I've heard that a half fill of block fill in a street 406 will not cause it to have overheating problems, due to most cooling occuring about an inch under the top of the block.

has anyone used a half fill on the street had any problems. Im shooting for around 425-475 horsepower and then up to a 150 shot of nitrous, so do I even need it?

I have a pretty good cooling system I think.

Thanks

Its not needed at that power level. You could still do it since there are some benefits to it but plan on running an oil cooler. Coolant temp will be fine with a short filled block but the oil temp will get out of hand if you don't run an external oil cooler.

Mine is half filled. Runs 180* in humid 90* weather, 190* at idle. I'm running 215cc heads with a solid roller. Not really needed, but I already had the cement.

Thanks for the replies guys, I thought about using it just because of the use of nitrous, thats it, maybe I dont even need it?

What block are you using? IMO I will fill any stock 400 block I build from now on. Much better reliability in my experience. I agree run an oil cooler and you will have issues at all street or strip.

no issues on coolant temp. oil temp is OK at strip. I recommend an oil cooler for street use.

What block are you using? Im using a stock 2 bolt 400 block (509), I will be using main studs for sure i know.