[WakBordr7387]

I found this old thread while doing a search.
400 small block re"performance"build

I figured Id make a new thread rather than resurrect an old one.
Im also got a 400 bored .060 over in the planning stages right now, This is gonna be a pretty strong street motor and probably be used at a dragstrip just for the heck of it.
So far my plans are aftermarket crank and rods, forged pistons and Im seriously thinking about putting a shot of nitrous on it or maybe even a small blower.
But my concern is, Ive been hearing a lot about how 400s overheat easily, especially when bored out. Ive also been told that ones that are bored .060 over aren't real strong because of the siamesed bores. In this thread I found they were talking about block fill. Do you think this would be a good idea on an engine like this to add strength but also not let it overheat?
This will be driven on the street mostly and I definitly don't need it overheating which is why Im asking.
Thanks guys


Brad

[BOBCRMAN@aol.com]

If you only "short fill" the block, heat problems will not be a big factor. Fill the block to the freeze plugs. Lots of these running around on the street.

[WakBordr7387]

Thanks bob, I just wanted to make sure on this.
Appreciate it


Brad

[Rob Keller]

Excuse my ignorance but ...

What is meant by "short filling a block?"



Rob

[WakBordr7387]

This is block fill


It basiclly just fills in the water jackets to add strength to the block.


Brad

[Arcuden]

Short Filling refers to filling the block only partially, as opposed to all the way. Like Bob said, up to the freeze plugs.

Supposedly, since the majority of the heat is generated in the top inch or so of the bore where combustion occurrs, filling the block this way doesn't have a significant impact on water temperature, while also stiffening and strengthening the bores.

[WakBordr7387]

Yeah I think I will be putting some block fill in this block just to make sure its good and strong. Any other precautions I should be aware of? Should I let a machine shop fill it or can I do it just by reading the instructions?


Brad

[camaroman7d]

Brad,
Before you run out and fill (short or tall) you need to know a few things. First if the block is already machined, I wouldn't fill it. The block fill will distort the cylinders as it dries and should be done before machine work. The other thing is, you can expect higher oil temps, since there will be no water in the lower half of the block to carry away heat, it will make your oil quite a bit hotter. You can cure this by running an oil cooler.

Royce

[WakBordr7387]

Thanks Royce, The block has been machined already. Ive been meaning to take it to a machine shop to make sure its all good. But Im guessing since its already .060 over, I wouldn't be able to have the cylinders straightened up after the block fill.
Oh yeah I was definitly planning on an oil cooler, with or without block fill.
Thanks


Brad