As to the exhaust manifold leaking, it is a common problem with the 460's.
I replaced the exhaust manifold gaskets (and inevitably some of the broken
bolts) on my current and last (I stepped up to the 6 liter diesel) 460 truck
4 times within a half a dozen years. The last leak I decided to live with,
it has had the same small leak for over 2 years...
The Sheet metal heat shields were one of the biggest contributing causes of
CRACKED exhaust manifolds on the 460's. When I was a teenager I worked as a
parts puller in a wrecking yard, about 8 out of 10 460/429 exhaust manifolds
had cracks under the heat shields. These were the ones I pulled off of
generally unmolested Lincolns and pickup trucks. The heat shield bolt over
the exhaust manifolds, using threaded studs in some holes rather then bolts
for the exhaust manifold. I would not bother to put them back on if I was
Thanks for the update! I have been debating with several other mechs, to
the cert. of the heat sheilds. To the time of this ex. leak, I was not
running any heat sheilds.I had discarded these years ago, then everyone
says You have to run em! This is my first leak since removal. I had
switched carbs 650 C- AFB to my stand-by Holley 500 V-S. I have
installed my afb again! Is it possible I was leaning out and running
higher temps pulling loads, and this made the gasket burn away? Would a
better gasket be calle for? What would that be? I used Fel-Pro or McCord
Would Mr. Gskt. Engine Works make a better Gskt. Being an old line
mech. I am thinking thickerer may be better, or Neo comp. Maybe some
other I have not heard of?
Numbers to You
I have not found a satisfactory gasket. I do know that I put 302 exhaust
manifolds on a Bronco metal to metal, no gaskets, fresh engine rebuild
against freshly milled manifolds and went well over 100,000 miles without
leaks or problems. But then again the 302 is not prone to exhaust manifold
leaks anyway... I will say double gaskets seams to exasperate the
On Mon, 6 Dec 2004 10:04:12 -0600, firstname.lastname@example.org (William
You may want to try Summitt Racing here on the net. They
have an 800 # there if you want to call. I think you may
find they have a copper or similar gasket may for
severe/racing duty that may be an improvement for you. If
they have them for this application, it will probably be a
good bit more expensive than regular gaskets. If they work,
the cost will be made up in replacement cost. The cracking
of 460 manifolds is common. There are a few aftermarket
replacements that may be better - just dont' know as OEM
parts are generally better - not always. The only solution
to cracking is headers but, they have their own problems and
are not usually preferable in MH apps. If you are
entertaining the idea of headers as a solution, you may want
to try Doug Thorley Headers - good quality - not cheap.
They have recently been bought by another maker but, at one
time, had a nice set of 429/460 headers designed for MH apps
to increase the mid range torque which would be a plus.
IIRC, they had both mild steel and stainless versions as
well as Jett Hot Coated available. The Jet Hot offers some
benefit in heat retention w/o heat shields. Gale Banks
Engineering may also be a source of help as they have done
extensive work with the 460 engines over the years. You
can also get a header insulating wrap from Summitt to
replace the heat shields on headers. I, personally, would
not use a wrap on a painted steel header because of the
possibility of collecting moisture especially on a MH that
may be parked extensively.
Are your manifolds leaking at the head or at the connection to the exhaust
pipe? If they are leaking at the "donut" gasket to the exhaust pipe, then
check for a missing liner (for lack of the correct term) that slides inside
the exhaust pipe, from the cast iron manifold, for approximately 3-4 inches.
This liner keeps excessive heat from burning out the "donut" gasket and
causing a leak.
If your manifold leaks at the head, check your gasket. The gasket may be
laminated and should indicate a head side and a manifold side. A laminated
gasket installed backwards (left side on the right side, and vice versa) may
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