Thread: Advice for a 454 newbie

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Originally Posted by The_hun

Could you give me any direction on how to properly measure them? As well as a proper procedure to measure the block deck height? Thanks

Here is the proper way to measure block deck height on a disassembled block with no main bearings installed. This is a new tool that is available from Jamison Equipment. It is a special tool for the procedure because of the rounded lower anvil. If you use a standard dial caliper or standard electronic caliper, the lower anvil will be flat and you are trying to measure a rounded surface, so your reading will be off. As it says in the description of the tool, you would add the radius of the main bearing bore (less bearing) to the reading from the tool. I don't expect you to buy a $350 tool, that's why I said take the bare block to an automotive machine shop and have them to measure it. You will come away with 4 measurements, cylinder 1, cylinder 2, cylinder 7 and cylinder 8. This will allow you to see if the block has been machined square. If it is not square, the heads will be lolly-gagged on the block and the manifold will not stand a chance of sealing up all 8 cylinders.
BLOCK DECK HEIGHT MEASURING TOOL *NEW* | Jamison Equipment

The main bearing bore on a Mark IV big block Chevy is 2.7488" to 2.7495", just a hair under 2 3/4", so you would add 1/2 the bore measurement (less bearings), or about 1.3745" to the figure you found with the tool. This will give you the BLOCK DECK HEIGHT from the flat part of the block deck where the heads bolt on, to the CENTERLINE of the main bearing bore. The blueprint measurement from Chevrolet Engineering is 9.800", but you have no idea if the block has been machined or not in the past. At best, it is 46 years old and you have no idea how many hands and how many machine shops it has been through or what has been done to it. That's why you need to know.

Now, if you are hard-headed and want to do everything yourself that is possible to do, go to ebay and purchase a used 12" dial caliper. Do not be swayed by anything that anybody has good to say about an electronic caliper unless you own a machine shop and have to measure in ten thousandths of an inch every day. I have owned digital calipers in the past and every time I reached for one to use it, the batteries were dead. A dial caliper is bulletproof, works every time. While there are shorter dial calipers available to you, none of them will be long enough to measure the BLOCK DECK HEIGHT of any modern V8. A little 4" tool will be so handy that you won't know how you got along without it, if you do anything related to automotive. Here is a copy of ebay from Tuesday night, Jan 7, 2020........
http://www.ebay.com/sch/i.html?_from...icator+12+inch

If you end up measuring the block yourself, I'll give you my phone number so that we can walk through it together.

Don't be concerned about the accuracy of a used dial caliper that looks too cheap to be any good. Any of them that you buy will measure to the nearest 0.001" (one thousandth of an inch) and that's close enough for most automotive work, unless you're building motors for a living or race motors, where you would want to be able to measure to the closest ten thousandth of an inch (0.0001") Purchase one the measures 0.100" (one hundred thousandths) for each revolution of the needle. 10 revolutions equals one inch.

Here are some other photos that will maybe clear it up for you........
http://www.clubhotrod.com/chevy-big-...31.Qw0fjNJJ9j8

Let me clear one thing up for you that everybody gets wrong.
BLOCK DECK HEIGHT: The distance from the block deck where the heads bolt on to the centerline of the main bearing bore.
PISTON DECK HEIGHT: The distance from the piston crown to the block deck where the heads bolt on, with the piston at top dead center. It is rare to find anyone who can tell you the difference between these two parts of a motor. Learn these terms and speak them with confidence. You may pizz off a few people, but in the end, you'll be correct and they will not. So, when someone asks you about "DECK HEIGHT", ask them if they're referring to block deck height or piston deck height.

Oh, and lest someone tries to confuse you with PISTON COMPRESSION HEIGHT, tell them that it is the measurement from the centerline of the piston wrist pin to the top of the piston. To measure this with a dial caliper, you would hang one of the anvils on the uppermost wrist pin bore and the other anvil onto the crown of the piston, then add half the wrist pin bore. On a BBC, this measurement is 1.640" from the factory. This measurement is relative to the piston itself and has nothing to do with any other motor parts, except for calculating "STACK", the measurement of the piston compression height, connecting rod length and the radius of the crank stroke (2.000" for a 454). Adding these three values together will give you the STACK HEIGHT. If you have the stack height and the block deck height, you will know how far down in the bore the piston is at top dead center. This is critical for finding the gasket thickness needed.
http://www.clubhotrod.com/chevy-big-...30.X8Yuoy4-eRI

You will notice that when I write a numerical value in decimals, I put a zero in front of the decimal point. This tells the reader that this number is less than one inch. If you just wrote .001", you could not be sure that the writer of the number meant it to be smaller than one inch or if he just forgot to add the whole number to it. 0.001" or 2.001" means something, .001 is ambiguous. My father was a tool and die maker, so I have been fiddling with this stuff all my life and want to teach you correctly.
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