455 cross over patch... i want dual exhaust

greener_dude · 02-18-2007, 08:19 PM

just wondered what people have used to patch the cross-over hole so that you can run duals off the manifold. Im looking to make cheap power and something that sounds cool. Im thinking a plate of stainless steel and then something to seal it up. hi-temp gasket maker? ... not sure what to use

2blu442 · 02-18-2007, 08:38 PM

Two things I've seen done is to keep a few inches of the exhaust pipe from the crossover and weld a cap on the end of it. Simpler, but not as pretty is leave about 6 inches on it, pinch it, and run a bead of weld to seal it. Either of these will keep the correct seal against the manifold.

mitsudave · 02-19-2007, 06:01 PM

My exhaust guy did the former...he cut a three or four inch piece off the crossover pipe and welded a cap on the end...it works like a charm!

greener_dude · 02-21-2007, 02:45 PM

These are fab's that i've thought about its just i want a smooth look and dont care much for the antler type method. you can't really weld cast can you? Id like to make a patch and then weld it in kinda like you you would go about shaving door handles or a key hole. any thoughts? I have a mig and a stick welder - not sure what rod or wire i need.

Oldsguy · 02-21-2007, 05:16 PM

I don't weld but had that done. I cut the manifold like you described and took it to a welding shop I trust, they welded on a metal plate and from the top you can't even tell. I would think it would flow more like a stock dual exhaust manifold (W/Z type) too. Additionally, I found a different driver's side manifold from a Toronado, it dumped down on the steering box ('69 Delta) since the car is rear steer so I cut the manifold at the collector end and rotated it 180 degrees and had the shop weld that too so the down tube could bolt up to it and then drop down in front of the firewall. Poor man's W/Z manifolds and definitely cheaper than custom headers and quieter too.

Eightupman · 02-22-2007, 06:27 AM

Quote:

Originally Posted by greener_dude

These are fab's that i've thought about its just i want a smooth look and dont care much for the antler type method. you can't really weld cast can you? Id like to make a patch and then weld it in kinda like you you would go about shaving door handles or a key hole. any thoughts? I have a mig and a stick welder - not sure what rod or wire i need.

Use the stick welder and use a high nickle rod. That will weld cast iron nicely. There is a guy in town who will weld blocks with it and it holds like a champ.

John

greener_dude · 02-22-2007, 06:33 PM

thanks for the tips guys. I feel that the stock manifolds flow good enough that its worth the time doing this mod vs. having to buy headers or the w/z manifold. After this step im only a few more weekends away from doing a startup on the engine stand just to varify a few things before it goes in the car. Might as well find the problems while the eninge is out rather then hunched over the fenders.

02-18-2007, 08:19 PM	#1 (permalink)
greener_dude Junior Member Join Date: Feb 2007 Posts: 8	455 cross over patch... i want dual exhaust just wondered what people have used to patch the cross-over hole so that you can run duals off the manifold. Im looking to make cheap power and something that sounds cool. Im thinking a plate of stainless steel and then something to seal it up. hi-temp gasket maker? ... not sure what to use

02-18-2007, 08:38 PM	#2 (permalink)
2blu442 Senior Member Join Date: Sep 2006 Location: Medford, Oregon Posts: 808	Two things I've seen done is to keep a few inches of the exhaust pipe from the crossover and weld a cap on the end of it. Simpler, but not as pretty is leave about 6 inches on it, pinch it, and run a bead of weld to seal it. Either of these will keep the correct seal against the manifold. __________________ 1964 Cutlass Factory 4spd 1965 442 4spd 1967 442 Auto 1967 Cutlass Convertible 1968 442 Auto 1969 442 W30 Auto 1970 442 4spd 1971 Cutlass Flat Top Wagon 1973 Che*vy 3/4 Ton 454/TH400 Tow Vehicle Only the tow vehicle is finished!

02-19-2007, 06:01 PM	#3 (permalink)
mitsudave Member Join Date: Jan 2007 Location: Palm Bay, FL Posts: 54	My exhaust guy did the former...he cut a three or four inch piece off the crossover pipe and welded a cap on the end...it works like a charm! __________________ Dave Paulison Palm Bay, Florida 1969 Olds Cutlass Supreme

02-21-2007, 02:45 PM	#4 (permalink)
greener_dude Junior Member Join Date: Feb 2007 Posts: 8	weld-in patch on cast manifold? These are fab's that i've thought about its just i want a smooth look and dont care much for the antler type method. you can't really weld cast can you? Id like to make a patch and then weld it in kinda like you you would go about shaving door handles or a key hole. any thoughts? I have a mig and a stick welder - not sure what rod or wire i need.

02-21-2007, 05:16 PM	#5 (permalink)
Oldsguy Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 2,859	I don't weld but had that done. I cut the manifold like you described and took it to a welding shop I trust, they welded on a metal plate and from the top you can't even tell. I would think it would flow more like a stock dual exhaust manifold (W/Z type) too. Additionally, I found a different driver's side manifold from a Toronado, it dumped down on the steering box ('69 Delta) since the car is rear steer so I cut the manifold at the collector end and rotated it 180 degrees and had the shop weld that too so the down tube could bolt up to it and then drop down in front of the firewall. Poor man's W/Z manifolds and definitely cheaper than custom headers and quieter too. __________________ Dan '46 2 door

02-22-2007, 06:33 PM	#7 (permalink)
greener_dude Junior Member Join Date: Feb 2007 Posts: 8	thanks for the tips guys. I feel that the stock manifolds flow good enough that its worth the time doing this mod vs. having to buy headers or the w/z manifold. After this step im only a few more weekends away from doing a startup on the engine stand just to varify a few things before it goes in the car. Might as well find the problems while the eninge is out rather then hunched over the fenders.

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