I should never say never, maybe marine had a 454 tall deck in those days but the medium duty trucks certainly never did.

You can make nice 489 out of a tall deck 427 block. I used to swear that Chevy never made a tall deck 454 truck block but as I understand it they did very briefly in the mid-80s. I have been searching for proof but coming up empty. I did at one point see a mid-80s Chevrolet medium duty brochure that clearly showed the 454 as being available in CE70 & ME70 trucks. I was surprised by it. They weren't popular & were dropped, while the 366 & 427 continued.

A tall deck 454 would have been for marine use, like Mercruiser. Marine engines can have 2 caveats. 1 is that salted water jackets & galvanic corrosion can destroy them. 2 is that every run with a marine engine is a dyno pull.

If the jackets are clean & the block isn't shifted, it might make a nice seasoned block for a rebuild. Most people are shy of marine blocks though, but in so doing they unwittingly turn up their noses on engines like a super rare 427 Ford FE that used to be used in big Chris Crafts.

seventy2plus2 wrote:

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4SPEED427 wrote:

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A 1970 454 can't be a tall deck. They only started the tall deck 454's in the trucks around 1980 (I forget the exact year). I'm thinking it's a 427 tall deck?

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 Was the 427 truck engine externally balanced?  This definitely has the counterweight in the flexplate.

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 I don't think so because guys put 427 truck cranks into 454 short deck blocks and make 427's that way.

Sure looks like you kicked a hornets nest over there Carl, Randy would be proud.

Code

Year

CID

HP

Trans

Platform/CommentsNo

AUA	1979	454	245	MT	L42, 70
AUB	1979	454	245	MT	L42, 70

4SPEED427 wrote:

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Well cool, that's for the C70's I take it by looking at the "L42,70" ?

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 CORRECT. 
FOUND THAT ON A SITE CALLED CHEVELLESTUFF.NET.

http://chevellestuff.net/qd/engine/bb1_codes_aaa_awr.htm

-- Edited by 68 427 on Tuesday 3rd of October 2023 04:15:57 PM

I took another look today, and found some conflicting information. 

Attached are photo's of the counterweight on the back of the flexplate (454 automatic), and also of a pilot bushing in the back of the crankshaft (manual transmission).   I also took a look at what I could see of the back of the harmonic balancer, and didn't see any counterweights.   

So, I believe this is a 1970 427 tall deck truck block that originally had a manual transmission behind it.  At some point, the manual transmission was removed, and a 454 (or 400 small block, both are externally balanced) flexplate was installed on it.   Back to my original question, is there any value here?

seventy2plus2 wrote:

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4SPEED427 wrote:

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A 1970 454 can't be a tall deck. They only started the tall deck 454's in the trucks around 1980 (I forget the exact year). I'm thinking it's a 427 tall deck?

---

 Was the 427 truck engine externally balanced?  This definitely has the counterweight in the flexplate.

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 A 427 is internally balanced, 454 externally. If it has a 454 flexplate, the balancer will have to be for a 454, (big counter weight on the inside)

I would say "little value" except for someone looking for a tall deck 427.  Why would they go to all that work, when 454's are more common and the parts are easier to obtain....

My .02 cents

-- Edited by LT1Caddy on Tuesday 3rd of October 2023 08:37:15 PM

4SPEED427 wrote:

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A 1970 454 can't be a tall deck. They only started the tall deck 454's in the trucks around 1980 (I forget the exact year). I'm thinking it's a 427 tall deck?

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 Tall deck 366s started with the 1966 C60 & C80 (when Mediums were 50, 60, 80 series), the tall deck 427 started with the 1968 CE60 & ME60 (when Mediums were 40, 50 , 60 series).

 

Carl, you are right that the tall deck 454s didn't come out until much later (1979 apparently).

 

Medium/HD truck engines have forged cranks, 4-bolt mains, low compression, oval port heads, mild cam timing. They are designed to use regular gas and not complain while under full throttle & low r.p.m.

 

My brother for work drove a brand new '79 Chevy CE60 Scottsdale with a 366 & an Allison automatic. It was a furniture van.

-- Edited by CdnGMfan on Thursday 5th of October 2023 05:09:35 AM

I finally found a picture of a heavy truck 454 and it doesnt appear to be a tall deck, but does have the big truck water pump and dual thermostat housing.

yet another visit today to the tall deck.  While we've established it's a 427 tall deck, the crank was in question.  

I'd previously determined the balancer / 4 groove pulley were 1 unit, but wasn't sure how to remove them.   The block is in the back of a pickup along with 2 other blocks, a complete front suspension from something, a transmission & a rear bumper.  Access isn't very good.

I could see 1 bolt hole for a remover to mount to, but a poor angle prevented me from seeing anything else.   I was able to get my camera down there to see this on the balancer face:

I figured the holes generally at 12 & 6 o'clock would accept 3/8" bolts from my puller.  (Carl warned me they may be fine thread, which I didn't have).

I flipped the block upright (with it resting on the rear bumper in the box of the truck), with the balancer pointing straight up and forced my 4" 3/8" course thread bolts into those holes.  The balancer put up a fight, but it eventually came off.  Thank God.

Once the balancer was off, next was the timing cover.  With it off, I flopped the block back into the truck block, with the oil pan up.   Off it came to reveal the inner workings.

I couldn't see any casting marks, so measured all of the counterweights, they're all 3/4".   Counterweights on 427 cranks should be 7/8".

In a attempt to see anything else, off came the main caps, but they didn't reveal any casting numbers, etc.

I left the main caps, but might go back and grab them.

I got most of the nuts off the connecting rods, there's a couple that I couldn't get, but with a little perseverance I think they could be removed.  Then a little tinkering to get the rod caps off for crank removal.

So, after all this, it appears to be a 396 crank in a 427 tall deck block.  The only thing I was really able to salvage from it was a 69 auto big block water pump that can be used as a core.