mummert aluminium heads for y block

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oldngrumpy

Junior Member
Hi guys,

just wanna get the opinion of anyone running these mummert heads on the street and whether the price is justified in the performance. Ive heard varying increases from 50-75hp. I see Ted Eaton has tested them with a variety of carb set ups, has anyone tried them with a supercharger? Are they ready to run right out of the box ? Any insight is greatly appreciated.

Regards
Rob
 
At what RPM do they start to outperform stock heads? Do they need a hot cam to realize their potential? Will they do any good if you use the stock '57 4 bbl. intake?
 
I've got a set on a 292 with a 312 crank, offset ground for 320 cid. Like any other engine parts, they've got to work together. The main thing I'd watch just changing the heads is the chamber volume/compression ratio. I pulled a set of Mummert ported iron heads IIRC, 471 castings, and put the aluminum ones on. The static ratio went from 9:1 to a bit over 10.5. That meant the 5# boost at 5000 rpm blower had to go. The flat top pistons, at 0.00 deck, didn't leave a very good quench area.

After a cam change to move the dynamic compression ratio down, and ceramic coating on the piston tops, we pretty much solved the quench problem.

The motor has FPA headers. 2 1/2" exhaust, and an older Blue Thunder manifold. I didn't have an engine dyno available, but the car runs better than it did with the supercharger.

The best info, as state above, can be gleaned from Ted's site.

http://www.eatonbalancing.com/blog/category/y-block/

I'd do it again, in an instant, but best on a full rebuild where you could dial in the Pistons a little better. I just couldn't bring myself to toss a set of custom pistons from the stoker kit, and spend the money to replace and rebalance the whole lower assembly.
 
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