383 Engine ID Pad --clean as a whistle

[Hemi 354]

Hi everyone,

I picked up a 66 Belvedere with a 68 year 383. Highly modified, but the engine ID pad near the distributor is C-L-E-A-N. Nothing there! It's a 68 block, verified by the casting number and date stamp.

What would cause this? Block decked? Just curious as I have never had one like this.

Thanks

 

[69a100]

What would cause this? Block decked? Just curious as I have never had one like this.

Thanks

^^^^This!^^^^^^^^

 

[Cranky]

Any machine marks on the pad or is it good and smooth?

 

[dieseldazzle]

Decking it can do this

 

[oldbee]

Yeah but how much decking? Wow.

 

[Cranky]

Yeah but how much decking? Wow.

Only one way to find out but it doesn't take but about .010 to clean off the pad on 'B' engines.....

 

[Paul Boucher]

Please excuse my ignorance, but what is decking an engine? Machining? And if so, why would you need to machine the stamp pad?

 

[69L48Z27]

The pad on a 383 is over on the right bank and part of the deck plane. A fly cut on the deck surface would clean the pad off. They are not up where a 440 would be. That would be pretty hard to screw up.

 

[Cranky]

Please excuse my ignorance, but what is decking an engine? Machining? And if so, why would you need to machine the stamp pad?

Yes, machining the head gasket surface of the block. Sometimes a very light cut is taken just to clean it up for a fresh surface but some deck them quite a bit.....and like 69L says, the pad on the B engines is on the same place as the deck surface.

 

[Paul Boucher]

Thanks guys! Makes sense now. Never heard the term "deck plane", but I know now. I have a 383 and will take a look at the plane surface lines in the morning before I head to work.

 

[Mopars & Missiles]

A couple photos to illustrate the process. The cutting head used for decking a block is about 12" in diameter & if it is allowed to travel the full length of the deck on the passenger side of the engine, it WILL wipe out the stampings on the "B" engine pad. Below we used a cardboard cutout to simulate the size of the cutter and make a mark on the block where we wanted to stop the cutter to preserve the original engine stampings but ensure that we still decked far enough to clear the cylinder head when assembled.

 

[Cranky]

Thanks guys! Makes sense now. Never heard the term "deck plane", but I know now. I have a 383 and will take a look at the plane surface lines in the morning before I head to work.

I've heard people say "plane the block" but in my world, planing is usually a wood working term and not machinist lingo. If the deck isn't square to the crankshaft center line, that's another reason to deck the surface. Some say .005 is about max out of square but sometimes a rod or a piston won't be on the money (varying .003+ isn't all that uncommon) but if you do have a rod/piston combo that's longer or shorter, you can play games and use a block that's not exactly square. So long as the main bores are true and straight, I'll play that game especially if the deck is in great shape already.

 

[Hemi 354]

The ID pad in question is clean, no machine marks.

 

[PurpleBeeper]

I "guess" another possibility might be a dealer replacement block????? I'm not sure about that, but I've heard that dealer replacement blocks don't have all the numbers that OEM blocks do. Don't quote me on this though.