High Temp's with SL/6 (.060 oversize)

Syleng1 said

0.060" over size is not the issue. Especially at drive way idle.
Timing - as said before.
Radiator clogged- as said before or too much paint on fins? It takes a lot to over heat a /6/
Lower hose clasping (is no spring internally) When free revving in driveway does the lower hose suck together?
Engine running lean? possibly.
Fan belt slipping?
Exhaust clog? (stretch but has happened)
use an external gauge besides a heat gun. I've seen those fail as well. Especially Harbor Freight ones.
Not much more externally- you may have a bad thermostat. Chinese junk made for a lot of them; it could be stick at idle water flow but opens a bit when driving and more flow from water pump forcing it open.
Keep us posted on results.
Joe

Click to expand...

[SOLVED]...It's the Radiator
Early results show TEMP at mid-range and staying at this level after 30-45 mins driving at 40-50 mph plus stop and go traffic. I also installed a new t-stat (180 dF) from O'Reilly (MURRAY Ultra and made in Israel). Now some fine tuning on carb and back to org rad w/ OEM p/n. Rad on-board has been re-cored but a/t lines are totally realigned and lots of tension.....not good. Will ck temp's today at rad TOP and BOTTOM but return hose to water pump "icy cold"....this is good.

It could have been the t-stat but I have had 3 installed...all from NAPA. Dwell is at 41 deg, timing at 0 TDC, will adjust to 5 BTDC based on consensus of forum. Idle at 700 rpm, must ck a/f setting, plugs appear rather "rich", not healthy "light brown". Plugs are Autolite 66. Valve lash set right on at 0.010 IN and 0.020 EX when hot. Total mileage after rebuild less than 500 mi and engine started in 2014, built in 1995.

thx for recommendations, suggestions, and "things to try" for overheat issue. All were helpful. Long live SL-6s and Dodge Darts