Hey Moparts Techs, I need some professional assistance with a cooling issue I am having.

I built a 408 stroker 2 years ago for my 74 Scamp that I drag race and I have been having a difficult time with it heating up faster than it did with my 340 and it also takes longer to cool it down. The machine work was done by Kammer's. They hot tanked the block after doing all the machining. But im pretty sure the issue is that the block has been filled with Hard Block which pretty much takes away about a 3rd of the water capacity in the block. I run straight water with coolant additive that is supposed to help keep the water 30 degrees cooler than just plain water. I run a stock style pump but with a Moroso belt drive pump. The belt drive has a underdrive pulley on the motor. I also run a 3 year old Afco 2 core aluminum radiator. I switched electric fans this past winter from a 1700 cfm to a 2600 cfm thinking that would help but I haven't seen much improvement. I do not run a thermostat. The fan and water pump drive are on separate switches but really never run them separate. I leave the line at 160 degrees because that is where it like to run the best.

My real question is, do I need to slow the water down with a restrictor so that the water stays in the radiator longer, or do I need to pump the water fast with a high volume pump so that the hot water gets out of the engine faster?

any advise would be greatly appreciated!

thanks
BP