Hey everyone, i'm thinking about swapping my 305 sbc out and putting a 400 sbc in, can anyone tell me if everything will line up, or any problems that I will run into, and if it's even worth it. thanks ahead of time

 

http://www.carcraft.com/techarticles...ine/index.html

 

Thanks for that, but i'm more interested in this 400, I could get one for 700$ and I just want to have this engine so I could rebuild it so I could have some real power, but that article was pretty cool, thanks anyway

 

A small block is a small block. You need heads with steam holes drilled in them, but other wise it should be a bolt up affair. Just make sure you have everything needed to feed 400 cu inches of engine or there's no point in swapping.

 

remember 400s are externally balanced, so you will need a flywheel/flexplate and a harmonic balancer thats specifically for a 400. someone also mentioned the steam hole issue if you use heads from anything other than a 400.

otherwise, fits just like any other small block.

 

no worries! ima sure you're gonna build one hell of a powerplant outa that 400 anyway.. i am just passionate about the lsx style motors. they are a dime a dozen and perform well! gotta love it!!!

 

So you mean Carburetor wise?, will the 4bbl rochester quadrajet work?

 

Can someone tell me what I will need to get 400 hp out of ths 400 sbc and keep it cool, because everywhere I look everything says they always overheat because of steam holes or something, and you have to get some drilled at a machine shop or something

 

the overheating issue was due to a lot of guys swapping heads onto their 400 block without drilling the steam holes first. Since the 400s do not have the same water jacket setup that other sbc engines do, steam holes were added to help keep things cool. Easiest way to see where to drill is by looking at a set of 400 head gaskets vs a set from a regular 350. There should be instructions somewhere on the site here, I'll try to see if I can dig anything up.

 

Alright thanks, that would be a lot of help, now what about my 400 hp goal, what's the easiest way to make it have that much horse?

 

I'm going to be doing this same swap shortly. Anythings gotta be better (other than the great mileage) of the 305.

I'm fairly new to the motor portion of the car build. I'm a drywaller by trade, so I prefer the body route. But from what I've read, and I'm likely to be corrected, but tossing a better set of heads 200 w/ 64cc and a nice flowing intake could add roughly an extra 50hp to the 250 stock hp that these motors averaged. So that puts 'em around 300hp with not much else done.

Cams and stuff, maybe I'll understand in a few months. My mechanic friend has a "solid" cam for me that came outta a 400 car that ran low 11's. *shrug* It's goin' in. I'm certainly not certain what it would increase output wise. So lets say 15hp.

Thats roughly 315, Headers and exhaust could add another 10% or so, bringing us near 350hp. Or so I think, eh?

So what do we do to get our last 50 horses? I'm sure by I'm done my next pint this'll be solved and corrected.

No rush though, mines a winter build. Lots of winter where I am. :S

 

Thanks for the responce, it really helped

 

You need better heads to make 400 hp out of a 400 small block. The stock truck & passenger car 1.94 valve heads just don't flow enough air to make more than about 340 hp no matter how much cam you put into it. Believe me I've tried.

My car put down 286 hp to the rear wheels with the port matched 1.94 valve heads and jumped 42 hp to the wheels with just a head change to a set of box stock Sportsman II iron heads. That put it right at 400 hp at the crank. Much more is possible with these heads but it would take a bigger cam and higher compression than a street car daily driver would tolerate.

 

Oh yea, A 400 really needs better longer connecting rods to make 400 hp too. The stock short rods are a hindrance to making HP and with the stock cast crank you really shouldn't rev it past about 5500 rpm so that hurts HP generation as well.

A nice forged crank & H-beam rods and a set of splayed main caps will allow you to rev the snot out of it and build some great power too.

A friend of mine had a 67 Camaro with a 400 small block and was running 400 hp of nitrous thru it to get 154 mph trap speeds in the 8.90 ET range.

 

For your HP goals you will need to replace pretty much everything but the bare block and crank so paying $700 for that and still needing to rebuild it is too much.

If you lower the HP goal to about 340 you can keep pretty much every major part except the intake but $700 is still too much. I can get one with a 30 day warranty for $150 at the junk yard guaranteed to be rebuildable.

Unless it has a nice intake & carb and is in good running order don't pay more than $200 for it.

 

So should I even buy the engine?

 

Depends on your budget and how inexpensive you can get the 400 for.

Unless it is in great shape, recently rebuilt and has good parts on it that you can re-use in your build it is not worth $700 when your goal is to make 400 hp.

A high mileage 400 may not even be rebuildable as they can not be bored more than +.040" over without overheating problems on the street.

It's hard to find pistons for one above +.030".

A 350 short block is definitely cheaper to build and can be found with a stronger 4-bolt block and a forged crank plus it all ready has the longer rods.

The 400 4-bolt block is actually weaker than the 2-bolt version because there is less material in the main web area. That is the reason Chevy quit making them in 71 and went to all 2-bolt blocks.

 

yeah i agree i would buy a 4 bolt 350 an start there. better cheaper more efficent less head ache. i mean i bought my chevy 350 4 bolt for 100 bucks in good shape. soo your choice but might be smarter for u to go the 350 route

 

yeah I was thinking the same thing, well, then is it hard to make 400 horse out of a 350?

 

na it anit that hard really i mean depending on the budget, but u could make good power out a 350 for cheap

 

Ok, well I don't really know anything about the internal engine parts, and buying them to make them work well with eachother, if anyone could explain a little on like, lift and duration because I have no idea what that means. and i'm just curious, how fast would my camaro be with 400 horse in the 1/4 mile. thanks

 

well for on fast your will be with 400 hp all depends on the rest of the car like your trans and gears and traction. the weaker the transmission the less power u will put to the ground and with lower gear the slower acceleration. but never the less your car will be pretty quick with 400 hp for sure but the more hp u get the more u got to upgrade the rest of your running gear. i mean 400 hp with probably break something on a semi old 700r4. but here a link to explain how the cam works as well better than i could lol
http://www.auto-ware.com/combust_bytes/camspecs.html

 

wow, thanks a lot, thats explains a lot

 

yeah but it could be a good idea to do some upgrades to the car as far as gears and exhaust and trans then go ahead and put a built motor b/c anyway u look at it u will have to do the upgrades either way so

 

Yeah I want to do all those upgrades, But I don't have money at the moment, I just want to get an idea of what I can do with 400 horse, I want to rebuild the whole car sometime in the near future, but I also have to save money for other stuff. But if you could give me an idea of what kind of gears and transmission work I would need to keep 400 horse and not break anything that would be cool

 

I understand money always tight for car parts always on a budget lol well gears part would probably like u could go 3:73 would be best for street strip use i think but if your not the weekend warrior maybe 3:55 ratio would also be good. but the gears really dont breaks so u dont have to worry about failure with them but trans is a weak point for high horse power but a shift kit would help but it dont matter eventually u will wear a stock trans out with that much horse power. thats when it time to take it to get it rebuilt. just the stock clutches and bands wear out not made to handle that much power. if u no someone who will build it for u that no's what there doin it could cost like 800 bucks so not that cheap to beef it up but could be done a little cheaper

 

Thanks again, I know someone who can rebuild transmissions, so I can just buy a kit or something?, so say if my transmission had a shift kit, I had 3.55 axle/gears, and 400 horse what do you think I would run in the 1/4?

 

well still depends on lots of things but u could probably cut somewhere in the ball park of mid 12's but all depending on traction and what not

 

yeah and if your tranny guy no's his stuff he no's what to get thats cheap but wont salvage performance. i got my trans done for 800. i got most parts from a company called transtar that my transmission guy had a acount with so good luck with your camaro and your upgrades

 

Thanks a lot, and thanks for all the info

 

no problem good luck

 

Low 13's unless you do something with the stock rear suspension and get some good tires. Mid to high 12's with traction.

 

If you really do build 400 hp you will break the sun shell on the 700R4 and a few other internal parts not just the typical worn clutches. You are better off having a reputable shop upgrade and rebuild the trans right from the start. It will run you at least $1000. Look into Rossler as a parts and cost comparison.

 

Where are these $200 400cid sbc coming from? And I found this to be a good intro to the subject with some interesting ideas:
http://www.amazon.com/Hot-Horsepower...3640202&sr=8-6

But even in Car Craft most sbc builds for around 350-400 hp run in the 2-3K range when all is added up. That is heads, crank, intake, carb, and cooling system.

 

$200 is the most I would pay for a 400 sbc core. It still needs fully machined and rebuilt on top of that.

 

Comp Cams 292H cam, Sportsman II 200cc iron heads, Victor Jr. intake, 750 Holley carb with some forged flat top pistons and you will be right at 400 hp in a 350. It will sound evil with one heck of a lope for a street car.

It will need 2400 stall and 3.42 gears minimum. 3000 stall and 3.73's will do much better. 4000 stall and 4.11's are brutal on the street but oh so fun.

1-5/8" tube headers and 2-1/2" dual exhaust minimum.

I ran this in a 69 Nova street / strip car. Lots of fun to try to control on the street. Car ran 12.30's on 26x9 slicks at LACR's 2300 foot elevation so that is a 12-flat high 11 second car at sea level.

1-3/4" tube headers and dual 3" exhaust will gain some power but not enough to make it worth the cost of the parts in my opinion. Use the money to make the car lighter with a fiberglass hood, aluminum driveshaft, lighter brakes, etc...

With 12 to 1 compression, race gas and a bigger solid lifter cam the same 350 ran 11.05's on the same 26x9 slicks with the 4.11's, 4000 stall and a powerglide with transbrake & open headers. It even did it on the 8.2" 10-bolt.

 

Would I be able to run pump gas on this motor?, only reason I ask is because you said race fuel

 

With flat tops it will run on pump gas. I ran premium most of the time but it will run on 87 if you have to. You will have to back the timing down a little on 87. It really liked 100 low lead av gas.

I ran it for five years in the basic configuration while I was in college and too broke to make any changes to the car running it on pump gas as a daily driver that I took to the strip during the summer.

I had the car for nine years and it evolved and became more and more of a race car eventually being a strip only open header race gas trailered toy with 5.13 gears and a spool.

 

Damn that sounds like one badass nova, what's the fastest time you've gotten it?

 

It ran consistent 11.05's with the front wheels in the air past the 60-ft timers. This was at our 2300 ft elevation so it was a high ten second car at sea level. All motor.

I sold it seven years ago after I lost my job and have been wanting to build another one ever since.

I am slowly building my 68 Camaro in the same manner just with a big block instead.

 

Damn that sounds like one badass nova, what's the fastest time you've gotten it?