Head Gaskts

[77JimmyMan]

The time has come to upgrde the original motor in my truck. Theres only around 89,000 miles on the beast so im not doing a complete rebuild, rather just redoing the top end; heads, cam, intake, carb. After pulling the heads I found that thin metal head gaskets were on it. I have both a set of the metal ones and felpro stock 350 replacements(regular gasket style). The felpros are about double the thickness. With the new heads compression should bump up to around 9.5:1 (64cc chambers VS 76cc) so I dont think compression is an issue. What I was wondering was if there was any difference between the gaskets? Is one better than the other? Any input woul be great.

 

[prjt_blzr]

I ran the thin metal gaskets on a 289 mustang a number of years ago. They are great for boosting the compression just a little. They also can be difficult to get to seal properly. If you have enough compression, I would use the good old Felpros. They are almost fool proof to install leak free.

 

[BorregoK5]

Your concern should be less focussed on compression and more focussed on the "quench" when decidiing on a gasket. If you look at your chamber on your new heads you'll notice that its a half circle open chamber. The closed half of the chamber (flat with the head) and the piston come in close proximity to each other and create turbulence, assisting in the burn process and helping to cool hot spots. Assuming you had a .000 quench without a gasket meaning that the head and the piston make physical contact with each other at the pistons fully extended stroke, then you would want to run a .035" gasket to acheive an ideal quench. Too little and you might make contact, too much and it decreases the cooling effect. You'll have to measure your piston to head clearance as the .000 is just an example. The copper gaskets are available in different thicknesses to get it exact while the generic felpros are just an educated guess. Copper has heat transfer qualities which can be desireable as well. The biggest issue with the copper gaskets is that they do not deal well with imperfections on the mating surface like the felpro style gaskets which conform to flaws (small ones that is) so only use copper on a well prepped surface. Hope this helps.

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