What are you using for fan and shroud? High temps when slow moving and idling around is often a fan issue.
I have dual Flex-a-Lite fans with built in shroud stuck right to the rad....But that also might have to be improved....Since I bought those, I see they are making better fans....The rad is 19x31 and supports a pretty good sized fan setup. The BeCool rad is rated to 1000hp.....and I have it sealed to the front opening of the car. Almost all the frontal air has to go thru it. I think the fans were rated at 2500cfm back in the 90's when I bought them. With a core of 27x18, I could switch to the newer S-blade style and pick up 500cfm.
Ignore the injection...I took that off some years ago.
https://www.summitracing.com/parts/flx-490/overview/ My guess is that you will find( like i have) that your water pump is pumping plenty of water. My issue was not enough fan. That completely eliminated my street driving issues.
I assume you arent running without an obstruction to slow flow down( hogged out stat works good) running with nothing in the way doesn't work. Fan(s) that way wont have time to cool the water. It needs slowed down. so you can actually cool the water while its in the radiator.
When looking at fans i have found the cfm ratings very inaccurate, all over the place. If they aren't drawing a lot of amps, the motor isnt up to snufg. I have seen stuff they say is 3000 cfm and draws 7 amps. And a fan that draws 20 amps and is rated at 2500 cfm cools WAY better. More amps, more likelyhood the fan will cool well. More amps, better motor, better cooling, more money.
I like Derale stuff. US made, excellent motors. They make a dual fan 4000 cfm unit that is heavy duty
