Exhaust manifolds



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Oct 26, 2014
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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
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
I read from someone named Kimmer that it would. I’m not gonna spend the money that’s wanted for oem’s. Thanks, Mark
I shorted the steering shaft tube. Can’t remember with how much, but it did work. Mine is a 4-speed I should ad, considering the disagree note
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I have a console shift. I was wondering if it would be necessary. Thanks!
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
Thanks Kim. What did u do for bolts/studs? I assume that the head and manifold holes don’t line up when ur done milling?
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
I read from someone named Kimmer that it would. I’m not gonna spend the money that’s wanted for oem’s. Thanks, Mark
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.
Trim the column, cut an access hole for #6 plug and it will fit fine, no milling and even with power steering and a 440!




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68 B body HP manifold on 440 68 Dart - Hits the firewall so studs don't line up:

Manifolds1 (480x640).jpg

Manifolds2 (480x640).jpg
I think c body hp manifolds come forward at the back. That would eliminate that problem.
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.

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.
Accurate was way too expensive. Probably why they don’t make them anymore
Use bolts for install? Or will it clear studs in a 67/400/451? Anyone know? Thanks
You shouldn't hit the fire wall on the drivers side. What motor mounts are you using? I used the Schumacher mounts and you could turn them 90 or 180 degrees.