Rb20/rb25 Head, Bnr32 Manifolds (exhaust)

[GTScotT]

Hey,

I have searched yet did not find an answer to my question,

i wondering if its possible to drill about 10mm deep into a rb20 or rb25 head were the studs are for the 4 holes that dont line up on the rb26dett exhaust manifolds or if i will end up drilling into a water or oil galary

thanks

Scott

[R31Nismoid]

You need to get adaptor plates made up to use the manifolds.

This has been covered a few times now.

[GTScotT]

You need to get adaptor plates made up to use the manifolds.

This has been covered a few times now.

i read that you needed adapter plates, yet hadnt found if anyone had tried to drill and tap the head instead.

thanks

[Nismo_Boy]

yet hadnt found if anyone had tried to drill and tap the head instead.

Because it’s a stupid idea as tapping the head is more effort?

I have used GTR manifolds on an rb25 head. It was/is/will be more easier to change the flange's on the manifold. I even used the GTR flange's that were cut off, adjusted them to suit the rb25 stud pattern and re welded.

[GTScotT]

Because it's a stupid idea as tapping the head is more effort?

I have used GTR manifolds on an rb25 head. It was/is/will be more easier to change the flange's on the manifold. I even used the GTR flange's that were cut off, adjusted them to suit the rb25 stud pattern and re welded.

so cutting a CAST IRON manifold, well 2, and then needing to stick weld with cast nickle rods and hope it doesnt crack when cooling, is going to be more easy than putting a big chunk of alloy into a drill press and drilling 4 holes after u mark and center punch them, then running a tap threw them?

anyway im not asking whats easyer to do, im asking if anyone knows if there is anything in the meat of the head there before a depth of 10 mm so i know if its safe to drill.

[STATUS]

so cutting a CAST IRON manifold, well 2, and then needing to stick weld with cast nickle rods and hope it doesnt crack when cooling, is going to be more easy than putting a big chunk of alloy into a drill press and drilling 4 holes after u mark and center punch them, then running a tap threw them?

anyway im not asking whats easyer to do, im asking if anyone knows if there is anything in the meat of the head there before a depth of 10 mm so i know if its safe to drill.

the adapter plates ive used in the past bolt on and are super easy to make and use....not welding reuired and last forever.

Tapping the head is NOT a good solution.

[STR8E180]

adapter plates is the best way around it

i wouldnt recommend cutting and welding cast iron

sure it can be done but its not going to be very strong