73 Chevy v8 question

[Shannen Durphey]

Stowe, Ted-SEA wrote:
> 
> Thanks very much to everyone for helping me id my Chevy 350.
> 
> I believe it to be a '73 350 out of a passenger car, which one I can't tell,
> I am assuming a 2 bolt main. whether it was rebuilt or not I can't tell.
> 
> the head casting # is 3973487
> the carb id, (2bl Rochester ) is 7043114
> the block id is 3970010
> the intake is 3997773
> 
> the distributor I can't find listed anywhere, it is a 1111440  8c19, the
> 8c19 would normally tell me that the distributor was built on march 19th
> 1978, but how that got there I can't tell. It is a single point dist.
> 
If you have room, consider an HEI swap.  So good, you'll never want to
leave home without it.

> I cannot get the waterpump nor the exhaust manifold numbers.
> 
> a great numbers book is 'Chevrolet by the numbers' really nice for this sort
> of thing.

Do you have this book?  Can you look up the cylinder head number I
posted a couple of days ago?

> 
> I have a question about the intake manifold, this is not a efi question, I
> wish it was but I am trying to do the right thing here. Putting an efi
> system on my mgb has taught me to pay lots attention to details and think
> before doing anything.
> 
Good for you.  You learned after the first try. ; )

> I took the carb off and sent it out to be rebuilt, as it idled funny +,-
> 300+ rpm, and I took the intake manifold off and had it tanked because it
> was just too dirty.
> 
> I did this also because the egr valve appeared not to work, and after seeing
> the egr valve passages from the outside all clogged, I just thought that was
> the problem.
> 
Better find some manuals.  EGR doesn't apply at idle.  If the EGR
passage is plugged, it won't affect idle speed.

> now with a clean manifold I think I see something else. this 'egr' manifold,
> has two small ports on the passenger side, that would appear to mate with 2
> ports on the head on that side. these ports are right under the egr valve on
> that side.
> 
Should be 1 rectangular hole in the center of each head, slightly
smaller then the pair of holes on either side.  This feeds exhaust to
the EGR.  I know which "ports" you're seeing.  They have no mates in
any engine I've seen.

> however there are no ports on either head for such a purpose, and no holes
> in the old intake manifold gaskets either. so even with the intake's egr
> ports cleaned up, nothing is going to happen.
> 
Not true.  Blow air through the holes under the EGR valve and see
where it comes out.  Block off your "mystery" ports when you do.

> so is this a clear case of a different set of heads/manifold ? or is this
> not a problem ?
> does anyone sell an egr valve block off plate ? I'd hate to kind of leave
> this condition existing as the egr passages are just going to load up with
> carbon again.
You'll probably have a better answer for this after you try the above
test.

> 
> also, in looking at the HP ratings for 350's around that time, (73), what
> happened to the HP ratings ? this engine would appear to have a hp rating of
> 145. the 350's prior seemed to have about 25+ more, was this a different
> method of measuring hp ? or was this the result of the emission requirements
> at the time ??
HP measurements went from Gross to SAE Net.  Same engine suddenly
rated "as installed" and appeared to lose power.

> 
> I accidentally got a set of felpro intake manifold gaskets that appear to be
> for a intake manifold that blocks off the exhaust crossover. I would guess
> that this was done to help cold running conditions, any advice on retaining
> this or not ?
Depends on your local climate.  Cold weather driveability is often
hampered by blocking exhaust crossover.  Some manifolds rely on the
hot crossover to open the choke.
> 
> thanks for all you're help. when finances and time permits I would just love
> to efi this.
> this is a 350 in a 72 xj6 with a turbo 350, I plan to put a 4 speed auto in
> it sometime.

You've got some learning ahead of you, by the sounds of things.  You
might want to bite the bullet and find a used v-8 TBI setup, so you
could be learning about a more current fuel system.  They're not even
teaching carbies in the trade schools anymore.
Also, you really should get a good reference manual for the carb if
you're going to stick with it.  You can spend lots of time "mucking
about" and never solve any problems.  I like "Rochester Carburetors",
by Doug Roe.
Good luck!
Shannen
>
 
> Ted Stowe