Visit The Dirt Forum for More Information

Author Topic:   406 cid
MOD RACER#93
Dirt Freak

Total posts: 251
posted January 23, 2001 11:44 PM
I just got a hold of a chevy 400 motor. I want to build a 406. There was mention of block filler on another post, and I was wondering if I will have to use this? Also, I want to use 5.7 or 6.0 inch rods. Is there a problem I will run into using these longer rods? One more question, what about the external balance? If I have everything balanced I should'nt have to worry about this...right?

awkwardjeff
Dirt Freak

Total posts: 219
posted January 24, 2001 01:18 PM

mod racer 93, block filler??? depends on what you are trying to build, for 12.5 to 1 OR LESS compession you don't need the core fill the bottom, unless you are scared to hit water when grinding the oil pan rail.......you will need to get after the oil pan rail where the rods swing threw to get the clearance you will need. a 6 inch rod, because the angle of the rod changed when it gets close to the pan rail the bolts are a little more in the way then if you run a 5.7 rod.
You need to grind the clearance either way. with a 6 inch rod you need to grind a little more.
Balance ???? are you planing on buying a crank kit and bolting this together yourself?
If you use a stock crank you need to have a 400 balancer on the front and a 400 flywheel or 350 flywheel with the bolt on weight.....
most after market cranks are internaly balanced, again this depends on bob wieght and many other things...........just bring every thing you plan on useing to a good reliable shop and have them check and balance every thing together.........
There are too many varations of this to say yes or no........
WISSOTA has changed the rules for us people in the Modified class and today there are a ton of 400 blocks for sale along with a bunch of 406 motors with great parts cheap.
I'm not getting rid of my 406 yet but I have sold all my blocks already. I kept 2 blocks just in case.............but if you would like a web site for some stuff for sale in wissota....... WWW.ALLTHEDIRT.COM

MOD RACER#93
Dirt Freak

Total posts: 251
posted January 24, 2001 07:04 PM
Thanks for the reply jeff. I was looking to to get a 'balanced rotating assmbly' and it said it came with a dampner and balance plate. I was looking at the 5.7 rod combo, because this kit is cheeper than the 6.0 inch, and I thought they would be better than the stock 400 length rod... It is going to be around 12.5 to 13.1 compression...I hope. Im not very familiar with the block fill, so if I dont have to use it, it would be easier for me to handle...The last 355 I had machined, the guy did this stuff on the side after work in his shop behind his house...I just carried everything to him and said take care of it(machine work, getting it balanced, clearanced etc.) Then I put it together...Since then he moved to the country and sold all his equipment...bummer...Thanks again for the help.

p.s. Anymore would be very appreciated...

awkwardjeff
Dirt Freak

Total posts: 219
posted January 24, 2001 07:26 PM
The block filler is no big deal, just like making a cake mix and pour it into the block with all the soft/freeze plugs out. Only fill the bottom of the block up too the soft plug holes, otherwise you will have a cooling problem, this must be done before any machine work is done to the block, otherwise if done after being bored the holes will not be round.......
go to the street stock page and look at the post concerning 400 blocks I gave some advice on making the deck of the block stiffer there, you will NEED to stiffen the deck with that much compression.
I know a lot of people that like the 5.7 rod 406 rather than a 6 inch.......like ANY motor cam selection is very important.
If this will be your first time with a 406 you SHOULD still get a local machine to help clearance the block properly. ............
Any more help I can think of I'll just add to this post..........Jeff

WPP
Dirt Full Roller

Total posts: 46
posted January 25, 2001 08:08 AM
Do you know anyone that has 400 block I need one

MOD RACER#93
Dirt Freak

Total posts: 251
posted January 25, 2001 06:57 PM
Jeff says to go to WWW.ALLTHEDIRT.COM that there were some guys selling 400 stuff, because of a rule change. I am going there after I get done here. I really wanted a 350 4-bolt block for buid a 383 but this VAN(have yall ever pulled a motor out of a van??? Its a blast) we bought just had a 400 so were gonna try to make the most of this MIGHTY MOUSE. I have scrapped the balanced rotating idea, and have decided to go ahead and get the pistons I want, and crank and rods, and when I get through making sure everything is right, take everything to be balanced. I really appreciate the help Jeff.

awkwardjeff
Dirt Freak

Total posts: 219
posted January 25, 2001 08:09 PM
I've got a couple blocks left......say $175 each for the untouched blocks......saving one with splayed caps and bored and decked already......this was a 377 I robbed the crank and rods for something else after we had a few 406 motors......would sell this block for say.....$500......Anyone wanting a block will need to pay up front and ship at thier cost........Jeff
On removing a motor from a van......take a sawzall and cut the radiator saddle on each side and it will fit out the front.....I did this a few years ago, where the hold down goes on top the radiator I split the saddle in the center of the bolts of those hold downs so after I put the motor back in you couldn't even see I was that LAZY.......LOL
TOO MUCH WORK TO TAKE IT OUT THE BOTTOM.
Jeff

tls88mod
Dirt Roller

Total posts: 24
posted January 25, 2001 11:03 PM
The only advice I have is to plumb a water line from the center of the heads to the thermostat housing. There is a boss in the head between the center exhaust ports thats kind of square and its surface is 90 deg to the blocks deck. Drill a hole and tap an 1/8" pipe thread into the head. Then put a 90 deg fitting in there and point it towards the front of the motor. Then run a 5/16" rubber hose up to a fitting in the spacer block between the intake and the thermostat.

The hottest part of a 400 engine is between the center cylinders because water does not pass between them. This lets the hot water out quicker and saves on premature head gasket failure. Also, I would suggest using Felpro #1034 head gaskets, they are the best we've found.

Back to the Archives