1955-1957 Chevy LS Exhaust Accessories

Exhaust hardware for an LS swapped 1955, 1956 or 1957 Chevy, the Tri-Five Bel Air, 210, 150 and Nomad. The list is short and practical: stainless band clamps sized 2-1/2 and 3 inch, a 3 to 2-1/2 inch cone reducer set, a 3 inch band clamp with an O2 sensor port, and stainless steel header bolts.

2-1/2 and 3 inch clamp sizes
Reducers sold as a set
Stainless header bolts

The 1-7/8 inch long tube and mid-length Tri-Five headers, the cast iron LS manifolds, mounts and crossmember are on the 1955-1957 Chevy LS swap page. Browse all BRP exhaust parts under exhaust components.

1955-1957 Chevy LS exhaust accessories

Tri-Five pipe joints

O2 sensor clamp and header bolts

Tri-Five exhaust, part by part

Joining 2-1/2 inch tubing: 2-1/2 inch band clamp
Joining 3 inch tubing: 3 inch band clamp
Going from 3 inch down to 2-1/2 inch: reducer set
O2 sensor on a 3 inch section: O2 band clamp

1955-1957 Chevy swap notes near the exhaust

BRP long tube headers for these cars end in 3 inch V-band collectors, per the product description.
The guide says the Tri-Five kit is built for the Moroso high clearance pan, or an LH8 pan trimmed to clear the frame.
Low mount LS A/C compressors do not clear the 1955-1957 frame; the guide points to a bracket that moves the compressor up top.
With a T-56, the body seam inside the transmission tunnel gets flattened before the engine goes in.

Notes from the 1955-1957 Chevy LS install guide and the long tube header listing. Part sizes come from the product names.

1955-1957 Chevy LS exhaust FAQ

Which headers does BRP offer for a 1957 Chevy LS swap?

There are 1-7/8 inch ceramic coated long tube and mid-length headers for 1955-1957 Chevy cars on the parent swap page. This page carries the clamps, reducers and bolts that go with them.

Do the Tri-Five long tube headers come with bolts?

The long tube header listing includes header bolts, gaskets, collector extensions and V-band clamps. The stainless bolts here are sold separately for other builds or spares.

Can I keep a low mount A/C compressor on my 55-57 Chevy LS?

No. The guide says low mount LS compressors do not clear the frame, so the compressor has to be relocated to a top mount bracket.

What steps a 3 inch pipe down to 2-1/2 inch on a Bel Air?

The 3 to 2-1/2 inch cone reducer set. Clamp each end with the band clamp that matches the pipe size.