@71Polara383 managed to convince me that, while Medina's engine was out to fix a couple of small(ish) but annoying leaks, we ought to clean it up and repaint it. The process is now underway.
Now comes the question of choosing a paint brand and shade. After reading various board posts and talking to some members, I first narrowed the choices down to Duplicolor DE 1631, VHT SP126, and Bill Hirsch Chrysler Blue (BHCB).
I bought cans of the last two. Here is a photo (courtesy of Wyatt) of what the SP126 and BHCB look like in natural light (BHCB is on the right, clearly more blue).
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Here is a second pic, showing the two-tone fresh-paints intake next to Medina's engine (after some cleaning up by Wyatt, but with original paint). BHCB is on the left in this picture, SP126 on the right. The Gates water pump, painted using locally-sourced off-the-shelf paint in what was sold as Chrysler Blue last year, is too dark to my eyes and will be repainted this time around.
Edit: Wyatt found the (now almost empty) can he used last year, and he says that the water pump was painted using Duplicolor DE 1631.
Looks like the VHT is a pretty good match for the original engine paint as it looks like after 50 years of fading, BUT not a perfect match as one goes toward the bottom of the engine (which is at the top of the picture):
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Here is a third picture, this one taken inside, comparing the VHT and the original -- as seen at the top of the engine (not the pan).
View attachment 371873
The problem with matching a 50-year old paint is of course that, with heat cycles and grease drips and all, the original paint must have lost its original shade. Indeed, an uneven discoloration pattern is seen in this fourth photo, which Wyatt took a couple of weeks back -- before some more cleaning. It shows how the original paint has become much greener (turquoise, VHT SP126 look) at the top due to grease/heat, whereas the bottom looks much more blue. The VHT can be seen in the area
circled in red.
View attachment 371872
Hirsch lists its blue paint as OK for all Chrysler engines from 1973-1983 and for 318 engines in 1969-1972. Its web site states that turquoise is the right choice for 1963-1971 BB engines. Color change charts I have
read, though, show a switch to Chrysler Blue for T-code engines in 1970 -- but my engine was built in the 29th week of 1970.
View attachment 371863
What to do?