Todds1987iroc

This is the same post from the TPI section if you did not see it there.

When installing L98 aluminum heads on a 305, do you just use regular 305 felpro head gaskets or what else is avalible? I read in the GMPP book that you should use a gasket with a stainless steel fire ring with these heads. Is this true? For those who did this swap what did you use?
How much of a problem is the EGR hook up with these heads? I have to have the car emissions tested this year and want to pass. what is the best or easiest way to hook it up and work?
Some of the mods on my car right now are a Hypertech thermomaster chip, MSD coil, ACCEL distributor module, cat back exhaust system, 1.6 ratio rocker arms, and K&N filters.
I am new to this message board and appreciate all the help that is given.

Vader

Todd,

Aluminum heads should get a steel-lined gasket, but then most cast iron heads get the same thing if the gaskets aren't the absolute cheapest. Most decent head gaskets have a flattened soft steel wire in the laminated steel core.

If you use a Lock-wire gasket, you'll need to machine a groove in the head to seat the wire.

Incidentally, the L98 heads are not necessarily the best choice for the 305 engine. Port sizes are much better, but the larger combustion chamber volume will reduce compression unless you install domed/wedged pistons. I suppose you could mill the heads about 0.100", but the valve clearance would be dangerously close to the minimum. In addition, the larger (1.940" intakes will fit in the cylinders on 305 heads, but not necessarily on the 350 heads since the center spacing is slightly larger. The valve faces might interfere with the cylinder deck. Whatever you decide to do, trial fit a head and check valve clearance before you button it up permanently. If the clearance is inadequate, you'll be taking it apart again (or picking up the pieces) in the near future.

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Later,
Vader
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"I cannot take this any more... Saying everything that I've said before..."
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Guest

"but the larger combustion chamber volume will reduce compression"

Aluminum L98 heads are 58cc, so there isnt any compression loss The valves clear fine too, ask Willie, who has them on his 305. IIRC you have to use the 350 head gasket, that is something that should be in the archives somewhere.
As for the EGR, the only way to make it work is to run an aftermarket or vette base, and run a tube from the RH exhaust into the rear of the intake where there is a inlet port for the EGR on the manifold. There is no way to make the heads themselves work with the EGR.

Vader

Oops! Missed that one...(DUH!) The aluminum heads also have a slightly better flow and port design than that of their iron counterparts.

Thanks for catching me on that, Max!

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Later,
Vader
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"I cannot take this any more... Saying everything that I've said before..."
Adobe Acrobat Reader 4.0