47-55.1 Anyone have to notch their frame for exhaust.

[Mains52]

I went to slide my ls3 exhaust manifolds on after I had already positioned the motor mounts and trans x member. Well they dont fit in between the frame. Anyone else had this problem? I think I seen somebody notch the frame in the projects but maybe I am wrong really didnt want to move the motor but it is what it is. Thanks

[joedoh]

Originally Posted by Mains52

I went to slide my ls3 exhaust manifolds on after I had already positioned the motor mounts and trans x member. Well they dont fit in between the frame. Anyone else had this problem? I think I seen somebody notch the frame in the projects but maybe I am wrong really didnt want to move the motor but it is what it is. Thanks

the guy I helped with a 53 original frame MII 5.3 had to notch his frame. you can see in the picture his manifold is loose and if you tighten them the collector would hit the frame.

it was a real pain getting the shaft routed around them too, hope you dont have that problem.

[edgeleycanuck]

There are cast manifolds made by hooker and others that may have the collector tucked in a bit more? Just a suggestion.

[mr48chev]

I'd first sort though listings for oem LS manifolds for that side or both sides.

Check on some of the LS swap groups and pages to snoop out factory manifolds that tuck in closer.

On the right side on my 71 GMC with the 500 Cad my son and I heated and then reshaped the area on the frame where the right manifold hit the frame. You don't really notice it unless you are looking for it and it didn't take any strength away like cutting the frame would.

[joedoh]

those are car manifolds in my picture, mr48, and you may not be up on the models but the LS3 is a car engine too.

the car manifolds are a lot smaller and closer like you say, the truck manifolds on the 5.3 would have needed step notches haha.

[Mains52]

Originally Posted by joedoh

those are car manifolds in my picture, mr48, and you may not be up on the models but the LS3 is a car engine too.

the car manifolds are a lot smaller and closer like you say, the truck manifolds on the 5.3 would have needed step notches haha.

These are ls3 manifolds on a 5.3. My only worry with notching the top half would be strength that close to the front end. From what I can tell they are almost the same design as the hooker ones. I already have the trans x member welded into place so I really dont want to raise it but I guess I have to consider all the options.

[joedoh]

Originally Posted by Mains52

These are ls3 manifolds on a 5.3.

thats whats in my picture too.

i was telling mr48 his advice to visit the ls forums and ask about manifolds would yield the same result, the camaro manifolds are the the ones everyone uses for tight areas.

raising the motor is a possibility, I see guys selling mounts for 5.3 that keep the truck oil pan and manifolds, although at the expense of a lot of floor real estate in trans and driveshaft tunneling.

[SFFD103]

I had my guy notch my frame rail for 2016 Camaro SS manifolds.

[jocww]

Sanderson makes a set. You can look at my build for pics

[daveshilling]

Trailblazer SS manifolds hug tight. I have them on my LS and there is tons of space. GM part, cheaper than aftermarket too.