[gamedawg03]

I am about to get my 406 built. I have brodix ik 200 heads from my 383 do i need to get steam holes drilled in them thanks

[vinniekq2]

are you using a GM block?

[gamedawg03]

Yeah dont no casting numbers rite off top of my head but its factiry 4 bolt main already machined and .30 over

[F-BIRD'88]

You can call Brodix direct to get specific advice on drilling your Brodix heads corrrectly for 400SB steam holes.

When I did my 406, with vortec heads, I did not drill for the 400 steam hole.
Instead i simply connected the water pump bypass hose to the water port outlet on the drivers side rear of the block (by the distributor). This is your heater hose. It most be connected heater core or not.
Connecting it at the back of the intake manifold instead of at the front, near the thermostat really helps the colling system function. Eliminates all thermostat open close fluctuation and resulting water temperature spiking on any SBC during warm up and idling. and your 400SBC. My 406 never overheats.

If your intake manifold has the extra water ports at the rear, by the distributor:
I highly recommend you do this simple mod even if you do end up drilling the steam holes in your heads.
many intake manifolds have the extra water ports on the rear of the intake manifold just for this improved cooling system function. GM originally routed the water pump hose just like this on old 60's era engines prior to the emissions era, when they then wanted to the make the chevy engine generally run hotter in an attempt to aid emissions control at the time.

Its pretty simple and it works.

[lmsport]

Originally Posted by F-BIRD'88

You can call Brodix direct to get specific advice on drilling your Brodix heads corrrectly for 400SB steam holes.

When I did my 406, with vortec heads, I did not drill for the 400 steam hole.
Instead i simply connected the water pump bypass hose to the water port outlet on the drivers side rear of the block (by the distributor). This is your heater hose. It most be connected heater core or not.
Connecting it at the back of the intake manifold instead of at the front, near the thermostat really helps the colling system function. Eliminates all thermostat open close fluctuation and resulting water temperature spiking on any SBC during warm up and idling. and your 400SBC. My 406 never overheats.

If your intake manifold has the extra water ports at the rear, by the distributor:
I highly recommend you do this simple mod even if you do end up drilling the steam holes in your heads.
many intake manifolds have the extra water ports on the rear of the intake manifold just for this improved cooling system function. GM originally routed the water pump hose just like this on old 60's era engines prior to the emissions era, when they then wanted to the make the chevy engine generally run hotter in an attempt to aid emissions control at the time.

Its pretty simple and it works.

Why the connection on the drivers side versus the more common pass side connection?

[gamedawg03]

I have a victor jr now but im getting a super victor im not sure if it has it in the back of the manifold also i have a weind water pump but there no place in it or the victor jr for for alternator bracket

[vinniekq2]

If you are upgrading to a super victor,we are talking serious power and high RPM? Are the heads ported a lot? I would probably drill the steam holes,or if you are making big power,think about an after market block.

[techinspector1]

Here is an outline of the procedure if you decide to drill the holes.....
Technical Articles at Greg's Engine & Machine
In my opinion, I wouldn't run a 400 without them. GM engineers found a need for them at low rpm's. Steam pockets would form at the blind corners of the water jackets as a result of the cylinders being siamesed. These pockets of steam would heat that little area and either cause pre-ignition or would cause the motor to spit out the head gasket. I am unsure as to whether or not the engineers tried running a hose from the back of the heads to the water pump, but if they did, it apparently didn't work as well as drilling the steam holes because I know of no factory bypasses, only steam holes. No steam holes are needed if the motor is to see duty in the higher rpm range, such as in a racing application. The speed of the water through the water jacket due to higher water pump impeller speeds will wash away any steam pockets that may try to form. It's only a problem at lower rpm's.

[F-BIRD'88]

Here is apic of trhe rear water port on a tunnel ram.
its on the drivers side, not the passenger side.

I have another pic of a origional 1964 GM 327-375HP fuel injection intake manifold that also has the water port on the driver side specificly, also.
I cannot find it.

Remember this is prior to the emissions era which started in 1966.
Thats when GM started with the hotter engine idle temp design.
to aid emissions. Hotter water temp at idle- generally less idle spark advance
which make the heads and top of the block run hotter at idle.
Thats part of the reason a stock 1970-71 400 SBC has a reputation of running hot.
Truth is all the engines of the 1970 to 1975 era tended to run hot.
By design.
Retarded idle ignition timing.
Makes a big difference. And generally makes any engine run hotter at idle.


See that's the difference--- real world experience and real world context.
Some stuff in this worold was done before the internet came along.
I had a original 400 SBC years ago and went thru all this stuff, then.
Try the water port mod, with or without the steam holes. You'll find it works real good on your 400 and on SBC's in general.

[vinniekq2]

Sounds like instead of steam holes drilled in the heads,that we all know about;you could also look for an antique intake manifold that GM made or a very old cast aluminum intake that was designed for engines that not only preceded the 400 small block,but also preceded the 350 small block.

[gamedawg03]

Im looking for a serious street and strip motor. This is my first serious motor being built, i have had all the machine work done to it i have been looking at rotating assemblies in cnc notorsports website. The one i looked at says its 11.6 cimpression with 64 cc heads .im getting my heads port matched and bowl blended and putting 2.05 valves in them my question is what would be the best way to go for cam for best power on street and strip a retrofit roller or solid roller

[1Gary]

Let's break down the steam hole question.

We know we bore/hone 400's with torque plates mainly because the design of the 400's bores move around alot.

We know the 400's where never designed for high performance use.They where never intended for high compression use.I.E.:76cc heads

We are very sure with increased output=increased heat.

Now I worked at the Chevy engine plant as a engine tester when the 400's where new.Also my racing operation over the yrs in 9.90 cars of 17 last count cars used 7 400's of various size.All of them with steam holes drilled.

We know mainly because of the well documented issues the OEM 400 blocks have is the reasons why the aftermarket blocks where designed as they are.

The summation of this is if not for the leakdown sealing issues the 400's have,there isn't a sound reason not to have the steam holes drilled.

As a side comment.Any suggestion not to drill those holes is confusing as the reason.Or to run bypass hoses.At best that is very dated.At the worst it is to draw attention to themselves knowing it is argumentative post.Certainty drilling the steam holes is a proven preventive method.

If your asking which cam type would be the king of the hill given your SCR,a roller solid lifter with a rev kit is the way to go as long as you don't mind setting the valves.Certainly you have to have the springs for it and check the clearances.

[vinniekq2]

when your heads are finished,have them flow tested.Then what 1gary said,the solid roller that matches your cylinder head flow will be the better choice.

[1Gary]

Had me back tracking here.Long before you buzz this 406 up,need to know that the rods you have/rod bolts can cover that kind of stress.Also IF you go solid roller lifter cam/kit,most are going to leave something on the table on the lower rpm ranges.Almost all are going to need a loser T/C and gears.

BTW-love that brand name heads.We have used them(maybe not this model,but)have had nothing but good results.

[gamedawg03]

I was looking at the lunati voodoo 60132 and 60133 cam i think they have complete kits to its going in a 87 monte carlo ss 7.5 10 bolt 4.10 gear but looking for ford 9in