Bolt-on horsepower and torque with Scott Drake Tri-Y headers. These headers are designed to fit 64-68 Mustangs with 260, 289 and 302 engines with automatic and manual transmissions. Although they look like average Tri-Y headers, these Scott Drake designed headers have been refined to provide ample clearance around the starter, steering and shock towers* for a superior fit. They are engineered to make strong power and torque throughout the RPM range with mandrel-bent 1-1/2" primaries, 1-3/4" secondaries and 2-1/2" collectors. Exhaust port size is 1-1/2" x 1-1/4". Each header is manufactured with heavy-duty features like extra-thick 5/16" laser cut flanges that have been machined flat to guard against warping and heavy-wall 16 ga tubing for superior durability. These headers are then finished in an extreme hi-temp silver ceramic coating for the ultimate thermal protection. This header system includes high quality hardware, premium laminated metal core gaskets, and 2-1/2" - 2" starter tubes with collector flanges for a professional installation. Note: *1966+ motor mounts are recommended for proper shock tower clearance. Designed to work with common 157 tooth bell housings. Larger 164 tooth bell housings will require modification for proper clearance. Cars with power steering will require p/n DBPP-10961-A power steering ram drop down bracket.