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400 sbc build

8K views 64 replies 17 participants last post by  dragginwagon406 
#1 · (Edited)
Any recommendations on what makes a good build point for a 400 sbc?

Tore mine apart yesterday. Would like to go with different heads (currently 993 heads). Compression seemed pretty high?

More looking for what makes a good cam for these motors for low end too, this is a trail truck. Good target for compression?

Besides replacing the consumables, the intended list is carb, fuel pump, crank, heads, maybe cam, maybe others depending on what I can come across and what makes sense.
 
#2 ·
Trying to gather more info. I really want reliability, and torque and power at lower rpm. This truck doesn't need to see anything over 5000 rpm.

Most things I see are for high hp applications and higher budget/builds for going fast.

Anything you guys can enlighten me on would help me out a lot.

Block should hopefully go in to the shop for initial stuff next week... hot tank, and checked for deck, bores, cracks, etc.
 
#3 ·
The simple fact is those heads are junk. You can port them out but at the end of the day it is a waste of time.
You can toss on some vortec heads, a rv cam, a torqued intake, and make torque around 400 lbs around 3800rpm if you are dead set on keeping the sb400.
Or you could save yourself some cash and buy a used BUILT 383 or 454 with low mileage. The things are everywhere if you look hard enough and a good one can be found for less then 3k. Depending on how much of the work you do yourself you may be able to stay under 2k. But for 3k you can have a running motor completely built that will make close to(383) or more torque(454) then a "built" 400 will for less money. These are general terms. If you like the 400 and don't mind spending the extra cash build it.


This guy has had this truck for sale for a while. I was tempted to buy it for the 468/465 alone before I stumbled onto a 472.

http://www.greatlakes4x4.com/showthread.php?t=244040&highlight=468+truck
 
#4 ·
I have a buddy that wants to sell me his 600+ hp 383 for 3k, but I want to see what I price out since I'd still need some things for the 383 that I would need for the 400 anyways.

I was looking at either double hump or vortec, just trying to figure out good options.

I do like the 400, it's a little uncommon so I do like having it. I've been wanting to learn to build a motor, so that has been biasing me towards keeping the motor with the truck.

The other route is to hide away the 400 to convert to a 377 for a future 2wd project...
 
#28 ·
The other route is to hide away the 400 to convert to a 377 for a future 2wd project...
I would never spend money to make my engine smaller. You would either need main spacers to install a 350 crank or an aftermarket 350 crank. Either way, why go smaller just to be different?

My next iteration of the 400 will either have 3.875" stroke (or maybe 4.0"). I hear rumors that 4.0" stroke won't fit in the stock block but I like a good challenge. I've run the double humps in both 1.94/.160 and 2.02/1.60 and now run the E-Tec 200. Big difference in old technology (even ported) and out of the box aftermarket. Power past 5000 is noticeably improved and pulls well to 6500. The double humps tailed off past 5500.
 
#10 ·
You could build something similer to whats in my camaro right now. It's so bottom dollar it's hard to believe it runs as well as it does.

Bored 30
5.7 rods
100/1000 cc domed pistons for long (350) rods
Junk smog heads 194/160 valves
comp extreme energy hydraulic cam 490ish lift forgot duration, its off the shelf
1.5 roller rockers
Performer rpm airgap

I have no idea what kind of numbers it makes but it runs very well. My car weights 3420 with me. The only time I ran this motor at martin I was very happy. With 373 gears on stock suspension and junk radials it went 13.001 at 113 with a 2.02 60 ' . With no traction and a junk t5 I had to granny shift I was happy with my junk.

If you want to stop by next week I should have some tires on the back of it and insurence on it. I'll show why you might want to keep those junk heads if you are on a budget and staying below 5000-5500.
 
#19 ·
No mystery here, a good 406 can be built for cheap, you can buy the 210 pro comp aluminum sbc heads from skip white for like $650 in think. Any 450-500 lift hydraulic flat tappet cam and lifters for like $200. Scat 9000 series crank for like $170, not worth turning one for that price IMO. Speed pro hypereutectic flat top or mild dish depending on what compression your looking for. Stock 5.7 rods. Not really difficult to make 400hp, no need to spend a bunch on forged internals for a trail rig application. Seems like people have had pretty good luck with the truck avenger series carbs.
 
#20 ·
Here is the build I was going to use if i was building a 400. the build and dyno specs are in SA design "how to build big inch chevy small blocks."

stock vortec heads "have to get steam holes drilled" 1.94/1.50 valves

9.5 to 1 compression deep dish pistons

lunati hyd. cam
230/230 @.050 .455/.455 lift 114* lobe sep
rpm airgap intake 750 holly
1 5/8 headers 2 1/2 exhaust

525 ft/lb @ 3500 427hp@ 5100
the vortecs make sweet low end expecally with stock valve size they just fall short above 5500 compared to larger runner aftermarket heads. I believe the vortecs are a fair bit better than the old camelbacks both in stock form. my .02
 
#25 ·
You need to decide your goals before anyone can tell you what is a good build.

Crank/balancer, factory crank is just fine. Many may say go aftermarket or to avoid excessively turned factory cranks. In the ten hard years I've flogged my 406, never a failed bearing or crank. Oh yeah, my rod journals are 0.020" undersized too - so taboo. If you want cheap, do not internally balance (if you choose the right components, I question why to balance at all for these rpms). Avoid cheap aftermarket replacement harmonic balancers, they are junk! I have spun two Spectre balancers "apart" (outer shell turns on the inner shell). If you choose to buy an aftermarket crank and/or quality balancer, take the time to check the clearance (micrometer) before you fit it and hone the balancer to size as needed.

On the bottom end, most will say the stock 5.565" rod is junk so many will go with either a factory 5.7" (basically, any other non-400 large journal SBC factory rod) or an aftermarket 6.0" rod. If your goal is less than 5000 rpm, why bother? For sure, it will add extra expense and time to make you feel warm and fuzzy. When building my 406 the first time in 1996, I went with reconditioned 5.7" rods with ARP studs/nuts.

I didn't see anyone address it; once you switch from the stock to longer rods, cam-rod interference should be on the top of your mind. The cam lobes for cylinders 1, and especially 6, will likely be getting friendly with the sides of the top of your rod studs. You will need to grind the sides of the rod and top of the studs for clearance. As long as you're grinding those two, I suggest you match all the rest so the balance is still good.

I ran clearanced, factory 5.7" rods on my first build and it ran to 6000 rpm many times in the first four years of flogging at the drag strip and never failed so there is no question if it is reliable. However, it did not make me feel warm and fuzzy. When I pulled it apart to freshen the rings, I switched to Lunati Street Race rods which utilize a rod cap bolt instead of a stud. When assembling, I was fully expecting to need extra cam clearance for these rods too but was pleasantly surprised to find nearly enough clearance already. I say nearly, because I wanted to make sure if I switched cams, I would still have plenty so I just touched the tops of both sides of the rods with a grinder. These rods were cheap (at the time only $400), relatively light (610 grams, as an I-beam compared to H-beams) and my preference for an engine that was going to see occasional drag strip use to 7000 rpm.

Oil pump; a good stock replacement is fine - avoid high volume, no need. Again, if you want warm and fuzzy, add a high pressure spring if you want - it's cheap. Support the oil pump pickup with an arm that bolts on to the pump and welds on to the pick up.

Piston choice? How could anyone want to run anything but a hyper eutectic in a street or light strip application? Just remember to file fit your rings accordingly or you will be breaking the tops of the pistons off at the ring lands (******** not clearancing the rings correctly for these pistons is how they have gotten mixed reviews). I'm 100% in favor of file-fit rings when assembling engines with non-factory pistons. If you decided to go with 6.0" rods, the piston pin coincides with your oil ring - pay attention to the piston manufacturer's instructions for fitting the rings.

Compression, cam, heads, intake and carb - need to know more about what you ultimately want from your combination.



Cliffs - stick with stock rods and crank, it's cheap and easy if you're only building for 5000 rpm.
 
#26 ·
In regards to Vortec heads...which are really good, have a read through this first.

http://www.2quicknovas.com/vortecheads.html

Stock smog heads are fine if your not searching for ultimate horsepower and they help you to keep your compression down if you're looking to run a smallish cam (which would not be my choice on SB400).

I would hazard to say one of the most common mistakes is to under-cam a 400. The long stroke and high compression (even from flat top pistons) tame larger cams to deliver incredible mid-range torque.

If you are going to run small chamber, small cam you will need a large dish in the piston or you're going to have some pining. A large chamber head (or a larger cam, to a degree) will reduce the need for large dishes in the pistons. Aluminum heads will also help it live with a higher dynamic compression ratio (DCR).
 
#45 ·
I would hazard to say one of the most common mistakes is to under-cam a 400. The long stroke and high compression (even from flat top pistons) tame larger cams to deliver incredible mid-range torque.
To end this hijack (maybe), I would say the second most common mistake when building a 400 is to buy too small of head. I would say that out of the box Torquers are marginally better than the 993 with mild port work and good valves. If you are going to spend the money, get a more efficient head.

Torquers are a $1000 for a pair

http://www.summitracing.com/parts/wrl-042670-1/overview/

Take a good look at TFS

http://www.summitracing.com/parts/tfs-30400002/overview/make/chevrolet

Or Edelbrock

http://www.summitracing.com/parts/edl-60909/overview/make/chevrolet

Pay attention to heads priced per head verses heads priced per pair.

Because of the long stroke and hungry bores, you will have good port velocity compared to smaller brethren with the same cam. Don't be afraid to step up one size larger on the cam than you would have on a 350.

You won't regret either aluminum head for a nice running street engine.
 
#33 ·
Well, for a street machine, I would say that more torque (longer stroke) would be more enjoyable at the rpms it will spend most of it's life at on the street. That's why 383/406 are more fun to drive than a 350. The longer stroke improves idle quality, street manners and delivers respectable horsepower.

What did you think about Edelbrock Performer heads?
 
#43 ·
Myself, I can barely say financially more effective and drag race anything in the same sentence.

If you're running brackets, why bother? Slow it down and let it live.

If your running heads up, someone is going to disregard "financially more effective" and you are lucky to be number two.

Speed costs money, how fast do you want to go?
 
#46 ·
If you can't tell, I'm getting the itch to wrench...(and help spend other people's money, wisely).

In regards to the fuel pump: my preference for the street is mechanical in most cases, stock really works really well (I run a Carter mechanical for the engine by itself). If the stock pump isn't keeping up, check for other causes; rusted fuel lines, pinched hoses or debris in the tank or pick up.

Carb: Again, I'm a fan of simplicity and really like a standard vacuum secondary Holley 750 3310. Look at swap meets, you should be able to find one. Get aquainted with it. Avoid the urge to go gonzo on the carb. Go too big and you'll have weak signal and you'll wonder why you have such large jets and still can't get any color in the plugs.
 
#49 ·
I hear you, I would love to go overkill on my fuel system. In a way, I kind of did. I know that even with the stock pump and lines, I did not drop pressure at the top end with my 440 hp 406; the Carter Strip pump (mechanical) only made me feel warm and fuzzy. To me, return on investment was very low. :sonicjay:

Now, I did add a dedicated electric pump for the spray. :teehee:
 
#52 ·
In all my years messing with small blocks I have learned many things. One of the first things I learned is the long stroke in a 400 kills its rev potential.

You can talk about bigger heads and more ci all day but a 377 will rev so much quicker and higher with good parts it is no comparison imo.
Have you ever built a 400 that revved like a 350? No, it wont spin because of the long stroke...... dont give a fuck what head is on it. It's the rotating assembly that slows it not the amount of air air the heads flow.

We have built 400s and 377s with the best money can buy and the 377 will stomp a 406 every time in the upper rpms. A 377 with cola crank and oliver rods will spin to the moon,happily. A 400 with same parts wont go past 6500-7000 from what we have built, and takes all day to get there.

You need more then 23 ci to make up for 2000 rpms.

Gm made the 400 for trucks and heavy cars, if it had hotrod potential it would have been in camaros, novas, and chevelles.
Its a great torquey motor for a truck but the upper rpm power just isnt there imo.

Unless you actually build a 377 from your 406 you will continue to argue and throw out theries. Fuck theries, they dont win races.

And as far as a street machine goes it depends on the person. Im totally happy with a huge cam, low vacume and less torque down low. I like my street car to sound like a race car and run like one.
The 406 in camaro is quiet, makes huge torque and is a blast to drive. Anyone could drive it. The dz302 I had in it before made no torque,was lumpy and hard to drive.
I enjoyed each motor for what it was. I would bet my 302 put out the same hp with 100 lbs less torque then my 406. In a dragrace I think the 302 was just as fast because I cant hook up with the torque the 406 makes.

The 406 and 377 both great motors and each has their place. If I was building a car I would build a 377 because I am a rpm junkie. If I was building a truck I would build a 420 because torque at lower rpms work best.

Sorry to continue jacking your thread jake. I have always learned more by building shit and seeing what works then by listening to reason and theories. Just my. 02
 
#57 ·
In all my years messing with small blocks I have learned many things. One of the first things I learned is the long stroke in a 400 kills its rev potential.

You can talk about bigger heads and more ci all day but a 377 will rev so much quicker and higher with good parts it is no comparison imo.
Have you ever built a 400 that revved like a 350? No, it wont spin because of the long stroke...... dont give a fuck what head is on it. It's the rotating assembly that slows it not the amount of air air the heads flow.

We have built 400s and 377s with the best money can buy and the 377 will stomp a 406 every time in the upper rpms. A 377 with cola crank and oliver rods will spin to the moon,happily. A 400 with same parts wont go past 6500-7000 from what we have built, and takes all day to get there.
Sounds like you need a different builder.....my 4.1 stroke engine has no issues getting to 7500+ quickly.
 
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