400 block question?
 

I baught a 400 engine casting number 3951509 that is punched .060 over is this safe for a dirt modified? Let me know what you think.

One way to know is to have it sonic tested.

what is sonic tested and where can it be done at

509 BLOCK I THINK IS THE WEAKEST OF THE FACTORY 400 BLOCKS.
BECAUSE OF THE 4 BOLT BEARING CAPS.

Sonic Testing
 

Here is a brief article explaining what Sonic Testing is.

http://racingarticles.com/article_racing-73.html

X2!!!!!!!!!!!! and at the bore on a 400 block there is a good chance of cracking from the head bolt hole to the cylinder.

Look it over close

not all 509s are 4 bolt

i heard that that some shops drill the steam holes, thread them and plug them,to prevent cracking in this area, for drag race use. any experiences with this? i believe that a 509 block is one of the stronger 400 blocks. i have one in my garage now that is a two bolt block that has been studded,line bored, and filled to the bottom of the frost plugs.

400
 

To see what is required to add life to the head deck of a 400, you may want to check out the old Bill Jenkins smallblock chevy engine building book.

It details how to drill, tap, and plug the steam holes. It also shows to add plugs with holes in them to the big water holes in the deck and mods to other water holes.

I followed this once and the 400 block lived 7 full seasons of drag racing. It eventually cracked from a head bolt hole to the bore. Rest in Peace.

mark, were you using studs,or bolts in the decks of that block?

Just as Mark says, i have a 400 on my engine stand 4 bolt 406", and i drilled and tapped the steam holes, and the big water holes. I also have a 400- 2 bolt in my Malibu. 377" and it's been in the car since 2004, more than 200 passes on it and never been tore down. It has 13.5 pistons and on alcohol. I use studs on both the mains and the heads. In fact i use studs (mains and heads) on every engine that i have, even the Dart little M blk 434" that's going in my car in the next few weeks.
I've seen too many helicoils in blks in my life to not use them, i also use Copper or MLS head gaskets only.

Zip.

400
 

I had bolts, which I know put more stress in that area. Studs might have helped in this case.