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manchildau65 04-04-2009 10:46 AM

406 sbc, build questions
Hi, I'm a new member and have some basic questions about a 400 sbc that I'm putting togethor. The following is the information I have about the engine:

Serial Number: 330817
Bore: 0.030" over
Main Caps: 2 Bolt
Crank/Connecting Rods: Stock

Serial Number: 14014416
Intake: 2.02 SS
Exhaust: 1.60 SS
Push Rods: Stock
Valve Springs: Doubled? (one inside of another)
Valve Guides
Tapped/Studded Rocker studs
Combustion Chamber: I was told 64cc but the 416 head is 58cc right?

Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 3,000-6,500
Intake Duration at 050 inch Lift: 234
Exhaust Duration at 050 inch Lift: 244
Duration at 050 inch Lift: 234 int./244 exh.
Advertised Intake Duration: 292
Advertised Exhaust Duration: 302
Advertised Duration: 292 int./302 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510 in.
Valve Lift with Factory Rocker Arm Ratio: 0.488 int./0.510 exh. lift
Lobe Separation (degrees): 114

Ring dimensions 5/64, 5/64, 3/16
Dome shape: .135 dish; 4 valve reliefs
Compression dist 1.560
Deck Clearance .025
Skirt Clearance .0015

So, I'm sorry to data dump but this is the engine I recently purchased as is. The application will be for a pickup I'm building (K30) and will be using it for fun mostly, definitely want to run pump fuel in it. I've had it running previously with 93 octane and it was very strong with great oil pressure.

First question: is this set up any good? or what should be changed?
Second question: I need a head gasket, what gasket should I get?
Third question: what kind of numbers can I expect from it?

Thanks guys for any input, I'm a novice, with very limited money (recently married) and just want something fun and reliable.


manchildau65 04-04-2009 11:48 AM

I also do not have a carburetor... I take that back, I have a Holley 600 or 650 (don't know the part number off hand) but it was given to me and needs parts/gaskets and I think it is too small. Any suggestions for a budget carb?

dawg 04-04-2009 11:51 AM

get a felpro head gasket with steamholes for sure
you set up seems pretty good but vacum might be borderline
im betting 430hp guess.

ap72 04-04-2009 01:09 PM

Those heads can't support 400hp UNLESS you take the time to port them out- then they're pretty decent. That cam looks little big for your intended use, but it will run fine, just not have as much low end as I would prefer.

My only suggestion is to port the heads. I don't believe 305ho heads had steam holes so you wouldn't need a gasket for them unless you had them drilled- which would also be a smart move.

Summit has a budget line of carbs that came out recently- I believe they have a 750 for like $250, it would be plenty for that.

LASTLY, measure your piston dish volume, your chamber volume, and set your quench distance to about .040"- you can use that to figure your compression. No more than 10:1- preferabley around 9.5:1 for a daily driven truck.

manchildau65 04-04-2009 11:38 PM

Boring the Steam Holes
What's involved with boring the steam holes into the 416 head? Is it easy enough I can do it in my garage or do i need to send them to a machine shop?

Also, I failed to mention I have roller tip Crane rocker arms with different ratios for the exhaust and intake valves... don't remember what they are but will post up tomorrow when I check.

What's involved with Porting them? again, can I do this myself or is this something i need to have a shop do?

Thanks again for the replies and I appreciate any input!


backardracer 04-04-2009 11:58 PM

its not hard to put the steam holes in them just line a head gasket up and drill
take you time to line every thing up i've done it a few time havent had any problems with them. now porting your head is a nother thing that alot harder to do get a good grinder alot of books and some one that has been doing it for years all in the same room you could give it a shot but start with a junk set because you will mess the first piar up
and they need the steam holes or it will over heat hard on head gaskets

F-BIRD'88 04-05-2009 12:01 AM

The 416's will need the porting work along with the larger valves. Yes you can do the porting work at home. the Biggest skill you'll need is the patience to see the job through. I like to go with a 1.94x 1.60" valves set in these heads but your's already have 2.02's so..... The heads need a good bit of porting but are not too bad when all done. (230ish cfm, you will get dirty)

With the chamber edge relieving required for the larger valves the volume will be around 62ish CC. You have to cc your heads to know for sure.
use the 1.6 rockers on the intake side.
Stock converter: use a 218-230 cam EG comp XE262, 275DEH or speed pro equivelent cam

The required steam hole drilling is straight forward and can be done at home or sent to the local machine shop.

manchildau65 04-05-2009 12:02 AM

Steam Holes
Nothing more besides lining up the gasket and drilling? How deep? at what angle? what size? I guess I'm nervous, these heads have had a lot of work done to them (probably too much for a simple 416 head) so I'm a little scared with just drilling some holes... Anyone have pictures?

techinspector1 04-05-2009 12:03 AM

backardracer 04-05-2009 12:07 AM


Originally Posted by manchildau65
Nothing more besides lining up the gasket and drilling? How deep? at what angle? what size? I guess I'm nervous, these heads have had a lot of work done to them (probably too much for a simple 416 head) so I'm a little scared with just drilling some holes... Anyone have pictures?

drill the hole strate the hole should be the same size as what in the block not hard to do

F-BIRD'88 04-05-2009 12:27 AM

If you have the rear water ports on your intake manifold you can employ them too.

manchildau65 04-05-2009 05:21 AM

The attached tech article is extremely informative! The only detail missing is the depth of the holes... do I just drill until I've cleared through to the water chamber?

OK, another newbie question, I've never ported a set of heads. Can you guide me to another tech article on the right procedure?

With the engine torn down, would I be better off in the long run to suck up the 80 bucks or so and buy another hydraulic cam? or do you think the one I have will produce some good power with my set up?

Thanks again - joining this site has proven to be invaluable!


manchildau65 04-05-2009 07:46 AM

Carb and Intake
The engine currently has an Edelbrock Performer RPM, since I need a carb with atleast ~710 cfm I'm looking at staying with Edelbrock and buying the 1407 750cfm unit. Any opinions? I've had good luck with Edelbrock in the past, they seem to be the easiest to set up and maintain... to a novice.

Thanks again for any input.

cobalt327 04-05-2009 07:57 AM


Originally Posted by manchildau65
do I just drill until I've cleared through to the water chamber?


manchildau65 05-10-2009 05:47 PM

So it's time to button the engine back up, and I've a couple questions prior finishing everything.

1) I thought that chromoly rings were a great idea when I first started this build years ago, however, even now as I'm in the process of refreshing the engine the oringinal cross-hatching is still present. Should I tear it further down and replace the Chromoly rings with a standard set? This engine will be a toy, meaning I won't be putting many miles on it but will be running it hard.

2) I need a set of head gaskets, in my opinion I have too high of compression so I'm looking to reduce the ratio if in any way I can. What do you think of these head gaskets for my application: SUM-111505 ?

As always, I appreciate any and all feedback.

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