Pistons on a 77 440

[MagnumForce]

I just cleaned the tops of the pistons on a 77 440 and i found 03 engraved on it. I was told it it meant the engine was bored .30 over and if that is the case i cant imagine why the pistons are still .15/inch below deck? Why would someone go through the trouble of boring an engine just to put more low compression pistons in, especially since the original owner was supposed to be a serious hot rodder and it was in a 69 roadrunner in the 80's. Has someone else had a similar experience or was the builder of my engine just severely misinformed. 

[Cooter]

I've pulled down 440's with 7 Six Pack rods and one 'LY' rod. I've seen rebuilds pistons used being 'advertised' as "10.5:1" pistons,  I've seen a 78 440 with cast crank balancer and torque converter, but have a steel crank that Mallory metal had been welded in to rebalance to external balance. Most times the piston will be stamped ".030" not 03. Need a picture.

[BSB67]

Unfortunately, it is actually quite common.  Sealed Power/Speed Pro/TRW were some of the only pistons available for a lot of years for the average guy.  Combine this with people being uninformed and on a tight budget, and the 1.99" and 1.91" compression height piston became common in rebuilds.  They are still the least expensive pistons out there today.  The 1.99" piston use to be advertised as a 10:1 CR piston, and replacement for 1967 through 1971 440s, but in the fine print you could read that it required a blueprinted 915 head.  You have the 1.91" piston.

They stopped making the original replacement piston for the 1968-1969 440 back in the late 1990s. That left for the typical street guy the 6-pack piston, which, of course, is a good choice, but for some reason, seldom chosen.

When a guy is contemplating the purchase of a good deal on a rebuilt 440, it almost always has one of these two pistons in it. I always plead with the potential buyer to not purchase these engines.  FWIW, these engines usually also come with a junk set of heads with a recent valve grind, also represented as rebuilt.  There is no real good way of fixing this kind of a engine rebuild without throwing a bunch of money at them.

[MagnumForce]

The 0 is barely visible

[Challenger340]

Yessiree..
just as BSB67 has already mentioned, this is a very common mistake/problem that has occurred thousands of times over the decades with rebuilt 440's.
D-Nutted 440's !

Just lack of knowledge, and bad/in-accurate Piston Catalogs used by rebuilders
because....
I just can not see anyone actually TRYING to make a 7.8:1 Compression Engine on purpose ? when rebuilding ?

[Cooter]

Swap in a seg of Six Pack pistons, but don't run em with closed chamber heads and steel shim gaskets....

[MagnumForce]

So the pistons definitely were replaced and the cylinder was bored?  Ill see about getting the pistons at a local swap meet coming up. The good news is that my 452 heads seem to be ok but im going to have my friend check them out to be sure. Thanks guys