I received lots of responses to my should-I-have-larger-valves-installed
question. Thanks to all of you who took the time to respond to that
question and beyond. Recall I was asking so that I could decide on
whether or not to have the valve cut-outs in my flat-top after market
pistons enlarged. A couple of people suggested the obvious: have the
cut-outs enlarged and worry about the valve question later. That made
so much sense, I got on the phone right off and gave the okay to my
rebuilder to do just that.
As for the larger valve question, as several people pointed out,
unmodified HiPo 289 heads are getting hard to come by; better to screw
up some less rare/valuable set of heads or go after-market. I'm keeping
the unmodified heads as is. The other set I have already has larger
valves and has had some chamber and port work done to them. Assuming
they are usable, I'll keep them around for swapping with the stock heads
if I decide I want a little more power later. Or maybe I'll start with
them and fall back to the stock heads if I don't like the results.
Several people suggested replacing my street radiator with an after
market aluminum rather than having the original recored. A couple of
thoughts on this: 1. This means a mix of cast iron and aluminum, which
means the potential for damage due to electrolysis. In this case, the
aluminum is the metal that would suffer the serious damage. I've
already experienced this to some degree with the aluminum water pump,
the thermostat inlet and an aluminum Tee. The Tee is beyond salvage.
2. Some early street Cobras did have aluminum cross-flow Harrison
radiators and the spun aluminum header tanks. Shelby dropped these
early on because they didn't hold up very well. I'm assuming there was
a reason for this then that might still apply today. My plan is to use
distilled water and anti corrosion/lubricant additives rather than
glycol based antifreeze to improve cooling.
Here are a few other things about the engine's setup I didn't mention in
my original post in case anyone is curious:
solid lifters
hi-riser aluminum (original Cobra) intake
715 CFM Holley
Thanks again,
Roland
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