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Thread: What Is The Difference
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05-20-2005 #1
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What Is The Difference
A Friend Of Mine Just Recently Aquired A Bb 454 From A Friend. His Friend Told Him The Motor Came Out Of A Old Box Truck. If I Remember Correctly The Engines In Old Box Trucks Were Called Tall Blocks. So What My Question Is What Is The Difference Between The Tall Block And The Standard Block. He Is Wanting To Build This Motor And Is Looking At The Holley System Max Kit. Can He Use This On A Tall Block Or Does He Need To Look For Parts That Are Specific. Or Can He Some How Mill The Top Of The Block Down To Make It A Standard Block.
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05-20-2005 #2
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Get the casting numbers, and look them up on www.mortec.com.
If it's a tall deck, I'd pass on it an look for a standard deck. They're still pretty easy to find. Less problems with intake fitment, headers, hood clearance, etc.
05-20-2005 #3
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Your friend most likely has a standard deck 454. Legend has it that some tall deck 454's exist but I've never seen or heard of one,,yet.
If that engine is a 427,it very well could be a tall deck.
I agree with Mark's suggestion.
05-20-2005 #4
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A standard deck block has a deck height of 9.800" while a tall deck is 10.200" If you have the clearance underhood and are willing to order tall deck specific intake manifold and headers, this combination has a +.400" longer connecting rod. 6.535" as opposed to 6.135". Improving rod to stroke is desirable on a big block. So tall decks are good things, just specify "tall deck" when ordering parts.
-Heads are the same (just moved up and out)
-Intake is different (or you can add spacers to a 9.800" intake)
-Headers may vary (std headers may or may not fit).
Hood clearance can be a concern.
First thing to do is measure distance from the crank centerline to the deck. It's not the easiest measurement to take. Also the block may be marked "truck". The block may have been "decked" over the years so don't be surprised if you can't come up with exactly 10.200" Confirm what you have before you buy any parts. As Clint said, many moons have passed since GM put tall decks in trucks (early 70's??), so there's a good chance that you have a standard deck block.________________
Steve Chryssos
05-20-2005 #5
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tall decks
the tall decks used in large trucks are .400 taller so gm could get another ring pack on the piston. the cd on the piston is where they made up the .400.
rods are usually the better 'truck' rods(stronger).
these were only available in 366 and 427, there were no 454 tall blocks.
about the only parts i would use from these would be the rods and crank.(same stroke as 396 and 427 low deck)
the heads will bump compression on a stock 454 about 1 point, but they should have some bowl work done on them.
dont use later 'peanut port' heads.
doug
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