Hi all. Happy Thanksgiving! Question; ive read that angle milling big block hi po exhaust manifolds will make them fit a Big blockA body swap? If so, does anyone know for sure how much to mill off and which bolts/ studs to mount them? After milling I figured the holes would be out of alignment. I’m using edelbrock rpm heads and a B engine. Which obviously has the lower deck height. Thanks in advance for any help! Mark
Exhaust manifolds
- Thread starter cuda620
- Start date
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4mulas
Fixem'up
I don’t think this is possible. The outlets leg on the left side is completely different, don’t think any amount of milling will make it workable…
a body
the top manifold is drivers side in both pictures
b body
a body
the top manifold is drivers side in both pictures
b body
Mark, I have milled the C body drivers side 1/16 on the angle. If u go anymore the flange will hit the block. The B body will fit without milling but u have to shorten the steering column housing to the firewall. U could have the b body milled if u wanted. Kim
Yes they are off a bit. I had a thick flat washer milled on the angle. Then I super glued them to the manifold. This trick only works once. I have friends that just used the factory stuff or header bolts and they seemed to work fine. Kim
The 68 and 69 B body manifolds will fit good with the low deck in a 67 and up A body. You'll need to cut the steering column housing about even with the firewall and do away with the column shifter mechanism and convert to floor shift. The C body HP manifold also will fit. That's the one that sometimes requires milling so that the outlet is closer to the engine. The passenger side B body HP manifold pretty much just falls in. With the RB engine like a 440, People have also made those fit, but it starts getting pretty dang tight.
Yup, makes a big difference.
1968rt
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From what I recall a C Body drivers side will cost you at least 5-7 HP. An original A body BB Drivers side will cost you about 12HP. There was an aftermarket drivers manifold that looked like an original A body without the restriction. Made by Accurate.
pishta
I know I'm right....
I angled milled a Hi-po drivers side manifold just a few degrees and it fit a 400 in a NARROW 65! The only reason you need to do this is to get the steering shaft to clear the manifold. In a 67 or newer I don't think this is even needed. This was after I shimmed the mounts as far over to the passenger side as I could and even slotted the steering box bolt holes about 2mm. I studded 5th manifold bolt and bent it down a little so the nut would go on flush. I would machine the steering shaft down about 2mm if I had to do it again and run solid motor mounts again. The Accurate manifold did not have the steering clearance, makes you wonder why the original had to have it.
I had the factory studs on my 383 builds. Kim
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