perf-list-digest Wednesday, October 28 1998 Volume 01 : Number 130

Ford Truck Enthusiasts - Performance
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In this issue:

RE: FTE Perf - Toughy
FTE Perf - Jeep/289/302
FTE Perf - Re: Toughy
FTE Perf - Motor Mounts
RE: FTE Perf - Re: Toughy
FTE Perf - Toughie
FTE Perf - Fwd: Can U Help Me!



Date: Tue, 27 Oct 1998 10:32:16 -0500
From: Sleddog
Subject: RE: FTE Perf - Toughy

i think the problem is, that the current deck height is unknown.


- ----------
From: George[SMTP:mega55]
Sent: Monday, October 26, 1998 9:23 PM
To: Ford Truck Performance List (E-mail)
Subject: FTE Perf - Toughy

I'd try that before I went to the trouble and expense of blueprinting the
manifold to the heads. If that doesn't solve it or you want to blueprint
it, please post the deck height and type of manifold.

George Miller

This is for all you Smarties :-)

About 10 years ago my dads 429 was rebuilt, and the machine shop decked the
block for more compression. He also ground the intake manifold to match.
Well, a few years later, we replaces the manifold and have a vacuum leak
since. My question is if anyone knows a way to tell how much to machine
new manifold so it all fits tight again. Any help is appreciated.

Darrell Duggan
74 F-350 "Tweety"

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Date: Tue, 27 Oct 1998 11:17:35 -0500
From: am14
Subject: FTE Perf - Jeep/289/302

Don Grossman. I'm certainly no expert on the small blocks, but this is
something I have always been told. The early 289's and the late 289's had
different bellhousing bolt patterns. I have no idea when they changed, but
I'm pretty sure they did change. Just be sure the bellhousing in the jeep
will mate to a 302 before you purchase.

Ardmore, Al.

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Date: Tue, 27 Oct 1998 09:18:21 -0800
From: "Chris Samuel"
Subject: FTE Perf - Re: Toughy

If you know the deck height then you can simply calculate it as George
pointed out. If you don't you will have to do some measuring to figure out
where to cut and how much.
But first I would verify that the manifold is not warped or cracked with
that causing the leakage; and that it was installed perfectly as it does not
take much to fail a gasket seal.
Then I would clean the top of the engine block/heads and set the manifold in
place without the bolts and simply look at it and see if you can simply
observe any gaps; dental mirrors and strong flashlights help. I have even
put the flash light in the valley aiming at a specific spot to see if the
light leaked out. Then I would put the bolts in just enough to have them be
there and see if possibly one or more of the bolts is causing the manifold
to move; if so have the bolt holes moved (slotted). This is an often
forgotten step when the manifold is machined. (I suppose that I should point
out that there must be a gap between the block and the manifold, that it
must be sufficient for the manifold to be torqued down on the heads.)
Odds are that you will find the problem with those simple steps but if not;
get some non-drying "Prussian Blue" at the auto parts store and lay down
thin strips of this nasty stuff. Down the intake flanges top and bottom and
both sides of each of the ports. All so across the front and rear of the
block if you think that you have contact there. Vary carefully set the
manifold straight down on the engine and then pull it straight back up; I
hope that it is an Aluminum one:)
Look for even contact in the Bluing. If you did not touch there will be
none. If the manifold touched hard the bluing will squish out of the way.
What this will tell you is not how much but where your contact points are,
once you know where you can then make educated guesses as to how much to cut
off and where.
For me I simply go to the mill and take say 0.005 to 0.020 off and then test
the fit again, repeating as many times as I need to. But this could get
expensive as most of the time in this job is in the set-up.
So the next step is to see if you can measure the areas that the manifold is
in no contact at. Once you know where the contact points are clean
everything up. Now you know why I said it is nasty stuff!-) and reinstall
the manifold. Next using feeler gauges you attempt to slide them into the no
contact areas. You must be careful not to lift the manifold on one side and
lower it on the other; multiple set of feeler gauges are nice here about 4
works for me, but it can be done with one and care (take it apart so you
have loose blades). You are not looking for exact numbers only the trend.
For example the most common situation is that the manifold is sitting down
on the front and rear valley seals and not or just barely touching on the
intake gasket surfaces. In this case the manifold is going to be machined at
the Valley rails and by a bunch. How big the gap at the intake surfaces is
only indicates how big the bunch is but the exact number in the bunch is not
too critical as you will seal it with that bead of silicone. You can get an
idea by the stock specifications and the cut chart that is found in any good
shop manual.
Sometimes the cuts on the manifold are not parallel front to back and here
again the amount removed is not critical as long as it is not excessive. But
anytime that material is removed from the intake surface the gap at the
valley seals must be re checked.
The worst case is where the gap tapers along the intake surface top to
bottom or the other way. Say it contacts at the bottom and has 0.010 at the
top. this indicates that somewhere, sometime, someone, Chevroleted it all
up! If you do find this you best bet is to take the nice clean engine to the
machine shop and let them fit the manifold to the engine assembly. Then
record all of that data and never change the manifold again!( Or remachine
the whole engine and I'll bet that there are other errors just waiting to be
There are a bunch of ways to do this job but I have found that this is one
of the easiest. You can take your measurements and Trig. out the numbers to
tell you "exactly" how much to machine off but it really is not necessary on
a street engine; you only need to be close enough to have the gaskets seal
and there is generally a lot of compliance in the gaskets. Enough to
compensate for your fudging here and there a little. The angles must be
right though and that is why I recommended that the engine go to the shop if
you find that type of error.
On a race engine this must be perfect. Not due to the sealing issue but due
to port alignment. If the numbers are off there will be a step in the port
at this joint and that will cost power.
If this is a performance engine then this would be the time to match the
ports at the head and manifold. You can get a rough idea what areas are off
when you do the Bluing step. Remove any material that hangs out into the
port and you "may" notice a "slight" power increase. Don't forget to trim
the gasket if it hangs into the port.

Have fun.
79 Bronco

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Date: Tue, 27 Oct 1998 12:46:21 -0500
From: "Bruce A. Ramirez"
Subject: FTE Perf - Motor Mounts

Hi all,

I have a 1991 F-150 XLT Lariat 4x4 with a 4.9L and a 5 speed which I
bought new. In the last 7 1/2 years, I have had to replace the right
motor mount 3 times and the left motor mount once. Does anyone know why
they keep breaking? I'm not hard on my truck. The motor mounts are the
oil filled type. Does anyone make a solid rubber or heavy duty motor
mount for my truck?

Bruce Ramirez
1991 F-150 4x4
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Date: Tue, 27 Oct 1998 13:52:58 -0500
From: Sleddog
Subject: RE: FTE Perf - Re: Toughy

ok, my pulling engine i have a set of heads, and intake that were PERFECTLY
matched on the previous owners block.

i went to assemble (believing that our deck heights were the same) on my
block only to find that mine was appently lower.

looking into the off POS intake (is that port-o-sonic? or piece-o-crap?) i
could see the small blue line of the gasket at the top of the ports and the
bolts where very hard to get in. ended up torquing the intake down in a
"random" sequence. i really wanted to get this thing going and pull.
assumed that i'd have vacuum leaks, and hoped i wouldn't. small pwoer
loss at higher rpms where no bother to me at this point.

assuming that there was no more than .015 difference in deck height was a
bad thing i guess. measured mine when i ordered the stroker kit - it
measured 10.310 IIRC. couldn't measure old block - it had already been
redone (big hole in side being fixed.)

so, figured i'd run it like this till next teardown. anyway, been thinking
on how to know how much to remove. or, should i wait till i get my SVO
block and deck block to what i need for heads/intake match? hmm. how do i
do it either way.

so far, no vacuum leaks that i can tell BTW.

because of the small amount of material left in the intake, and the heads i
don't want to match them again after milling anyway. the intake is already
all epoxy'd up everywhere from the carb to the head. grinding any material
out could be cause to redo the whole thing! these runners in the intake
flow within 2% of each other and i don't want to start over again. i can't
afford the flowbench time that the previous guy had into it.

i guess the whole point is, i am impressed that there are no vacuum


- ----------
From: Chris Samuel[SMTP:fourmuelz]
Sent: Tuesday, October 27, 1998 12:18 PM
To: Perf-List
Subject: FTE Perf - Re: Toughy

major snippage of good original post-------------------------------------

On a race engine this must be perfect. Not due to the sealing issue but due
to port alignment. If the numbers are off there will be a step in the port
at this joint and that will cost power.

Have fun.
79 Bronco

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Date: Tue, 27 Oct 1998 11:27:26 -0800
From: "J.S.H."
Subject: FTE Perf - Toughie

" we replaces the manifold and have a vacuum leak
ever since"
Could the manifold be cracked or warped? We had a 78 W/460 at
work that always ran like like ! $%&.The mechanics were having fits
everything checked out fine,finally they replaced manifold and now
it runs like a Ford again.
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Date: Tue, 27 Oct 1998 23:21:17 -0500
From: Ken Payne
Subject: FTE Perf - Fwd: Can U Help Me!

Forwarded For: Susan Kerr
Please send replies to bkerr, not to the list.

Dear (person who gets this letter),

Ok, I know this is going to sound stupid if you have no idea what I'm
talking about. Please bear
with me. On CMT, they mentioned a contest that Ford is putting on. I
think you write different lyrics to Alan Jackson's song, and if yours
gets picked you win something. Well, seeing how you guys are Ford
fanatics, not that I'm not, I was wondering if you happened to know
something about it. Where you send the lyrics, what you win, if its
even still on. Now, I don't know if I sent this to the right spot, if
not please forwarded to someone who might know.
I've already tried to contact CMT, and they are no help AT ALL. Not
that I hold that against them. Ok, anyway, I would really appreciate
your help, if you know anything.

Thanx a bunch,

Yours Truly,


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