Im running two 454 with blowers about 600hp. I recently changed out one of the blocks. Here's the problem I'm using crossover kits and run 120-130 temp. Since I switched blocks its running 100 and below that when I'm going over 2rpms. All I did was change the block out due to a spun bearing. The cooling system stayed exactly the same...so why is the new block running so much cooler? Any ideas?
Thanks

Cleaner passages??? Better water flow?

3pointstar

It's just odd to me that since day one with everything new it ran 120-130 and now with just s new block it runs so much cooler

Or maybe a sender issue since most gauges/senders don't register under 100 ?

Or, there was a restrictor under the t stat housing that was not reinstalled ?

No restricters and the stat goes to 100-105 and then when I speed up the needle goes all the way back down as far as it can go. When I idle again it slowly climbs up to 100 again. Sender and stat are also good because I switched motors and tried them

Having the same problem tried everything I could think of for the last month. I am using a harden marine crossover with bypass, stainless marine dry.
I have cold water going in the block on one side of the crossover and hot water leaving the block and out the bypass on the othe side of crossover.