10.1 compression??? 400 sbc 4 bolt main

i am trying to build a pretty strong street and strip motor from a stock 400 thats getting bored out, using my existing stock heads. I am looking for 10.1 compression ratio. i am getting a new rotating assembly and am not sure what size pistons to get or rods.pretty much everything is up in the air, i am starting with the block and heads, could really use the advice.  

400 is a sweet ci large smallblock. Do some research the reason why it is not so popular is because it has/had overheating problem do to thin cylinderwall/waterjacket design I think the 400 was marginly ok on stock bore but will have overheating problems when bored so do some research I can't remember if there is any remedy at all short of a motown block which doesn't have the stock block problems just don't want you to waste a bunch of money and then have these problems but a 10.1 400 could make some nice power with the right heads and cam.

I would also look into getting some aftermarket heads used is a good way to go because even if you port your stockers it's really hard to make any power unless they flow decant and you can't tell that unless there flow tested you can easily lose 100+hp from just heads  

I would advise against boring it out if you plan on using it on the street very much at all.  The cylinder walls are already thin and you with boring it, you will sooner or later run into to heating problems.  

As for the mains, I've had 2 different engine builders tell me face to face and have heard it through a friend from another that 2-bolt main 400s are better starting points for 400s then 4-bolt mains.  I was having an engine built (race only engine) about two years ago and was considering a 406 and the guy I ended up letting build the engine (I went with a 383) said for his own use, he wouldn't fool with a 4-bolt main 400.  But anyways, the reasoning behind their opinions was that with a 400, the outer edge of the mains is already weak, and adding the extra bolts out there further weakens it.  They both said this, and thats why they both suggested if I wanted a 406, to use a 2-bolt main block.

As for heads, you would make a lot more power with aftermarket sets, and may come out with more bang for your buck going that route.  Getting your existing heads worked will probably cost as much or more then buying a good set of aftermarket heads.  
Take a Ride on the Wild Side

Take your crank and build a 4bolt 383 it's fairly easy to make 450hp and 450ftlbs of torque in a light car that's getting pretty scary.

here is a flow chart to show you how big of a role heads can play with the right combination's
http://users.erols.com/srweiss/tablehdc.htm#BBChrysler  

That's what I would do (its actually what I did, lol).  I got a 4-bolt main 350 block and had a 383 made out of it.  Now mines a race only motor.

Mine has a Scat 4340 forged 3.75" crank, Scat 4340 forged 6" H-beam rods, and Mahle 14:1 forged coated allum. pistons.  

Solid roller cam, with about .660" lift and over 300* duration with 1.6 ratio roller rockers (and don't cheap out on rockers, get the Crane "gold" ones).  

Pro Action heads, port matched to 1205 Fel Pro gaskets, 2.08/1.60 valves, 64 cc chambers.  With a Victor JR intake port matched to a 1205 Fel Pro gasket topped off with a Proform 750 cfm carb (don't buy proform rocker arms).  

Never had it dynoed but the guy that built it said he would garuntee 560 hp.  Anyways, IMO, 383s are the best way to go for a pretty stout small block.  Atleast using stock blocks anyways.  
Take a Ride on the Wild Side

I built a 400 .030 over (406) for street and strip. If built properly it will be fine. I would not use stock heads. Buy the best after market heads your budget will allow. Even low end after market heads are better than stock. Maybe even used Chevy Vortec heads. My engine was based on 2 magazine articles. The engine was called The Impersonator and The Impersonator II. I am currently getting about 450 hp and with some professional tuning I should get around 480 with equal or more torque. You can check out the specs of my build at hotrod.com , readers rides. Good luck.  

There is two different older vortec heads I forget the numbers one is prone too cracking pretty easily the other is good you should be able to findem unsed for 0-250 you would have to have them machined for a highlift cam anything over 420" lift but they will be good for up to 500 or so hp! but if you have 1000 then you could always get a set of trickflows at that price. I think they were also aluminum watch the chambers though they are small 58cc not sure if they had the larger chambers like the new ones  

I run a 415 stroker every day and have never had a overheating problem . I started with a 2 bolt 400 block that i changed to a 4 bolt with howards splayed caps next i bored the block 30 thou then installed a eagle 3.85 stroke crank with 5.7" h beam rods topped with wiesco forged piston to produce 10.7 to 1 comp. On the top i run edelbrock e tec 200 cc alum heads if in budget good head for the money approx 1,200 pair for the valve train i run a reed hyd roller 234-242 at 50 with 538-548 lift for rockers i prefer comp steel rollers for everyday use.For my fuel system is edel pro flo injection all these parts together produce a nice little chunk of power and my cooling system consists of a large alum rad (biggest)i could squeeze in with stock water pump,stock serpentine system and stock shrouds also stock clutch fan assy. it has a 180 therm and runs 181-185 wheater it's 75 or 95 in thru town driving or on the hiway. Forgot to mention e-tec 200 heads have 64 cc chambers with 202-160 valves good street size for low end torque

Best of luck with your build  

Ya 383's can make some power I wouldn't doubt those #'s with your good setup, 383's (can) turn the r's. Plus they (can) sound real nasty

Ya throw a blower on there and you'd be at 700 easy superchiller another 100hp.
Or throw some nos on there. It's probably already scary though  

A 383 is a nice engine thats for sure.But there's nothing wrong with a 406.I am currantly running a 406 in my 69 Z28 on the street dayly.It runs between 185-195 all day.I would take others advice and go with the best aftermarket heads you can afford.I have Dart Iron Eagles on mine with flat tops 10.0 to 1.406's are real torque monsters.  

the stock 400 heads suck is what I've heard there swirl port but whoever could be wrong?  

the stock 400 heads were not swirl ports they didn't make swirl ports until 1987.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

The stock 400 heads suck because of poor design.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

so here is where i am at, I bought a pair of world products sportsman II heads, 64 cc. Edelbrock RPM air gap intake, edelbrock 750 carb. Internals is stock crank and rods, new speed pro pistons, lunati voodoo cam with advertised duration- 276 int./ 284 exh., duration @ .050 is 233 int./ 241 exh. with a .504 lift on int. and a .525 on exh.
pete jackson gear drive timing set, aluminum 1.5 roller rockers, new harmonic ballancer, edelbrock 110 fuel pump,and have not yet figured out what pushrods to use! people keep telling me i can use stock length and other people tell me i have to measure them. so can i use stock length??  

it should run real good with that set up if it doesn't overheat the 200cc II's flow real well unported out of the box. The gear drive will mostlikely be real loud maybe not? worst case scenario use the crank etc. and build a 480hp and ftlb. 383
If you endup going that route in the long run start with a newer rollertrain block.