Yesterday I was lining up my head gasket with my heads and realized that there's a ton of little things that seem "off" -holes in the gasket that are too small or missing completely or slightly off center. I made a template of my heads' holes using a big taped down piece of paper and a crayon and then cut out the holes to lay on top of the gasket- I made marks with a marker on the gasket and the heads where I COULD "port" the gasket / heads for a better fit, THEN I found Felpro's article on the subject and now I have more questions...
http://www.felpro.com/technical/tecb...ant-holes.html

• How do you know that your heads and head gasket are a good match for each other?
• Felpro's article says that they intentionally close off a bunch of the holes or make them smaller in their gaskets to control the flow of coolant but they're generic gaskets and aren't made to work with particular heads. They also say if you cut / drill or port them you'll screw up the coating they put on them.
• Coated gaskets (See Felpro 1094 coated shim gasket): Should you still spray them? Felpro says that if the surface has a finish of RA55 or smoother, it does not need an additional sealer at all. If there are minor imperfections, use a Copper Coat product, and if there are more significant casting imperfections use a brush-type sealer.
• What block deck prep should you do that you can do at home to have the best chance at success? Felpro specifically says check the block deck with a straight edge. They also say to ensure that you DON'T do any side-to-side sanding as this opens up opportunities for leaks; sanding should be circular. -But how do you ensure the deck is still flat when doing circular sanding?
• What sandpaper grit is going to yield an RA55 or smoother finish? (Seriously, cheap *** hobbyists aren't going to have the equipment to check surface finish RA#s...)
• Recommended cleaning prep for the deck surface and the heads?
• How to apply the copper coat if you need to? Apply it wet or let it dry first? I assume spray and let it mostly dry then put the gasket on the block and then set the head on...
• Anything else people should know?

Thanks,
Adam

 

No joke....some of the guys on YB and ST prep the block with scotchbrite pads.

 

Adam,

As you know from the numerous discussions about my 355, I had the block and bottom end assembled by an expert in my area. I assembled everything else including installing the AFR heads to the cleaned block. My block was not decked which I specifically requested. NO DECKING of the block! If reasonably straight, I told the builder leave it alone which is what was done.

My expert builder told me to use the brush from aviation sealer on both the block and the cylinder heads. I then placed the Felpro 1094 gasket in place and tightened everything up using the GM torque sequence and procedure. I have zero leaks going into driving season #5.

 

Leave the Fel-Pro gasket passages alone. I suggest you find a copy of the performance gasket catalogue and read it. There are about 25 different head gaskets for SBC. The performance catalogue explains the differences. No where else have I been able to find comparison information.
RA55 is about 240 grit if you could call it that......but it is pretty shiny.......the only time I do not spray the gasket is on fresh milled block AND heads.......all others get Hi-Tack.
Spray it on while hanging from two coat hangers front and back........wait ten minutes and install. That's it.
Mr Gasket bought Corteco/Detroit gasket it seems and these pepper white gaskets are EXCELLENT for rebuilds if the surfaces are questionable......the sealant on the surface of these liquifies when torqued to fill imperfections.
Steel shim gaskets should ONLY be used with cast iron heads....and flat at that!
MLS gaskets are nice.....seal well and hold NOS to 250 hp + but are very pricey now......to the point where I will not use them unless specified.
The Fel-Pro block mod in their instructions for the 1010 gasket flatout works.....just do it. It cools a hot spot in the heads between the center two exhaust ports.......the restrictors in the gaskets redirect the flow to carry the extra heat away.......they did their homework.

Jebby

 

I installed my 1094 gaskets dry and haven't had any issues.

 

Thanks Jebby, that's great info!

The Felpro Performance Catalogue seems to be online now as an "E-Catalog" on Felpro.com and the physical catalog is a PDF here: https://fme-cat.com/digipubZ/Felpro-...-2018/#p=Cover

It does say that a Felpro 1094 works for aluminum or steel heads. I don't think I'm going to deal with getting to 240 grit surface smoothness and I have copper coat already so I'll go that direction, I think.

I'm going to go try and find the info on the Felpro 1010 gasket mod; not clear on whether it applies to the 1094 gasket, but I'm interested now.

I'm still not sure how to ensure a flat deck surface with just power hand tools, though...


Adam

 

I would use the head gasket that the aluminum head manufacturer recommends with NO modifications.

What heads are you using? I'm using the 180 AFRs. The recommended gasket is a 1003 Fel Pro. It's compressed thickness is I believe .041. I have considered going to a thinner gasket to gain compression numbers.

Craig

 

don't mod the gaskets,,fel-pro is one of the ''TOP'' gasket manufactures in the world,

use what they recommend ,put em on,and leave them alone

 

Felpro 1094 is .015 inch

 

 

Sorry it's a 1003 FelPro composition gasket.

I'll change my post.