Block decking, and head alignment
12-05-2003, 11:39 AM
#1
Member
Thread Starter
Join Date: Jul 1999
Location: Marshall,IL
Posts: 347
Likes: 0
Received 0 Likes
on
0 Posts
Car: 82 & 91 Firebird
Engine: 400 & 355
Transmission: TH350 & 700
Axle/Gears: 4:11 & 2.72
Block decking, and head alignment
If you have a block decked how much material needs to be removed, before you have to have the heads, remachined to align with the intake.
My 400 needs 30 thousandths removed.
Thanks
Spud
My 400 needs 30 thousandths removed.
Thanks
Spud
12-05-2003, 12:12 PM
#2
Supreme Member
Join Date: May 2001
Location: Pitman, NJ
Posts: 2,009
Likes: 0
Received 5 Likes
on
4 Posts
Car: '89 IROC-Z
Engine: Canfield 195 headed 358ci
Transmission: TH350, Art Carr 9.5"
Axle/Gears: 3.92 Dana 44
My block was 0-decked and required no machining to the intake or heads for them to align.
12-05-2003, 02:00 PM
#3
TGO Supporter
i've never had a problem with intakes when i removed metal from the block. just got a set of heads and pick up block next week that have both had metal removed so i'll see what that does
12-05-2003, 02:12 PM
#4
Supreme Member
iTrader: (1)
Join Date: Jun 2001
Location: Dale City, VA
Posts: 1,668
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 GTA and 85 IROC
Engine: 355
Transmission: gear jammer
Axle/Gears: 4.11
There is a formula for that. But I'll be damned if I can remember it now. I'll look through some notes.
0.030 is quite a bit, but I don't think you'll have any major problems.
0.030 is quite a bit, but I don't think you'll have any major problems.
12-05-2003, 02:52 PM
#5
Supreme Member
iTrader: (35)
Join Date: Feb 2003
Location: Albuquerque, NM
Posts: 1,229
Likes: 0
Received 3 Likes
on
2 Posts
Car: 1966 El Camino Custom
Engine: 350
Transmission: 200R4
Axle/Gears: 3:73 12 bolt with Brute Strength
Your block should have come from the factory approximately with a 9.025" deck. 030" would probably put you below 9" which is the standard that most pistons are set for as far as comp. height. Your pistons will probably be just above the deck after being machined.
The standard accepted head deck to block deck clearance for steel rods is about .035". To maintain this on a block decked below 9", you will have to run a fairly thick head gasket to maintain that .035" clearance. Any quality head gasket in the .045" to .060" range would be good. DO NOT RUN A SHIM GASKET AFTER YOU GET THE BLOCK BACK!!
You also might consider running the Moroso plug deck stiffeners. They are just a NPT 3/4" plug with a 5/16" hole for head cooling. Typically, because I use my cars just for street use, I will drill these out to about a .400" hole. I like the deck strengthening but like my heads to cool normally.
The standard accepted head deck to block deck clearance for steel rods is about .035". To maintain this on a block decked below 9", you will have to run a fairly thick head gasket to maintain that .035" clearance. Any quality head gasket in the .045" to .060" range would be good. DO NOT RUN A SHIM GASKET AFTER YOU GET THE BLOCK BACK!!
You also might consider running the Moroso plug deck stiffeners. They are just a NPT 3/4" plug with a 5/16" hole for head cooling. Typically, because I use my cars just for street use, I will drill these out to about a .400" hole. I like the deck strengthening but like my heads to cool normally.
Last edited by wesilva; 12-05-2003 at 03:53 PM.
12-06-2003, 01:32 PM
#6
Supreme Member
Join Date: Apr 2001
Location: USA
Posts: 4,969
Likes: 0
Received 0 Likes
on
0 Posts
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Straight from John Lingenfelter's book
John Lingenfelter on Modifying Small-Block Chevy Engines, pg. 95
John Lingenfelter on Modifying Small-Block Chevy Engines, pg. 95
Anytime either the block deck surface or cylinder head dack surface is machined, this changes the relationship of the intake manifold and cylinder head sealing surfaces. To restore this relationship and improve intake manifold gasket sealing, it's often necessary to mill both intake port sealing surfaces as well. If the heads and/or block is milled less than .020-inch, milling the intake is usually not necessary. All dimensions are in fractions of an inch.
Block/Head.................Intake Manifold
....................................Side...Bottom
.010---------------------.012----.017
.015---------------------.018----.025
.020---------------------.025----.034
.025---------------------.031----.043
.030---------------------.037----.052
Block/Head.................Intake Manifold
....................................Side...Bottom
.010---------------------.012----.017
.015---------------------.018----.025
.020---------------------.025----.034
.025---------------------.031----.043
.030---------------------.037----.052
12-07-2003, 10:44 AM
#7
Member
Thread Starter
Join Date: Jul 1999
Location: Marshall,IL
Posts: 347
Likes: 0
Received 0 Likes
on
0 Posts
Car: 82 & 91 Firebird
Engine: 400 & 355
Transmission: TH350 & 700
Axle/Gears: 4:11 & 2.72
I have that book, Maybe I should have a refresher course, and re read it.
Thanks
John
Thanks
John
Thread
Thread Starter
Forum
Replies
Last Post
383backinblack
Transmissions and Drivetrain
8
08-15-2015 06:36 PM
rithsleeper
Engine/Drivetrain/Suspension Parts for Sale
0
08-11-2015 07:55 AM
