I learned through experience how to install the Rockwell manifold. It is a
great replacement for that cast iron boat anchor that Olds used. There is
one shortcoming. The lower casting on the intake ports is a bit shorter
than the stock iron manifold, and requires very precise placement and
alignment when you install them. Easy to do when the engine is on a stand,
but a bitch when hanging over the hatch. I invert the manifold over a block
on the bench, and spray adhesive onto the intake ports. Then, spray the
gasket with 2 wet coats and apply it to the manifold and align the gasket
with bolts. Leave it overnight. Use "the right stuff" sealant around the
water passages on the 4 corners of the manifold, a big dab on each corner
where the heads meet the block and manifold, and a 3/16" ribbon on the end
walls. Let that tack up a bit, so that it does not stick to your finger.
Then, place the manifold carefully, align the holes with taper punches, and
use new bolts and thick washers. Tighten the manifold using Olds
recommended sequence. If the gaskets slip, your engine will drink oil from
the valley. This is only a problem for the 455. The 403 uses a turkey tray
intake gasket. If you want more details, call me.
Jim Hupy
Salem, Or
> I was wondering about that...
>
> When we installed Gary's manifold on my new engine, both me and John Beaver
> were quite pleased at how light it was. There was no evidence of any
> problem after thousands of miles on the old engine.
>
> My only strong recommendation with that manifold is to install studs for
> the thermostat housing. Unlike on the iron manifold, the threaded holes
> don't penetrate the water jacket and they aren't deep enough for any
> standard-length bolt that won't bottom out.
>
> Also, they need high-collar washers on the intake bolts, instead of
> standard flat washers, which won't seat on the machined washer surface. I
> corrected that issue with the motor, also.
>
> I used the thin gaskets and block-off plates that Dick provides.
>
> Rick "hoping Gary survived that ordeal" Denney
>
>
> > Arg! How did I type that? I knew it was actually Gary Rockwell. haha
> I
> > don't know how the developer of an alternative airbag system got in
> there.
> >
> > duh
> > bdub
> >
> >
> > > Mark Wall used an amazing process to create that manifold. Charles
> > Wersal
> > > sent him a manifold he didn't need any longer to sacrifice for the
> > greater
> > > good. Thankfully he documented it faithfully.
> > >
> > >
http://www.gmcmhphotos.com/photos/g3738-gmc-intake-
>
manifold-project.html
> > >
> > > bdub
> >
> > --
> Rick Denney
> 73 x-Glacier 230 "Jaws"
> Off-list email to rick at rickdenney dot com
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