Technical New SBC 350. Also new geyser. Getting hot while trying to break in

This is why you do new start ups with straight water, I learned the messy way a long time ago. Water is much easier to clean up! My Olds had a air bubble somewhere, geysered 3 or 4 times. I ran it through the 20 minute burn in with a buddy topping off the radiator every time she blew. He commented that if it can take a break in like that it'll last forever. Same engine in the car 20 years later, still runs like a clock...a loud, fast, gas consuming clock.

 

I believe I installed correctly mainly because they say this side up right on them. That being said the holes are symmetrical front and back when you flip em apart from the center plugable one.

 

yes. All accessories direct bolt on including the belt which looked pretty new.

 

Do you know what type of rings it has on it? Old style cast iron rings make a ton of heat on break in due to rough hone. They will make the exhaust glow. Moly rings not so much.

 

Rings are Moly

 

I will agree it may just be a case of the radiator just being too small to keep up with 2500 rpm while stationary, with no road speed forcing air through the radiator and you may just need to rig up a temporary large radiator just for the break-in.
The original may be fine after you get it through the break-in, out on the road and driving.

Makes having a engine run-in stand a nice option. Nice thing is your Bucket is the next closest thing to a open run stand, shouldn't be hard to rig up a bigger temporary radiator.

 

A squirrel-cage blower (from a furnaces) or a large 24"-30" industrial fan placed in front of the radiator or doing maintenance reply helps to keep the temp in check .
Slow down when filling the cooling system helps prevent air locks.
Fill the system with the thermostat housing off , then install & top it off .
If the headers are red , the fuel charge is firing late , increase the timing .

 

thanks for the comments. Triggered my memory that I have a portable blower that should push some volume.

 

Cooling on my run stand, 90* outside temp, 468 ci Pontiac run at 2000 rpm for 20 minutes, temp stayed under 190. I had one fan off to the side blowing the heat away from the headers, fans blow away from the engine pulling air through the radiator ( 18" x 24" core ). These are school bus A/C condenser fans, you can hear the engine slow down when they come on!

 

Thanks for all the help everyone. Just an update. Mainly settled on just that the radiator was not up to snuff to handle the 350 from the tired 283. I had replaced the thermostat, lower hose, water pump and made sure all was burped well and had like 3 fans going still no impact with the original radiator. Picked up a knockoff aluminum replacement and ran all good. 190 degrees during break-in.

Plan to get it through break in, and work to see if I can get the original up to par (build a shroud, upgrade fan) and see if that works after motor is settled in. If no, take a look at the more modern reproductions e.g. Brassworks

 

One trick I learned from an old timer to not make such a mess was cut the bottom off a 2 liter plastic bottle and stick in the radiator fill. It gives the water/coolant a little more room to burp instead of all over the floor. You seem to be past all that, so for future reference.