showing the holes in the rear of the frame rails to mount the tailpipe hangers provided in the kit
13:23 My mufflers have clearance issues with my UMI Performance Control Arm Reinforcement Brace Kit 4028-B
13:53 Using the Pythagorean Theorem to figure out how much to shorten the 45° leg (A² + B² = C²). If I shorten a 45° leg by 1.06", the pipe should move in 3/4"
14:45 showing more tailpipe fitment issues with the shock absorbers
16:30 connecting the pipes going into the X pipe to the iron manifolds
19:33 Cutting an inspection cover ear completely off of my new 4L80E transmission to be able to bolt on the 3 bolt flange
20:22 I found a bunghole in the passenger side exhaust manifold (I was NOT able to get the plug out)
20:50 Making a nice passenger side downpipe with an oxygen sensor bung to connect the 350 iron exhaust manifolds to the 3" Pypes head pipes
22:07 Welding up a new larger downpipe 2-1/4 to 2-1/2 to 3" for the driver side
23:55 Showing the mandrel bent downpipes I made and how they fit
25:05 System "finished" with iron exhaust manifolds
25:56 FlowtTech 1-3/4" primary chrome plated headers & installing them
26:57 Modifying the pass side header
31:08 Using 3" flex pipe to connect the headers
32:28 The finished result and my opinion of the Pypes system
33:40 The old vs new exhaust
The Pypes Street Pro Exhaust Systems SGA14S headers:
summitracing.com/parts/PYE-SGA14S
Instructions for it:
static.summitracing.com/global/images/instructions/pye-sga10-sga11-sga12-sga13-sga14-sga16.pdf
Summit Racing™ Band Clamps SUM-692030 (3" stainless, these better allow you to be able to take the exhaust back apart):
summitracing.com/parts/SUM-692030
Walker Universal Ball Flanges 41725 for the original downpipes:
summitracing.com/parts/WLK-41725
The AP Exhaust 3" ID in - 3"ID out Flex Couplings 8854:
summitracing.com/parts/APH-8854
I purchased 1 from Summit Racing & 1 from O'Reilly Auto bc both places only had 1 in stock. Nickson 3 Inch Stainless Steel Flex Tube - 01948:
oreillyauto.com/detail/c/nickson/nickson-3-inch-stainless-steel-flex-tube/nic0/01948/v/a/16510/automotive-car-1971-oldsmobile-cutlass?q=3%22+exhaust+flex+coupling&pos=0
Note: the Nickson one only has one layer of mesh on the body, where the AP one had a corrugated pipe covered in mesh. The AP one seems more durable and less leak prone.
Here are the creamic coated version of what I got: Flowtech Headers 31150FLT (1-3/4" primary, 3" collector):
summitracing.com/parts/big-31150flt/make/oldsmobile/model/cutlass/year/1971
Here are the cheaper plain steel version: Flowtech Headers 11150FLT:
summitracing.com/parts/big-11150flt/make/oldsmobile/model/cutlass/year/1971
These are the American Racing 304 stainless steel 2" primary, 3.5" merge collector headers:
summitracing.com/parts/AMH-S00598
