Doug Thorley tri-y's
I've got them on my '82 F150, 2WD, 351W and I love them!! They fit really nice, sound good, look good, have a nice thick flange that doesn't warp, and awesome gasket that doesn't leak. I can't tell whether they increased torque since I put them on when I swapped in the 351W replacing my 300 I6.
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Slik
'82 F150 351W
(Was a 300 I6)
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Slik
'82 F150 351W
(Was a 300 I6)
The Tri-Y pattern is designed to scavenge at low revs and promote low to mid-range torque. At high revs they give a little more back pressure than 4-into-1 designs so they sacrifice of some top end HP. They are probably the best header for most truck applicarions.


