exhaust question

[michael bustamante]

doing a 5.3 ls swap with 4l60 tranny from a 03 yukon
do i need the y pipe with the cats to drop in my 67 chevy? i have the truck on CL for parts and alot of people ask me for the y pipe.

[BR3W CITY]

only if you plan on running the stock cat for some reason. Usually only the CA guys need to run the emissions stuff.

[LeesTruk]

Depends on what you're gonna do for an exhaust system. If you choose headers, then no , the Y isn't needed. If you're gonna use factory cast manifolds, you'll want to use a portion of each leg of the Y (cut below the O2 sensors) to graft your new pipes onto. Here in CT, we can sell the used cats to a recycler, don't know about your state. I'm guessing maybe that's why people are asking for your Y pipe, so don't just "give" it away

[72MARIO]

Used cats up here in Ontario are worth over $50

[michael bustamante]

i was actually thinking i had to use either tbss, cts-v or headers. so the stock y pipe will not work for any of these applications will they?
How come the manifolds on the engine now wont work? do they exit right at the frame?
Im new to the ls scene and actually havent even done it yet, im one of the oldie but nubies collecting all the info i can before i stuff this motor in the 67

[72MARIO]

I am in the same position as you. I cant get a solid answer either. The truck manifolds exit into the frame rails a little tricky routing the pipes out and down. The passenger side does not work without cutting or heating the top of the frame and bending it out of the way. The best fitting manifolds i have seen are 2010 camaro manifolds.

[BR3W CITY]

Originally Posted by 72MARIO;7435037I

cant get a solid answer either.

There is no solid answer, welcome to hot rodding

Truck manifolds don't work usually because; the bump on them hits the frame, the mounts being used don't clear them, they exit in an unfavorable angle for really lowered trucks, and they really aren't that great in terms of flow. No reason to "make" them fit just to end up with a sub-par manifold.

[LeesTruk]

Using the Camaro manifolds creates a situation where you need to find the correct flange (two studs) to weld your exhaust pipes onto. The use of Trailblazer/Rainier 5.3L manifolds are advantageous in that they are narrower than the truck manifolds, but have the same flanges as your Y pipe. By narrower, I mean they hug the block tighter, so that reworking the frame is not necessary. Being narrower, though, means you can't use your Y pipe as it exists, unless you modify it to fit, or you create a new Y pipe, such as this;



Unless you're power crazy like some of the young studs here (not a slam, guys), you'll find the LS power more than ample in stock/semi-stock condition, and if it's just a simple street/work machine, you'll never realize the brute power these engines can produce, because you won't need to. In most cases, the KISS method is best

[Houston Ben]

The truck exhaust manifolds will work, you do have to bend the frame a little and you have a sharp angle on the drivers side, but they will work, I have them on right now.

Having said that, I wish I would have just buck up for the camaro ones or similar for a cleaner look.

[michael bustamante]

ok so if i cut the flanges right after the o2 sensor housings and use the tbss or camaro manifolds i should be ok? I told some kid we could do the cats for 40 each.

[LeesTruk]

There's a difference between the two manifold flanges. Camaro's have two studs, the truck/ suv's have three studs. Your Y pipe has the three hole flanges. If you decide to go Camaro, then you have to build from the manifold back using a flange you have to locate/buy, then prep the exhaust pipes for a bung and O2 sensor. With the SUV manifolds, you can cut below the existing Y pipe O2 sensors giving yourself plenty of pipe to graft onto, then sell your cats to support the rest of the exhaust system cost. My Y pipe was about $80 to build (mandrel bent pipe and a Y collector). My entire exhaust system cost was about $230, but I made it myself so to keep the cost down. It's a single pipe system, 2 1/2" pipe to the Y and 3" from the Y to the muffler (Walker Quietflow SS) and 3" tailpipe over the axle to the right rear of the truck

[BR3W CITY]

FWIW The 3 bolt flanges come pretty close to the ears on the 4l80e. Mine were trimmed for clearance anyway, just be aware that it might occur.

[michael bustamante]

dang man, i was hoping the flanges would be the same. do the tbss manifolds use the same flange as what i have now?

[LeesTruk]

Yes. Also know that the TBSS manifolds are the SAME thing as the Trailblazer and Buick Rainier 5.3L manifolds, so don't limit your search to just the TBSS pieces. Dorman Products sells a new Trailblazer 5.3L manifold for the pass. side, but not the drivers side (don't know why that is). I found my drivers side manifold (Buick Rainier) on ebay, from a boneyard in Washington State for $60 (buy it now) and had it within 4 work days

[michael bustamante]

ok great thank you for the info!! so cut the y pipe i have now just under the o2 sensors and sell the cats, find rainier or tbss manifolds and im one step closer! thank you

[michael bustamante]

anybody selling their tbss envoy or rainier manifolds?

[Root2812]

Either way save those flanges on the y pipe. I made the mistake of buying manifolds without them and I have found it hard to find the flange separately so I can make a exhaust. Fortunately I am using the 2002 Corvette manifolds that have the O2 sensor bung built into them and not the y pipe so I only need to find a flange and weld a pipe to it. So if you don't end up using them save them incase you do another build and don't have them.

[BR3W CITY]

If you don't have the flanges and are trying to build the exhaust, allow me to blow your mind for a minute. The only reason to use the factory flange style is if you already have the parts.

If your welding the system yourself, the cost of switching to a vband isn't insanely different from the cost of laser cut flanges. Most of the ypipes/downpipes/bpipes/collector pipes/flanges you'll find second hand (especially in the midwest) are already warped or rusted, the pipes attached to them are swiss cheesed and have rusted/crossed thread or broken sensor bodies in them. If you factor in the cost of not having to ever use a gasket, and not having the flange related clearance issues....they offer some distinct advantages.

If I ever needed to redo a stock manifold setup again, I'd do it that way just to not have to worry about exhaust gasket issues.

[solidaxel]

I have found these manifolds to be Cast Steel not cast iron, so you can cut and weld flanges or V-bands on them
I just purchased a dozen 2 1/2" V band clamps from Ace Race good price and good quality, I have two systems To build

[michael bustamante]

what are v bands? you got a pic of them?

[BR3W CITY]

[michael bustamante]

br3w, you got a pic of one of these installed? i got a lead on camaro manifolds but no y pipe, so i think im gonna go this route....

[BR3W CITY]

These arent my pics

[michael bustamante]

cool man thank you. im going to have to look into those

[Root2812]

So can you use these on cast manifolds? I have these 3 bolt flange ones with the donut gasket. Like the ones at this link... Can I use v-bands or am I up a creek?

http://img.photobucket.com/albums/v3...05747Small.jpg