400 sbc, good?

[TC]

Also all you guys that are saying these motors don't make power are Crazy, I have a few friends running 400's and they spin them 8000rpm..........

Hell my 406 will make over 600hp and peak hp should come in around 6700rpm......

[Loren]

The problem is more than just a narrow area between cylinders, it's that the siamese portion of the cylinder walls is getting zero coolant, just heat from the other cylinder next door. Don't you think it's a good idea to have coolant running along the other side of all cylinder suraces? I kinda do.

Siamese bores do work...the Hemi in the avatar has 'em and has never had a problem...but I wouldn't use such a block in something I needed to be street-durable when there is the conventional alternative available.

[TC]

The problem is more than just a narrow area between cylinders, it's that the siamese portion of the cylinder walls is getting zero coolant, just heat from the other cylinder next door. Don't you think it's a good idea to have coolant running along the other side of all cylinder suraces? I kinda do.

Siamese bores do work...the Hemi in the avatar has 'em and has never had a problem...but I wouldn't use such a block in something I needed to be street-durable when there is the conventional alternative available.

I understand what your saying about the coolant, I'm just saying people have been using 400 blocks for years with no problems, hell GM even put them in Trucks...........I always looked at a block with Siamesed cylinders as being stronger since all the cylinders are connected........

[yellomalibu]

I wouldn't worry about the casting number. If the block is in good condition, get it. If the bottom end is built wisely, you shouldn't have any problems with it at your 450hp goal.

If it is already bored .030 oversized and needs to be bored again to clean it up - that's when you need to get finicky. I wouldn't pay much more than scrap price for such a block.
Regardless, have the machine shop sonic check the cylinder walls to be sure they are thick enough to build a motor safely. <-- I don't know what the magic number is for cylinder wall thickness, but the machine shop should. Perhaps some people here can offer their advice in case your machine shop is more interested in making money than being honorable.

Don't be afraid of a 400 or 406 - I would put one in every "toy" I ever own.

[TC]

I wouldn't worry about the casting number. If the block is in good condition, get it. If the bottom end is built wisely, you shouldn't have any problems with it at your 450hp goal.

If it is already bored .030 oversized and needs to be bored again to clean it up - that's when you need to get finicky. I wouldn't pay much more than scrap price for such a block.
Regardless, have the machine shop sonic check the cylinder walls to be sure they are thick enough to build a motor safely. <-- I don't know what the magic number is for cylinder wall thickness, but the machine shop should. Perhaps some people here can offer their advice in case your machine shop is more interested in making money than being honorable.

Don't be afraid of a 400 or 406 - I would put one in every "toy" I ever own.

.030 is all I would go on a stock 400 block, you can go as much as .060 but you better have a good cooling system, because the wall thickness gets pretty thin at that point......Also most shops will sonic test the block to make sure a .060 over bore is possible........

[SpiderGearsMan]

pop for a new dart shp block ................1,320 bucks does not sound too bad

[yannick]

pop for a new dart shp block ................1,320 bucks does not sound too bad

Worth it, considering how much you can put in a stock block...
Stock 2 bolts are fine though. I found they last quite a bit longer if you stud the mains, run a steel crank and long rods 5.7+ when you get in the 500-600 hp range, anything more invest in a race block!!

[JeffMcKC]

I have one ran the Hell out of it. Money needed for ( If you going to run it hard mine was over 700 HP)

Sonic checking the cylinder walls first
Squaring the block
Line up the lifter bore and Brass lined ( Huge issue on the blocks )
Head bolts got to go and studs used the 400 Blocks wont hold good Torque.
Line Bore with a 2 bolt block adding Splayed Caps and straping the front one
receaver groove the block to hold the gaskets
the Block alone will give over 50 HP up in the cylinder walls not sealing to the rings dont go more than a 420 and over a 5.85 rod

If it was me I would get a SHP and build from that they are not ready out of the box to build