Victor Laury wrote:
>
> The interior is rough and the bores are at least a 32th
> smaller than the phenolitic blocks.
>
> Does anybody know if there is an advantage to spending some time smoothing
> the passages and porting them to match the blocks?
>
Yep, your biggest gain would be in matching the ports (called "port
matching" oddly enuf) between carburetor, manifold, and head. Smoothing
wouldn't hurt, but it won't make massive gains, either.
There's a process called 'extrude hone' where water with abrasive is
shot thru your manifold, doing a VERY good job of flowing it. However,
with SU's, I wonder if the work is worth the money. The manifolds are a
straight shot, and the carbs aren't exactly hi-tech by any (post WW2)
standard.
Also, don't polish the insides of the manifold TOO much, as some
turbulence has been proven (by racers, not me!) to help even out the
mixture in the cylinder. THis would seem to be especially true of the
SU, which dumps its fuel into the bottom of the manifold rather than
making an attempt to get it into the center (a la almost any other carb)
But heck, grinding aluminum is fun,
just don't add a fresh air port!
Toby B
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