Anyone swap a 366 or 427 tall deck?

[dsteelejr]

I'm considering dropping in a tall deck 366 or 427 into my K25 when the time comes to replace the 454. Information about tall decks is relatively scarce compared to standard SBCs and BBCs, but I did find some valuable info on what modifications would be needed and they are only minor. I am also aware of the intended purpose of the medium duty tall deck engines: toque for low end grunt work, not speed, which is fine by me because my K25 is a work horse, not a speed demon. A lot of people toss the stock tall decks aside because they say they are sluggish boat anchors, but I've also heard they are fantastic if you use them in the intended power range, which is low end torque. Has anyone successfully put a stock (not modded for performance) tall deck 366 or 427 into their square? Were you happy with the results? Pro? Cons?

 

[Shorty81]

I haven't, but very interested in hearing more. We had tall decks in grain trucks. I think would make a great motor.

 

[dsteelejr]

I haven't, but very interested in hearing more. We had tall decks in grain trucks. I think would make a great motor.

Most people either hate these engines because they are boat anchors or hot rod engine builders love them (at least the bare block) because they can easily stroke them out. Tall decks are 0.4 inches taller than the standard BBC (9.8 inches vs 10.2 inches). This is because they put a third compression ring on the pistons and the taller deck accommodates the taller piston without changing the rod length or stroke. Engine builders take out the tall pistons and put regular ones in and use the extra deck height to stroke it out. Also, the tall decks are all four bolt mains, which everyone loves. Thats beyond my skills as a home mechanic. I just want a high torque engine without having to convert to diesel or other major mods.

If you're interested, for further reading check out this site. This is best info I found so far on the subject.

https://www.tradecraftspecialties.com/bbckb

Opinion piece "Why bother with a 366?"
https://www.tradecraftspecialties.com/bbckb#Topic7

Opinion piece "366/427 versus 454"
https://www.tradecraftspecialties.com/bbckb#Topic12