Tricky problem from 1000 to 2000 rpm. Need help driving me insane.

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I got one of my best buys ever because the PO had put one of the head gaskets on backwards on a 351 C. He was a professional race car driver in California and he had his pit crew build his engine. He bored it .050" over and put flat top pistons in. Of course with one of the head gaskets backwards it would blow coolant out when you shut the engine down. He parked the car for 25 years in California and decided to get it out of the garage. The first time I drove it I knew was a backwards gasket and looked with a mirror and the R.H. was wrong. I used FelPro and have had no issue in about 3 years now. Can drive in 90 deg. plus and us AC withj now issue. 

The gaskets will have FRONT stamped on them but people tend to put the mfg. logo up so one will be wrong.

When I worked in race shop back in 60's and 70's my boss loved to build engines and not even put a head gasket in. Could get 16 to 1 compression and stay together. They sound totally different. You have to lap the head to the block they are as smooth as glass. Also have to epoxy off some of the water ports. I have a friend that runs 18.3 to 1 today on his car. He is going to sell after running it for 35 years. He has about $140,000 in it was the fastest 1966 GTO in world for years. It just cost too much to run burning 5 gallons of special fuel per 1/4 mile pass.

 
So things I've learned....

1) do not use coppercoat or any additional sealants when using newer Fel-pro head gaskets with permatorque coating. It caused leaks between almost all my cylinders in less than a year. 

2) Fel-pro Printo-seal intake manifold gaskets SUCK.  The seal around 3 out of my 8 intake ports failed. Each failure was due to a split along that blue "seal." This is an obvious weak spot.  I have no idea why they would have failed. 

3) Mr Gasket intake manifold gaskets aren't that great.  Mine came out of the package with tears and they were essentially brittle cardboard.  SCE gaskets are significantly higher in quality, really glad i ordered them, thanks Chuck! 

Hopefully will be firing her up today. Tuned the carb back to stock. Look forward to seeing if all my previous issues are resolved. 

 
Glad you like the SCE products. They also come in various thickness for custom builds/needs. I hope all goes well. Let us know. Chuck

 
ianpala,

          The close-up of the underside of the head shows, what appears to be remnants of a Fel-Pro blue Permatorque gasket, which has been copper-coated. Generally, copper-coating isn't done on composite gaskets, although you could, but in the normal world, head gaskets just go on as -is.  Is there an issue with either the heads or the decks not being flat? That's the only reason I can think of why someone would coat the gaskets, even though it would only be a band-aid to do so if the surfaces aren't true. 

 
That is a new one for me never heard of a rethreading tap. Taps are sold in GH sizes. Each number in the GH is .0005" over nominal. When building tools and heat treating steel that can change size we used GH 5 usually or .0025" oversize. I always cut a couple more threads deeper when I run tap in to be sure it is deep enough. I blow out and I do this before block is cleaned. So most of my taps are GH-5. I do not feel them cutting anything until they get to the bottom. I always use 2 flute taps much stronger. 

 
Well.... put her all back together and she ran super strong. And then she didn't. It's looking like either my lifter has collapsed or my cam lobe has gone flat on my Cylinder 4 exhaust valve for no good god damn reason. the rocker came loose twice and now I'm having to screw the nut all the way down practically to get 0 lash (adjustable valves with screw in studs). Only good sign is that the lifter doesn't seem to be pumping up bc when i press the pushrod down i can push the lifter spring down easily.   If it turns out being the cam... I'm probably going to look into a rebuilt bottom end so i don't put in all that work on my original.  Either way gotta pop back off the intake. This sucks 

 
If it ran "super strong" I doubt a wiped cam lobe. Hopefully you are lucky and it is just a failed lifter. Chuck

 
There are not that many sizes of bolts in a Mustang you can buy good taps for less than the whole kit. It does have a couple thread files. If a fastener is bad you do not want to put it back in just get a new one. The tapped holes you cannot get a new one so taps are more handy than dies or files. 

 
Pull the oil filter, dump it out, cut it apart, if it's the lobe wiped out there will be metallic particles in the oil, will look kind of like metallic paint when you look at it in the light.

 
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