Rear intake coolant bypass

I may have in correctly assumed this is a race only mod due to the T stat being by passed.

The hottest part of the engine is at the rear of ether cylinder head. Running 2 small lines passed the t stat is fine for a race mod. In the street, you would have to do research on how things work out and how hot & where.
You could introduce a restriction in the lines as not to circulate to much coolant in and out of the radiator without having sufficient cool down time.

For the street, I agree, under the T stat would be best.

I made a 1'' spacer out of a junk piece of alum. , and plumbed the lines below the thermostat, also ran them above ,which filled the block faster.
Dont remember which way I left them-----
the lines I drilled and tapped in between the 3/5 and 4/6 cylinders , were an idea I got from Bill Jenkins---------worked well !
I even thot about doing it on my 505 , but forgot it .