Thermostat High vs Standard flow

[ranger danger]

I just finished replacing my OEM manifold with an Edelbrock Performer on a 454. I put the first one on (bought used for $100) and when I refilled with coolant I found a 3/4" crack in the casting running from one of the 1/2" water ports. I went to my local parts store and got a brand new one and installed it. Before the change, I had a 180* high flow thermostat in it (the one on the right in the pic) which kept my temps at about 185*. When I replaced the manifold I went ahead and replaced the thermostat at the same time with the one on the left in the pic, also a 180* (standard flow). Now my engine temp is up to 195*-200*. I'm pulling the new one out and putting the old high flow back in. I'm surprised that the high flow made such a big difference in operating temps.

[ranger danger]

Now for part 2
I used Fel-Pro Printoseal gaskets when installing the intake manifold. They came with 4 little square pieces of metal about 1 1/2" square with about a 3/4" hole in the middle. The instructions called for putting these in the exhaust crossover holes in the gaskets. The old gaskets did not have them installed so I called the parts store to question this. The answer I got was that those pieces are for smog requirements and because my engine is not smog controlled, I did not need them. I left them out. Was this the right decision?

[ranger danger]

Update:
I changed back to the high flow thermostat (on the right in the pic) and shes holding steady at 185*!!

Whodathunkit!!

[Captainfab]

Did you purchase the high flow thermostat at your local auto parts store? Do you have a brand and part number?

[ranger danger]

The high flow I got from Napa Auto Parts. Its a Belkamp part # BK 8251007. $12
The next one I get will be a EMP/Stewart part # 301. $30 from Summit.

[68gmsee]

When in doubt on the operating temp of a thermostat, I place them in a pot of water on the stove and with a know good thermometer, monitor the water temperature. I have found some that won't open until well above the indicated temperature rating.

[AcampoDave]

As for your crossover restrictors...living in Vacaville, you could have put them in since your climate is rather warm. However, you still should be fine. The crossover just helps warm up the motor in cold weather especially with cast iron intakes, which warm up more slowly than aluminum.

[ranger danger]

Originally Posted by AcampoDave

As for your crossover restrictors...living in Vacaville, you could have put them in since your climate is rather warm. However, you still should be fine. The crossover just helps warm up the motor in cold weather especially with cast iron intakes, which warm up more slowly than aluminum.

Thanks Dave. This burb spends a lot of time in the high Sierras. The family has a small ranch around Pollock pines and we spend a lot of time there. We also go to Lake Tahoe a lot. I guess this will help it warm up a little faster on those cold snowy days!

[Texas1963]

As a precaution, I always drill a couple 1/4 holes in the Thermo so if it does fail, you will still have some flow.

[ranger danger]

Originally Posted by Texas1963

As a precaution, I always drill a couple 1/4 holes in the Thermo so if it does fail, you will still have some flow.

This thermostat comes with 3 - 1/8" holes already drilled in it.