Tom,
Is the entire engine block thermally stable in the field, under load? One of your challenges (with proper gap) is addressing the Delta T, cylinder to cylinder. What is the coldest temp the coolant will see, in the case?

Bob

Does rigidity of the cylinder bore play a part in ring gaps and thermal expansion? In otherwords, would you be following the same guidelines for a dart big m 4.500 bore block as you woukd a 35 year old 454 production block that's been bored once or twice ? As far as expansion rates are concerned and maximum ring seal to bore ?

I'm not sure that I know how to answer this one, Bob. How would I know if it's thermally stable? What factors would determine that?

Nothing colder than 55 degrees, though that would only be coming out of hibernation with testing. Our water temperatures typically warm to the low 60's in the ocean by May with higher temps on the ICW and Bay (and for the most part, I like to stay on the ICW until it's warmer anyway).

Does that answer the question?

They are good rings. Use them in all the motors I have except for those damn stroker pistons in my 496 that require a super expensive rings for some reason.

Tom,

The delta between the water entrance/exit temp. The dimensional change in bore diameter on a 4.250" bore between 60º F and 210º can run from .002125" - .00425", depending on a number of factors. That can be exacerbated on a cylinder to cylinder basis based on localized temp variances in a thermally unstable block.

Bob

Why should you not run a thermostat in a blower motor?

Some feel that running the engine colder will help prevent detonation.

Ok, thanks. I could see that. But Let's say a low compression (8:1)454 with a 250 blower and sufficient amount of fuel being supplied with a 140-145 degree thermostat. Would that still be hazardous to possible detonation?

Yes Mild... think about it... when you have lets say a 454 with a bore of 4.310 for eg, the cylinder wall thickness (thinner) will have a significant effect on (friction surface temp) the wall's ability to cool... as opposed to lets say a dart/merlin 4.500 bore (thicker sleeve) temp is stable all around the bore and cools evenly and effectively... if I'm understanding your statement correctly???

Bob what I've been doing for years to address front to rear temp differences is bleeding off the rear ports of the intake manifold thus evening out the temp from cold front hot rear... which is a common issue with BBC