CA Thorley 399Y-3 Headers, Magnaflow muffler - The 1947 - Present Chevrolet & GMC Truck Message Board Network

JEM · 05-03-2011, 05:14 PM

More stuff off the '91 Suburban.

This time a set of Thorley 399Y headers (I think it's the 399Y-3 the difference between the 1, 2, 3 is just the tailpipe to the muffler), cataloged for '86-91 big-block 2WD 3/4 and 1-ton Subs, crew cabs, etc. and '86-87 trucks (the Y-pipe is set up for a single 3in exhaust, and that's how I ran it, but I suppose you could run dual exhausts down the left side...) About ten years old. Minor rust pitting, the headers and the Y-pipe were blasted and ceramic-coated about three years ago; some surface rust is creeping back through the coating especially on the Y-pipe as seen in the pics but the metal is sound. They're a nice piece of gear.

The Y-pipe has had a second O2-sensor bung added (for a wideband tuning sensor.) The second primary on the right side has a -10AN weld bung near the head flange, this was used for an external EGR tube to the intake to make my EGR functional since my Vortec heads have no exhaust-heat passages. I'll provide a steel AN cap for the AN bung and a plug for the second O2 fitting.

$150 obo + shipping.

Or you can pick them up, or if you're within 60 or so miles of San Mateo CA and we can figure out the schedule I'll deliver.

Please note that the headers and Y-pipe weigh approximately 45lb packaged, and are bulky (40x36x12 approx). Approximate shipping to (just as an example) Columbus, OH - $60 Greyhound (you pick up at bus terminal), $100 USPS Parcel Post, $155 Fedex Home Delivery (UPS similar.)

Also available as seen in the picture:

The inlet pipe from the Y-pipe to the muffler (still attached to the muffler in the picture): if you're buying the headers and want this I'll cut it off and include it with the headers.

The Magnaflow muffler - don't recall what model, 3in center inlet/center outlet, about seven years old and in very good condition, $25 + shipping, about 20lb.

Other items still for sale:

A complete power mirror setup: http://67-72chevytrucks.com/vboard/s...d.php?t=462441

Smittybilt CN15-S4B steps: http://67-72chevytrucks.com/vboard/s...d.php?t=461723

JEM · 05-16-2011, 02:48 PM

bump

JEM · 05-27-2011, 11:14 AM

bump

JEM · 06-10-2011, 11:39 PM

bumpity-bump.

Oh, and after further research looks like the part # for this set is 399Y-1S. Only difference is still the Y-pipe-to-muffler connector.

05-03-2011, 05:14 PM	#1
JEM Ironmonger Join Date: Dec 2004 Location: SF Bay Area, CA Posts: 127	Thorley 399Y-3 Headers, Magnaflow muffler More stuff off the '91 Suburban. This time a set of Thorley 399Y headers (I think it's the 399Y-3 the difference between the 1, 2, 3 is just the tailpipe to the muffler), cataloged for '86-91 big-block 2WD 3/4 and 1-ton Subs, crew cabs, etc. and '86-87 trucks (the Y-pipe is set up for a single 3in exhaust, and that's how I ran it, but I suppose you could run dual exhausts down the left side...) About ten years old. Minor rust pitting, the headers and the Y-pipe were blasted and ceramic-coated about three years ago; some surface rust is creeping back through the coating especially on the Y-pipe as seen in the pics but the metal is sound. They're a nice piece of gear. The Y-pipe has had a second O2-sensor bung added (for a wideband tuning sensor.) The second primary on the right side has a -10AN weld bung near the head flange, this was used for an external EGR tube to the intake to make my EGR functional since my Vortec heads have no exhaust-heat passages. I'll provide a steel AN cap for the AN bung and a plug for the second O2 fitting. $150 obo + shipping. Or you can pick them up, or if you're within 60 or so miles of San Mateo CA and we can figure out the schedule I'll deliver. Please note that the headers and Y-pipe weigh approximately 45lb packaged, and are bulky (40x36x12 approx). Approximate shipping to (just as an example) Columbus, OH - $60 Greyhound (you pick up at bus terminal), $100 USPS Parcel Post, $155 Fedex Home Delivery (UPS similar.) Also available as seen in the picture: The inlet pipe from the Y-pipe to the muffler (still attached to the muffler in the picture): if you're buying the headers and want this I'll cut it off and include it with the headers. The Magnaflow muffler - don't recall what model, 3in center inlet/center outlet, about seven years old and in very good condition, $25 + shipping, about 20lb. Other items still for sale: A complete power mirror setup: http://67-72chevytrucks.com/vboard/s...d.php?t=462441 Smittybilt CN15-S4B steps: http://67-72chevytrucks.com/vboard/s...d.php?t=461723 Last edited by JEM; 05-03-2011 at 06:07 PM.

05-16-2011, 02:48 PM	#2
JEM Ironmonger Join Date: Dec 2004 Location: SF Bay Area, CA Posts: 127	Re: Thorley 399Y-3 Headers, Magnaflow muffler bump

05-27-2011, 11:14 AM	#3
JEM Ironmonger Join Date: Dec 2004 Location: SF Bay Area, CA Posts: 127	Re: Thorley 399Y-3 Headers, Magnaflow muffler bump

06-10-2011, 11:39 PM	#4
JEM Ironmonger Join Date: Dec 2004 Location: SF Bay Area, CA Posts: 127	Re: Thorley 399Y-3 Headers, Magnaflow muffler bumpity-bump. Oh, and after further research looks like the part # for this set is 399Y-1S. Only difference is still the Y-pipe-to-muffler connector. Last edited by JEM; 06-11-2011 at 12:35 AM.



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