Headers assembled fit
I've run an SLP hi-flow Y-pipe since I started mod'ing my stock 305. It flowed well and I later added the 3" SLP SS cat-back system. Additionally I did some minor porting on the stock iron exhaust manifolds when I installed the ZZ4 motor, to gasket match the taller `D'-shaped exhaust ports of the Aluminum L98 heads.
I've been very satisfied with SLP's engineering/quality so after deciding to move up to headers, I tried to get a set of the Tri-Y's only to find them discontinued and sold-out. I then re-ordered the 4-to-1 set in the 1-3/4" size, with AIR tubes to keep emissions compliant. I decided on the SS headers over the ceramic coated ones as I like the SS aging looks, and I can't cost justify the coatings.. (IMHO, YMMV).
I'm planning on getting/installing a Random Tech. performance Catalytic Converter at the same time as the headers go on to maximize the exhaust flow from the headers, into the cat-back..
Click on any image below for an enlargement (~500K) image.
Header port height measured (40mm)
Header port height measured (40mm)
Header port width measured (32mm)
Header port width measured (32mm)
Header primary tube measured (1 3/4")
Header collector tube measured (2 1/4")
Header cat. (join-up) tube measured (3")
SLP y-pipe and Cat. removed from car. Shown with part of header y-pipe
Closeup of "carbon" gasket ridge on head. (gasket larger than exh port...)
D-side header shown with manifold removed
Exh Manifold port height. (was gasketmatch ported to `D'-shape head already) (41mm)
Exh Manifold port width. (was gasketmatch ported to `D'-shape head already) (35mm)
Exh Manifold collector measured. (2-1/8")
Drivers Side header rubbing/resting on steering column !
Drivers Side header rubbing/resting on steering column !
Passenger Side header in place (not bolted)
Drivers Side header dented for steering column clearance (as per SLP)
Drivers Side header dented for steering column clearance (as per SLP)
Drivers Side header dented and installed
Y-pipe installed (w/o cat adaptor)
Cherry picker used to tilt motor for D-side header install.
CATCO Inlet (inlet walls shroud in to round neck)
CATCO inlet measured (2-1/2" round)
CATCO core width (4-1/2")
RANDOM core width (6")
CATCO Volume of core catalyst block is 67.5 cubic inches
CATCO neck flow area is 19.635 square inches
RANDOM inlet measured (3-1/4" x 2-1/2" ellispe)
RANDOM Volume of core catalyst block is 120 cubic inches
RANDOM neck flow area is 25.525 square inches
(For reference, the flow area of a straight 3" pipe is 28.27 square inches)
Cat. and Y-pipe Cat. Adaptor prepared for install
Drivers side header installed with AIR hooked up, wires
Passenger side header installed with AIR hooked up, wires
Drivers side Made-For-You wire looms - Centerbolt VC type
(Thanks to Greg Westphal for the wire loom tip...)
Cat. Adaptor hooked to Y-pipe and Cat.
