Michael,
The May 1996 issue of Muscle Mustangs & Fast Fords carried an article
comparing the Twisted Wedge TFS, Edelbrock Performer, and SVO GT-40
aluminum heads (reprinted in the Summer 1996 Tiger Press). All of these
heads produced very close to the same output numbers, with a slight edge to
the TFS's. These heads have 60-61 cc combustion chambers and I've heard
they sit a bit higher than the stock cast iron 289 or 351W heads, which is
an issue in for the cramped Tiger engine bay. But, at least the TFS heads
can be milled up to 0.180" to increase compression and decrease height.
Because of the extra heat loss in aluminum versus iron heads, you can run
slightly higher compression with aluminum. Maybe half a point I would
guess; e.g., 11.0:1 vs. 10.5:1. The TFS heads have 2.02" intake valves
versus 1.90" with the Performer and GT-40 heads.I would imagine any milling
of the heads would require you to fly-cut more relief in the pistons,
especially the TFS heads with the 2.02" intake valves.
The thermal expansion differential between cast iron and aluminum is
somewhat problematic. For example, if you use solid lifters, setting the
valve lash is harder to do. With cast iron heads you can even set them
cold. For around $1,000 fully assembled, any one of these heads is hard to
beat. I spent a lot more than that for the work on my 351W heads. And
saving 35 or so pounds of weight is a big plus too. I'm interested to hear
what others have to say, but if it were me, I'd buy a set of TFS or
Edelbrock heads instead of spending the same kind of money for machining a
set of cast iron heads.
TTFN,
Bob
At 06:51 PM 8/2/99 -0700, Michael M. Kelly wrote:
>Anyone out there have any experience with aluminum heads on a Tiger?
>Superior
>performance and weight savings would seem to make them a natural for our
>cars
>provided they fit without modification and don't induce any more cooling
>problems
>than we already have. Any arguments for or against would be
>appreciated.
>Michael
Robert L. Palmer
UCSD, Dept. of AMES
619-822-1037 (o)
760-599-9927 (h)
rpalmer@ucsd.edu
rpalmer@cts.com
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