19X31 aluminum crossflow 2 core radiator (at least 1" core width), two SPAL electric fans, both pullers or one pusher and one puller, depending on fitment issues, 160 degree thermostat with four 1/8" holes around the periphery, and a CVR 55 gpm water pump.  Cools my big SOHC in the race car on Drag Week, never see over 180 unless I'm leaking coolant without knowing it.

Years ago Meziere told me that my 650 HP FE needed a 55 gpm water pump to keep it cool on the street.  If you are approaching that kind of power, I think you need a higher flowing pump.  Also, a duplicate of the factory radiator in aluminum sounds like a weak spot to me, you could probably use a bigger crossflow.

A lot of people have trouble with the engine getting hot at idle, and then cooling down at speed.  This is usually the factory water pump turning too slowly at idle.  Conversely, it is also common to have decent cooling at idle but overheating going down the road; this is usually the radiator being too small, plugged up, etc.

I'm thinking that you may have both problems since you are seeing cooling issues under both conditions.  However, bear in mind that even 220 degrees is not really that hot; as long as you are not spitting coolant out of the radiator, you probably aren't hurting anything. 

I wasn't making my intake adapters when I did the dyno testing for the book, so its not in there.  But I have heard from several folks who run them that they really work well, although the Edelbrock 2863 manifold with the Dominator flange is even better.  Note that the 2991 intake has to be machined to fit my intake adapter, and you have to have the Yates style adapter (part number 13006), not the standard 13001 adapter.  Also, some port matching between the adapter and the 2991 intake is required.

Mike, thanks for the offer but in the meantime this guy has switched to titanium valves and better springs.  He is also going with a set of my non-adjustable rockers, which is the right choice with titanium valves.  I think his odds of surviving at 8500 are a lot better with this combination.  We will see...

Sorry if this has been covered and I missed it, but if he used a sleeve to calibrate his sonic checker, that will not be accurate to check the bores.  A sleeve is a much different material than a cast iron block.  My sonic checker requires that you select the proper material for an accurate measurement; mine says to use the grey iron setting for cast iron blocks.  Check calibration on the rear block rail, as Ross suggests.  If the transducer is curved it won't matter, as long as the transducer is held at a 90 degree angle to the flat surface.

Merry Christmas to all my pals on the FE Power forums!  Looking forward to lots of good information next year.

Arched guides per se are not really the issue; as I understand it they are used on modern engines because the guides have tensioners attached to them to keep the tension on the chain constant.  A straight guide can't be used if the guide is going to be moving around from a tensioner pressure.  So really the main issue with the SOHC secondary chain drive is the fact that chain tension can vary with temperature, RPM, load, etc.

Having said that, as a guy who has been running these engines for 20+ years, the chain drive as-is is not really a problem, as long as you tension the chain correctly, go easy on the engine until it is warmed up, check the chain tension periodically, etc.  But it sure would be nice to have an automatic chain tensioning system on the SOHC.  I know someone who is working on that...

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