wrenchtech

I don't know if they are cast iron or cast steel, or how they respond to welding. I was thinking of taking a couple inches off of a passenger side manifold so I could flip it over to the driver side. Then I could delete the crossover pipe and merge the exhaust underneath the truck instead.

wyoming9

iTrader: (1)

At this point just buy a set of headers .

It is the thermal cycling does the weld in finding a filler metal that expands and contracts the same as the casting is the problem

You can try using the Ni99 electrodes then you also need to preheat and control the post welding cool down .

then it needs to be welded on a jig with the manifold torqued to specs .

This is just for trying to fix a small crack .

Your wanting to do major fabrication .

Buy headers much less frustration and wasted time .

Then after all it is your vehicle so you might want the learning experiences.

Get it all done bolted in place have your new exhaust system made only to have it crack the first time it gets hot and cools down

wrenchtech

You might be right if just for the reason that the factory crossover pipe diameter is 1-1/2" and so is the output of the factory manifold. I might be able to open it up a bit , but 1-3/4" would probably be the maximum. That seems kind of small. I notice that the Doug Thorley headers have 1-1/2" primaries and a 2-1/2" collector. I'm not dumping $600 into a header for a 3VZE though.

wrenchtech

After doing some more reading on the subject I would say welding a cast iron exhaust manifold is one of the most difficult welding jobs there is and not likely to produce a good outcome. Next I might look at making something up with a header flange from L C Engineering and some weldable .pipe elbows.



$49 each http://www.lceperformance.com/Header...-p/9010047.htm


$6 ea
http://wrenchte.ch/2sulqsr

wrenchtech

The driver's side manifold is so close to the firewall that you would want to design any kind of alternative manifold to dump downward between the number 4 and #6 cylinders like the stock manifold.