Need help with big block swap in 67c10

[67ctener]

Have a few questions about my big block swap. I bought a 71 factory big block truck and during the swap noticed a few things. First is on the 67 the holes for the frame towers are center of frame, the 71 bb truck are offset maybe 3/16. Second is the frame is notched quite a bit on the passenger side. Do I need to notch my frame? I wish I paid attention more when it was assembled but its to late. I'm assuming its notched to clear ps pump and pulley.
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[67c10rustbuket]

Hey stranger, actually the holes are in the exact same spot, the issue is in 68 and later when big blocks were available they narrowed the top flange of the frame for exhaust clearance. It is pretty common on 67s to have to thin the top frame rail behind the motor mount stands.
My 67 frame upper flanges were 2.5" and my friends 72 measured 1.8" so I trimmed mine down by just over .5". I am not using a big block but just wanted clearance for sbc headers as my previous set were rubbing the frame. Here is a pic, I actually just did this last week. Have not cut your pillars out yet because I was doing this

[67ctener]

This is what I wasn't wanting to do. How did you cut your frame? It's powder coated so I don't wanna put heat to it. Is this necessary to cut the frame if I run specific big block headers for this truck?
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[67ctener]

And no rush on the patch panels, whenever you get to it
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[67c10rustbuket]

I really don't know if there is a BBC header that will fit without trimming, maybe someone else can shed some light on that. I saw others use Chevelle BBC headers but I cant say anything for fit since I never got that far. I initially had a 68 short step and a 454 then got my 67 and later decided I wanted to be able to pay for gas so I went back to an SBC.


Answer from the other post pic'd. Hard to read so I pasted the text here.

Quote from other thread:

Quote:
Originally Posted by 67ctener

How'd you trim your frame rails?
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I use the Dewalt .045 cut off wheels on my 4.5" grinder. I taped off the cut line and first walked the cut off wheel down the cut line to kinda score the line thinking it would help keep it in line when I cut through. I cut through very carefully and keep a steady hand. In your case being powdercoated it would probably get hot and mess up the finish, I have cut powdercoated steel at work and it does burn a little at the cut. If you cut yours maybe tape the whole frame rail and cut through the tape? I hear this reduces chipping. I was not to concerned because I had to finish painting a few places anyway.
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[67ctener]

Man I thought all I needed was these frame mounts. I almost wish I just stuck with a sb but I bought a truck just for the big block. I almost thought to try a jigsaw. I went a few steps backwards today
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[67c10rustbuket]

I personally would try fitting some headers before cutting since yours is powder coated. I read elsewhere that someone only needed to trim the frame for the bbc motor mount stands in a 67 frame and that headers fit fine.

Any one else done this ?

[midniteblues]

havent done it yet but I'm not too far away from doin it.
I have a set of 68-71 bbc mounts and a complete fresh paint on the frame.
I knew before hand i would have too cut for the mounts but i wanna hold out cutting the entire length too see how everything is gonna fit.I'm gonna try a set of 69 camaro hedmans(what i have allready)if they dont work then I'm not sure,either get new headers(most expensive way) or just reuse some manifolds(cheep ass way) i dont want it hanging below the frame but my big challenge is wanting too clear the z bar