Not too far down the road i will be jumping the fence to a big block and the 400 will be my choice. what do i look for when buying a 400 block? what years are best? how far can they be bored, is .060" safe? Big blocks are a whole new world for me so i'll need some coaching. thanks

Be side the 71 230 thick main web block. They are all the same..need to them sonic tested..wall thickness..

You can bore it .60 over but the most common bore on a 400 block is 4.375 bore which is .35 over. There is alot of off the shelf piston choices for that bore size If you go .60 over you will most likey need custom pistons.

Those questions are why I wrote a whole book on big blocks.

Where is this Book and is there anything in it. I don't know ??

Andy, what is the name of your book? i'll see if i can find it at the book store tomorrow.
ok, now what are the pro's and con's of the 4.150 crank and the 4.250 stroke for the 400 block? mostly street use, but i'm looking to make some power and will hit the track a few times each season. i'd like to make 700hp on pump gas to start and building it up over the years to race fuel only as i'm now doing with my small block(408).
i will be using an indy head with the combo.

thanks Bob. i'll look for it tomorrow.

Great book thanks AndyF

I prefer the 4.25 or 4.3 stroke with BB Chevy rod sizes in any of the BB, 400 or 440 700 HP is not hard with the right heads, intake and camshafts and rocker gear. As already said have any block sonic tested before buying it, you want .150 minimum on the major thrust sides after boring for a compression motor above 8.5 to 1 N/A

The 4.375" bore size is the most common, mainly because there is a large and affordable selection of piston rings in that bore size. basically most of the 400 blocks are all the same (except the '71 which has more material in the main webbing area.)
For stroker engines, the cut down 440 3.75" stroke crank with 440 rods is still fairly common. Don't use the stock 400 rod length as there is not much piston selection for that combination. Most of the other stroker combinations are going to use the 0.990" piston pin size, so it it easiest to just get the entire striker "kit" of crank/rods/pistons all at one time.
The welded up 440 crank 3.9" stroker is not very popular any longer now that there are many affordable aftermarket stroker cranks. A friend still has one, but his custom pistons were very expensive.
I just built a 500 cid (4.15" stroke) 400 with a 440 source kit, and it is an easy install. The only item needing to clearance was a very small amount off the oil pickup boss. Kit clears internal oil pickup.
I have not built a 400 with crank strokes larger than the 4.15", so I'm not sure how much clearance they need or if they require an external oil pickup?
If you plan to build over 700 HP, you may be better off using one of the aftermarket blocks

4.125 vs 4.25 stroke. The 4.125 usually uses a RB rod at 6.76" which gives a very short and light piston. Compression height around 1.13" with an oil support rail required. It revs fast, has decent rod ratio and the short piston is prone to rock which may shorten its life.

The 4.25 ususally uses a Chevy rod at 6.535" with a taller piston. More cubes and a more stable piston with a tradeoff in rod ratio.

Some good info posted already. For your 700+hp target, this is worth repeating.
" As already said have any block sonic tested"
This is the same for any passenger car, production, block (440, 400, 360, 340, etc).

For your power target, the heads and porting will make the biggest difference. Spend money there and you will not be disappointed.

There are lots of good stroker combinations. I prefer any that uses a 2.200" rod journal, and 0.990" piston pin. 4.375" is the bore size to use. The rod bearing choices with the BB Chevy journal dimension are very good. You can think about align boring the block with aluminum caps for the 440 main bearing size also. Again better bearing selection compared to the 383/400 main bearings.

I really like the 4.250" stroke in the low deck. It fits in the block better than the 4.150" with Mopar rod journals. With a 6.535" steel rod it uses a piston around 1.32" compression height (depending on exact block deck height). Have the crank counterweights no more than 7.25" dia to clear things (like the piston pin boss), my crank was turned down to 7.14" dia, mostly for balance reasons. As I recall, my Callies crank counterweights were "cam cut" to 7.32" and that cleared as a shelf part.

Although there are lots of off the shelf parts, don't be afraid of the cost of a couple custom or modified parts if you decide you want a particular feature (like a 6.700", or 6.635" rod for street use). Custom compression height, flat top, pistons can be bought for just a little more than the same brand piston with off the shelf features. Same for crank journal sizes or counter weight diameter. A few hundred bucks isn't a lot more when you are building 700+ hp. A nice Callies crank ground to your specs is an idea..., but other less expensive cranks will get the job done at that power level.

The attached tables may be out of date, but give you some ideas. The top one is the low deck (9.980") and the bottom one is the raised deck (10.720"). You can adjust deck height as desired. For pump gas compression ratio, you will need to calculate head chamber size and piston to deck, etc. you might need a dish piston with around 14-18 cc dish.

thanks guys, alot of info here. i'm going to look for andy's book this morning.
one other thing, i was looking at the $599 cranks on 440source are they any good for 700hp+ combos?

400 Block

K1 4.15 crank w/ BBC pin
6.48 K1 rod
1.425 CH piston

1.56 rod ratio

I noticed the KB pistons for that compression ht appear to be lighter than the 1.32 CH pieces.

I found andy's book today. i'll give it a read over the next week. i'm going to see if i can find a 400 block local here for now. i have to get back to my small block project for this year.