i picked up a 4-bolt main 400ci SBC.
and i have a line on some 461 casting heads.

i've heard that i should be careful selecting heads for the 400ci and that i should pay close attention to the head gasket, but i haven't found any information about WHY i should be careful.

maybe something about the longer stroke?

the heads are 2.02 intake and 64cc


what's the big deal?

i picked up a 4-bolt main 400ci SBC.
and i have a line on some 461 casting heads.

i've heard that i should be careful selecting heads for the 400ci and that i should pay close attention to the head gasket, but i haven't found any information about WHY i should be careful.

maybe something about the longer stroke?

the heads are 2.02 intake and 64cc


what's the big deal?
400 sbc have larger steam holes above cylenders, have to make sure heads and gaskets match larger steam holes or burn up happens. 400 sbc is typicaly short rod large bore low compression motor those heads should be ok, make sure all clearance areas are ok.

mobilemech

I would take the rotating assmbly and put in a 350 to make a 383 and put on some vortec heads. more power and no heat issues.

Just my 2 cents

Skeeter

I would take the rotating assmbly and put in a 350 to make a 383 and put on some vortec heads. more power and no heat issues.

Just my 2 cents

Skeeter
not cost effective to have machine work done to crank and balencing, cheaper to buy stroker crank ready to go. right on for 383 set up though.

mobilemech

400 sbc's can also be a PITA due to the siamesed cylinder bores they have.

Iv'e built a couple 400s and never had any problems overheating or head gaskets issues. Whatever heads you use, make sure the steam holes are there. I've used stock FelPro head gaskets on mine. One 400 I had, drove it back and forth to Canada and Bingo where I live, put 60k miles on it, middle of summer and through the winter. Motor had at least 200k when I put it in, the only problem I had was now and then I would break a rocker, the cam was the max lift for the stock valve springs. Last 400 I had, used 350 rods, stock everything else, used TBI heads, all stock TBI stuff and ran like a raped ape. Got another 400 for the burban, using Vortecs and eventually TBI. The longer stroke increases the qeunch time, kinda like high compression, so if shitty gaskets, or overheated it will blow the head gaskets.

nskeeter: i didn't ask how to build a vortec stroker. but i'll take your .02... hell... i'll take ALL your lunch money. :flipoff2:

mobilemech: right on.. searched for the steam hole info and found out exactly what needs to happen! thanks brother!

b454rat: sounds like you just nicknamed my soon to be motor! it's going to get longer rods (to avoid cam clearance issues). i've already got crane roller tips. and i'll be doing some sort of EFI! thanks for the info!!! appreciate it

all hail RAPED APE

http://www.gregsengine.com/350to400.htm

You have to worry about cylinder wall deflection on a large overbore. Not sure if 0.020" or 0.030" is the limit.

Max safe overbore for a 400 is .030. I had a 408 (.040 over) in a 3/4 ton, and with a new rad, fan, water pump still ran hot. The TBI406 that I had in my 90 had a new pump and rad, and never got hot. It had a cowl hood, so that might have helped some. The setup that I had in the TBI406, stock crank, stock 5.7" rods, KB hyperwhatever pistons, with IIRC a 22cc dish. Because they were aluminum and with a dish, the bottom of the piston hit the top of the rod. Was easily fixed by grinding the tops of the rods. Had it all balanced and was good to go.

Do some research on cam lobe to rod bolt clearance in a 400 too.

Clearances must be checked when you change rod lengths. Almost like a 383, where you check rod clearance at the lower water jacket and rod to camlobe clearance. On a 383 you would also check clearance at the oil pan rail for the rod bolts/caps/nuts (depending on what rods you use...bolts vs. cap screws....the cap screws generally give more clearnace). On a 400 with longer rods, that area of concern, generally won't change, unlike the 383 where you are using a crank with a longer stroke.

Now, I wish people would stop generalizing the 400 as a bad motor because it overheats. They were great motors and run well. They can overheat if not maintained well and/or if heads were changed and the steam holes were not drilled into the new head. They also can't take as much overbore as the others in the SBC family. The overheating 400 SBC IMO is overrated when these facts are ignored. If done right you'll have a fine motor that can build TQ quickly at low revs. They are a large bore long stroke motor that were used in heavy fullsize cars and trucks.

THAT'S why i want to use the 400!
low rpm torque #s!

i'm not overboring... i'm not even boring.
i'm using 5.7" rods, and i'll clearance check everything before i run it.


any suggestions for pistons?

I ran a 30 over 400 with vortec's and 5.7rods for 5years with -22cc dish kieth blacks and a 228/235 @050 hydraulic none roller on a 117l/s, stock ratio rockers and TPI. Zero decked to keep the quench area tight and reduce detonation. And this combo worked really well for wheeling cranking compression was about 190psi if this helps your piston choice. These pistons were noisy when cold tho.

This is what I got
http://i57.photobucket.com/albums/g210/RockCrawlingHawaii/DVC00001.jpg
400, bored & stroked to 421, forged bottom end, running 'Pane and Juice.
:grinpimp:

Oh Ya, it's being swap from the heep to the K5, where it should be.

400 sbc are great engine's with the right combo! Had a .030 over 400 = 406 that ran really strong, it had 5.7 rod's (.135 longer then stock) whitch make the motor much smoother, big lift small duration cam! For the heads all you have to is drill the hole's in the head between the cylinder's, just take a good 400 head gasket and match it up to the head, measure the hole in the block and the head gasket take a drift punch mark the head and drill the heads! I think for the head's your using (64cc) you should use a dish piston to try and keep the comp. down around 10:1 or less and you would have a easy 400-450 H.P. and the engine is still fairly mild!
The 406 that I ran had 5.7 rod's, flat top piston's (11:1 comp.) .550 lift .283/.293 dur. cam,Chevy bow-tie head's 2.02/ 1.6 valve's 64cc! Very strong engine made about 470/490 H.P. but the compression kept me limited to just running any kinda fuel, it would ping like hell on 93 octane and would torch a head gasket now and then! That's why I would keep the compression lower, around 9.5:1/10:1 max!

[QUOTE=dezrocks;6279536]For the heads all you have to is drill the hole's in the head between the cylinder's, just take a good 400 head gasket and match it up to the head, measure the hole in the block and the head gasket take a drift punch mark the head and drill the heads! QUOTE]


Agreed...except I believe the holes need to be drilled at a given angle. Not all IIRC but certain holes need to be drilled at an angle. I think the three intake holes are drilled at a 40-45 degree angle towards the exhaust side. And the three exhaust holes are drilled straight down towards the top of the head, remember the angle of the head as it sits on the motor for drilling to the "top of the head". I don't think it would be straight down depending on your positioning of the head when you drill it.


PS. here ya go....from U2slow post above......http://www.gregsengine.com/350to400.htm

This is what I got


WTF is on top of your manifold?!?!?
something to do with all the nox and pane?

WTF is on top of your manifold?!?!?
something to do with all the nox and pane?

Ya, something like that:shaking:

WTF is on top of your manifold?!?!?
something to do with all the nox and pane?

propane setup

with vortec head holes need to be drilled in the head to match the water holes in the block. this is an easy, if memory serves its a 23 degree hole, just lay the 400 gasket on the head, mark the missing steam holes and drill. that is what has caused the notorious over heating issues with the 400 sbc. if you do that you shouldn't have any heat issues.

a 400 bored .30 over is a 406

a 350 crank in a 400 is a 377 not a 383. you do loose tq but you will get a very high reving engine, similar to a 327.

and this i have read over and over, and really don't understand it, but apparently 2 bolt 400 blocks are supposedly stronger than 4 bolts. i have no idea how, but i have read that in several places.


micky

2 bolt main use splayed bolts. the 4 bolt main does not.


bowtied_mickey... the intake side steam holes need to be drilled 40* toward the exhaust side.

2 bolt main blocks arent splayed. they have more material in the main webs. ideally, if you want the strongest 400, get a 2 bolt block and have it drilled for 4 bolt caps or splayed caps.

As I understand it, the 4-bolt 400s have little benefit because of the minimal 'meat' in the area they anchor into.

If you require 4-bolt mains on a 400, adding splayed mains to a 2-bolt block is the only way to go.

2 bolts with aftermarket splayed caps are much stronger than a stock 4 bolt....(who the hell would use stock 4bolt caps drilled into a 2bolt block when 4bolt splayed are sooo much stronger ,easier to obtain, and not much $$).......yes due to the meat in the main webbing on the stock 4bolt weakens that area making it crack prone.

The 2bolt block in fine for some pretty decent HP and it is when RPM gets crazy you'd be looking at the splayed 4bolt route....IMO.

As for drilling the non 400 heads....HAS TO BE DONE.....read up a few posts, I mentioned it the angles there with a link provided by U2slow.

Again, the 400 makes a great TQ motor for heavy objects (trucks cars what have you). For lowend TQ it is hard to beat the stroke and large bore design that the 400 offers. The large bore makes any head breathe a bit better by naturally unshrouding the valves. They do not SIMPLY overheat by looking at them crosseyed as the myth goes.

new build specs:

400sbc
.30 over
forged 22cc dished pistons
5.7l Hbeam rods
scat9000 internally balanced crank

vortech heads
scoggins vortec tpi ram
either F.A.S.T. or MegaSquirt

still undecided on cam... any cam experience in modded or unmodded vortec heads?

sounds like a good combo. in "how to build big inch small block chevy's" they have a similar setup only with a carb. it makes around 475hp and 530lbs of torque if my memory serves me correctly.