i found this 400 block for 50 bucks, and i was wondering what was all involved in building a 434 or maybe a 427 out of it, and also my buddy wants to sell me brodix heads and a single plane bowtie intake and a holley 950 carb, but the intake looks very tall, would it fit under the stock hood? what about with a nitrous plate underneath?

 

It'll probably be cheaper to buy a 434 than to build one. Building a 415, 427 or 434 SBC usually means an aftermarket block. Although it could be done with a factory block, the casting isn't that great for a stroker crank.

As for hood clearance, it will depend on the style of air filter used. A drop base filter will probably fit. If not then some sort of cowl hood will be required.

 

I think with a single plane you really need a cowl hood at that point, even with a drop base I don't think you would make it.
Look into a short fill, then grinding the block. Might be doable. And you NEED a small base circle cam, and short rods probably make it easier too.
A 434 is a 427 that has a .030" overbore. So I imagine you'll need to bore out this block to get it fresh again, so you CAN'T make a 427 anymore.

 

so a 434 is a 400 .030 over with a 4in stroke? what company sells good kits to do this? and will it all be ok in a stock 400 block?

 

400 SMALL or 400 (396 s are stronger) BIG block? Big difference...

Factory 400 small blocks cylinder walls are too thin for much.

 

You need to take the block to a machine shop, have it crack tested and have the cylinder wall thickness checked. this way you can see if it is even possible to do what you want and if the block is even any good

 

.030" is the most you can safely overbore the 400 block. If it sonic checks ok, .040 is the most you want to go. As I already mentioned, putting a stroker crank into a factory 400 block isn't advised. There just isn't enough metal around the areas you need to grind for clearance. You'll make an already weak casting even weaker.

Stick to building a 406. If you want something bigger, buy an aftermarket block or go to a BBC. A bigger displacement engine also needs better flowing heads. I wouldn't recommend anything smaller than something like AFR 227 heads on a 434. The air flow requirements of a 434 exceed anything a factory SBC head can provide.

 

I would not do a 434 with a stock block. And If I could redo my motor I would have a 421 ci 4'' stroke in a 9'' deck height just do not make a great combo lots of side load on the pistons short cop height you can onlt fit a 6'' rod. Go with a 3.85 stroke you will be happer in the long run and remeber with a stock block 600-650 hp max thay love to break on #1 main thru the fuel pump boss.

 

ok so i think ill stick to just building a 406, cause the blocks stock bore right now and ill just go .030 over and still be safe, but i still have a few questions
if i plan on about 550 on the motor and possibly a 100 shot, will the 2 bolt mains be ok? im probably planning on an all forged bottom end, so that will be sufficient right? id like around 10;1 compression so i can still run 93 pump gas, and if i have brodix heads with a tall single plane intake with a 1/2 nitrous plate and a 950 holley would i clear a 2" cowl hood? i love the look of the 2" but not so much the 4", could i get away with a 2"? i want this motor to be reliable and last, but i still want gobs of power when ever i need it

 

2 options. Keep the factory caps and have studs installed then have it line honed to make sure everything is straight. Second option is to buy aftermarket 4 bolt splayed caps which will still need line honing plus drilling and tapping for the splayed bolts.

Personally, I think you should just stud the 2 bolt caps. It will be more than strong enough and the web around the mains isn't thick enough to properly support 4 bolt caps, even the splayed ones.

The 2 bolt main 400 blocks are stronger than the 4 bolt ones.

 

I think you will clear the hood with that combo. As for a 2 bolt the block is said to be stronger than the four bolt blocks. You can use splayed caps or studs if you like but if it were me i would just use new gm bolts or ARP main bolt kit. All the failurs I have seen are on number one main and it pulls the blocks apart bolts or studs never break only the block. This was with about 800 hp level.

 

ok so ill just stud the stock 2 bolt caps and have it line honed, with about 10:1 compression, with brodix heads that have been ported, and big single plane bowtie intake thats been cleaned up, and a holley 950 carb, with a very large roller cam, could i possibly hit around 550 hp at the flywheel? if everything beneath the heads is forged, is should be up to the task right? also to turn this motor to 6000 or 6300 shouldn't be a problem right?

also, if i really wanted to, do you think this motor could handle a 100 shot? i wouldn't go any more than 100....

i dont think it would fit under the stock hood, but would i be ok with a 2" cowl? i really hope so cause i think 4" is a little much on 3rd gens