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lanteau
02-15-2010, 02:56 PM
I'm currently torn between what head gaskets to use on my 90 SC. I am having the heads machined, but I am not going to have the block machined. Because of this, I'm starting to lean towards the standard composite gaskets instead of the coated mustang MLS ones. I will be using ARP studs. My car is very mildly modified, 10% OD, exhaust, IC fan. Can I expect the composite to hold up another 100k miles? It's daily driven, an occasional race against some ricer on the street and an occasional 1/4mile drag night in the summer.


Part Numbers I'm looking at (are they correct?)

Composite:

9642PT-1 (the same for both sides?)

MLS:

9262PT and 9263PT

David Neibert
02-15-2010, 03:28 PM
For the mods you have, I'd just use the Felpro composite gaskets (yes same gasket both sides).

David

lanteau
02-15-2010, 04:22 PM
Yeah I was starting to think that. Plus the machine shop I'm taking the heads to just does a milling job so I was told the RA would be around 90-100. MLS on that sounds risky. Composite should seal it up fine, I think I'll install them dry without copper spray too.

frdlvr30
02-15-2010, 08:00 PM
I would go composite on that application. With the ARP studs it will be plenty...

decipha
02-15-2010, 08:41 PM
not me, I just don't feel safe with composite gaskets, out of my 6 supercoupes only 1 doesn't have mls gaskets and thats my blue 92 5spd that i bought 2 weeks ago, 66k miles all original on stock gaskets, not for long though, i already swapped in a BHJ the DAY I bought it, I even bought a set of mls gaskets, arp studs, and everything else to do the head gasket swap last week.

Also note, the mls gaskets for the 97 f150 4.2L will work as well and they are cheaper, $45 from autozone.

felpro right side #9253PT and left side #9250PT

don't forget to drill out the bottom center rivet

XR7 Dave
02-15-2010, 10:07 PM
Also note, the mls gaskets for the 97 f150 4.2L will work as well and they are cheaper, $45 from autozone.

felpro right side #9253PT and left side #9250PT

don't forget to drill out the bottom center rivet

They work, but the coolant passages are wrong. I recommend only to use the right gaskets to maintain the OE designed coolant flow through the motor.

T-bird4vr
02-15-2010, 11:40 PM
Yeah I was starting to think that. Plus the machine shop I'm taking the heads to just does a milling job so I was told the RA would be around 90-100. MLS on that sounds risky. Composite should seal it up fine, I think I'll install them dry without copper spray too.

That is probably what the finish was on my heads when running the mls. They are good for 50k and around 15k with 20+ psi.

decipha
02-15-2010, 11:46 PM
x2 that is correct although i wouldn't say wrong perhaps different

the 9253 and 9250 gaskets has bleeders where the others don't

for this exact reason is why it was appealing to me


They work, but the coolant passages are wrong. I recommend only to use the right gaskets to maintain the OE designed coolant flow through the motor.

XR7 Dave
02-16-2010, 08:28 AM
That is probably what the finish was on my heads when running the mls. They are good for 50k and around 15k with 20+ psi.

Not likely. 94-5 motors were decked 2x at Ford in an effort to improve head gasket performance. Those motors have a very good finish on the decks, probably in the neighborhood of RA 50 or better. I have not seen anyone deck heads to RA 90, that's f-in terrible. We deck both our heads and blocks to RA 15-25. What are they using, a cheesegrater??? Find a machinist with modern equipment.

XR7 Dave
02-16-2010, 08:35 AM
the 9253 and 9250 gaskets has bleeders where the others don't

for this exact reason is why it was appealing to me

Also the exact reason not to use them. The 9253 gaskets were made for split port heads which have different cooling passages. By adding bleeder holes you are changing the water path through the motor. SC engines are notorious for not providing enough cooling to the rear cylinders and the lack of bleeders in the front will exaggerate this. This doesn't mean that you will blow gaskets or anything, but it's like those EEC changes that you make without knowing all the impact of what you are doing. Sometimes common sense logic doesn't apply due to parameters that we are unware of. So before you change something, and recommend to others that they also change it, you should be sure that you know the implications of what you are recommending.

Fords reliability testing goes way beyond what yours or my experience will ever teach us. Some things are best left alone and I believe the head gasket coolant restrictors are one of them. If Ford could have gotten by with only one part # for the head gaskets, I'm sure they would have done so but they didn't and I'm confident they had reasons for that.

burzum10
05-21-2010, 06:21 PM
So are you guys suggestion for a relativly stock set up just to stay with the stock head gaskets? I have mustang block with mustang heads 93 m90. after reading the service procedures for using the mls gaskets I am now leading to the super coupe gasket or the stock mustang gasket.

What would you guys suggest? I am changing my head gaskets soon and would like to get some opinions. I do not plan on doing anything else to the engine. i am running the stock pullies.



Douglass