DodgeCoronet.com

Got a short deck big block on the stand. It came out of a 71 Challenger R/T, original to the car. Build date on the block is 6/71. Stampings on the pad are unreadable because of the heavy orange paint.

Pistons are L2315F .060 over. Those are for a .060 over 383, which makes the bore 4.310. Checked the bore, and it's correct.

Has a forged crank in it. Stroke comes out to 3.38, so it appears to be a .060 over 383.

Here's where the fun comes in.

Casting number is 3614230-5, which is for a 400 block. Block has the stiffening ribs for a 400, and the thick main web supports of a 400. Even has the different bellhousing patter for a 400. So for all intents and purposes, it's a 400 block. But the cylinders are bored for 383, and there is no sign of any sleeving being done.

Did Chrysler start casting 400 blocks and only boring them to 383 specs late in the 71 model year?

That's interesting.

It might be a question for a larger audience.

What's the bore of a 400? And are the walls thick enough to be bored out that far?

The block was decked so the numbers on the pad are gone unfortunately.. Casting date is June 7, 1971 1pm Day shift. Only other casting number is 2X below the head on the right front.

Everything points to a 400 block (casting number, stiffening ribs, raised hump on bellhousing mount), and everything points to a "cold weather block" (casting date and thick main webs). Can't use the heads as a reference, as those disasters are late 78 castings.

Another strange thing is no VIN stamping on the pad. Not even a hint of it under the paint (it was brushed on it appears).

"Stampings on the pad are unreadable because of the heavy orange paint". get that paint off there and take a look I won't tell Galen I promise

Could it be an industrial motor of maybe a warranty block?

Industrial/Warranty would explain the missing VIN stamping, but not the fact it's a 400 casting with a 383 bore.

It's definitely a strange one..

...put some heads on it and run it!

theman440 Wrote:...put some heads on it and run it!

Oh I plan on it..

Max will be wimpering in the corner soon... wishing Daddy never took him out of the carport...

Max doesn't know how to whimper. lol

Tried flipping it over and seeing the engine serial number had to say, but no dice. Nothing was ever stamped there..