Block filler.
 

Just reading up on 4.06 and 4.08 bores, for future reference. Looks like with over one bar block filler is reccommended. So what's the deal with this stuff? Can you pour it in on an engine stand and spin it aroud, do it yourself? Or how does it work? Does it make the engine run hotter?

Uh, what's block filler?

It's basically like cement. You pour it into the water jackets and it strengthens the bottom end of the block. Due to this it is not recommended for street cars. It is mostly used in drag cars that don't run long.

Adam, have you had the cylinder wall thickness checked? Why are you going to bore the block over that much? If it is just because you want to build the block you already have now I would just pick up another 350. You can pick them up for around $150. If you just want the extra cubes from a bigger bore, it's not worth it. I prefer the thicker walls for strength over the extra cubes.

I've got the heads on. I'm going to run it as is and see how it does. I was just thinking... if it doesn't run ok, or in the future.

I'd want to bore it over to get rid of the damage. If 4.04 didn't do it, I'd have to go 4.06, or 4.08. Which is when I'd want block filler.

I'd order lower compression pistons 2618 forged, and smaller HGs with the correct quench. Also a blower cam. Mmm. :D I think regardless of how it runs I'll treat myself once I get a job.

...Think I'd get some studs and girdles too. Do it right. So then, will the block filler make it run hotter???

Just save up and get a Dart block instead. Then you won't have to worry.

Wait... I just read something about this. Is block filler supposed to fill the whole block? Or just coat the insides??? I was thinking it was just moved around to give a coating and then poured out...

Is your BB a GM block?

You pour it in about half way up in the water jacket and leave it. That's why it doesn't work in a street car.

Yes, it is a factory 2 bolt GM block out of Phil's old '85 Suburban that he bought from our mom's cousin. The stock crank broke with about 200,000 miles on it. All it needed was a light hone and a line bore. I bought an Eagle cast crank and I'm using the original rods with ARP bolts.

Here's the instructions for Hard Block.

http://static.summitracing.com/globa...str-022005.pdf

OIC, thought it was just a coating.