Engine decking
Instructor
Joined: Nov 2011
Posts: 202
Likes: 160
The only way to know is to measure from the crank centerline to the finished deck surface. Your crank throw, rod length, bearing thickness, piston side clearance (rock) and pin height determine your piston to deck clearance, depth or protrusion. Can you see remnants of the VIN stamp? Do you have a known rotator to mock up?
Brandon Unklesbay
All-In Performance, LLC
Brandon Unklesbay
All-In Performance, LLC
Le Mans Master
Joined: Feb 2008
Posts: 6,482
Likes: 1,918
From: Folsom CA
They usually only take .005 off the deck when decking a block. I would order pistons that are not destroked and check the deck height once assembled. If your pistons are up out of the hole you can use a thicker gasket but I bet you will be fine as is.
Le Mans Master
Joined: Nov 2003
Posts: 5,772
Likes: 694
From: Maryland
St. Jude Donor '05, '09, '15
To measure it yourself, use a pair of 12 in. Calipers and a Dial Bore Gauge. Be sure to measure all the cylinders. The height will vary slightly between the cylinders. Stock SBC deck height is 9.025 ".
- Install main caps without bearings.
- Measure the main bearing bore.
- Divide the bore measurement by 2 to find the radius.
- Hook the jaw of the caliper on the main bearing bore.
- Measure up through the cylinder to the deck surface.
- Add the bore radius to the caliper measurement
- This is your deck height
Race Director
Joined: Apr 2005
Posts: 10,179
Likes: 2,306
From: Wesley Chapel, FL Las Vegas, NV
Thicker gasket maybe adverse to quench
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
you have to be pretty good with those measuring devices to see a plus or minus .005.
some blocks may have been cut only once, and others a few times depending on how many rebuilds. Thats the risk of buying used.
buying specially cut pistons or rod lengths will cost you more than the money saved buying a used block. your cheapest and quickest solution is to buy custom thickness head gaskets.
decking a block is almost always unnecessary and usually only needed to make the machine shop owners boat payment.
some blocks may have been cut only once, and others a few times depending on how many rebuilds. Thats the risk of buying used.
buying specially cut pistons or rod lengths will cost you more than the money saved buying a used block. your cheapest and quickest solution is to buy custom thickness head gaskets.
decking a block is almost always unnecessary and usually only needed to make the machine shop owners boat payment.
Le Mans Master
Joined: Feb 2008
Posts: 6,482
Likes: 1,918
From: Folsom CA
Most of these engines are rebuilt with standard automotive head gaskets which are all .039 thick even though the factory metal shim gasket was .015 thick. If you put the non destroked factory type pistons in your block and they protrude a little you have the aftermarket standard gasket option to gain the needed clearances. I doubt highly any block was cut more than a standard .039 gasket would correct. No doubt quench helps an engine run well but as stated, most of these engines are built with the aftermarket standard .039 gasket and those engines are out there running just fine. The aftermarket builds all engines with the thicker gaskets for just this reason, they do not know the history or how many times the block and heads have been worked on.
Best case would be take your block and have it square decked and have them give you the actual measurements then you know you are starting with a block that is exact on all 8 cylinders and know your deck height. That costs money but for performance builds it offers extra performance. BTW: Factory brand new engines were not perfect, many were way out of spec for deck heights and they all ran, some just ran better. This is why people pay to square deck blocks before a build.
Best case would be take your block and have it square decked and have them give you the actual measurements then you know you are starting with a block that is exact on all 8 cylinders and know your deck height. That costs money but for performance builds it offers extra performance. BTW: Factory brand new engines were not perfect, many were way out of spec for deck heights and they all ran, some just ran better. This is why people pay to square deck blocks before a build.
