Paul,  ever since I "finished" the prototype p port intake manifold,
I had intended to make it one more time,  cleaner and  lower across
the top of the engine.  The original intake was completely steel
except for the bell mouths.  The new version will have steel runners
but the bells, and plenum will be aluminum. On the first version, I
needed to tighten the radius of the 1.75 o.d. steel tubes U-bend
slightly and I did so by band sawing out a tiny pie section  (about .
125 wide) which when pulled closed and welded gave me the fit I was
looking for.  This time I got to wondering if I could just tighten
the bend radius by force to to get the desired effect. So starting
with a steel u-bend clamped in the vise, I inserted a  three foot
long piece of pipe  as close to the tubing  i.d. as I could find
lying about.  I gave a gentle pull and the bend closed a few degrees
easily WITHOUT DISTORTION, at least none that I could see.

For those who are using steel intake tubes, have at it without
fear.  Just move slowly and in small increments. I tried the same
with a piece of 2" aluminum (.065 wall) and got the same results,
sort of.   I did not bend the aluminum very far ( just a degree or
two) because it started to move in the vice and I did not want to
apply more clamping pressure.

 This may be useful for those who are fabricating aluminum intakes
as they will be able to alter the 3 inch bend radius at least a small
amount.  I have not tested  to find the limits. If much pressure is
applied clamping aluminum tubing in the vice is sure to distort
it.    A bending form built out of plywood with blocking to control
the amount and location  of the  bend should be built. A bending
lever that fits tightly inside the aluminum tube with a split clamp
around the outside would protect the end of the  tubing.   Also, this
is for 6061 T-6 bends.  The soft bends sold by R & B Wagner would not
stand up to this kind of treatment.

 Jerry



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