Hey everyone. How do I tell what year my engine was manufactured? The code on the block reads 203A13. The reason I need to figure out the year of the engine is this...
I got 3 different valve covers here, ranging from $25 to $180. None of them will fit on my head without hitting the rocker bridges. They all fit great. but the baffles-none are the same as stock. They are all flatter and wider than stock, and don't fit between rockers. Jeep has been down 2 weeks now over a leaky gasket. Anyone happen to have a pic of inside a clifford cover for a 78 cj7 258? I'm about to put my crash helmet on and flip it down through the field, collect insurance check and start over! Probably less down time! <img src="/forums/images/graemlins/lol.gif" alt="" /> Of coarse, can't order it even if it is right until I get my 200+ bones back for all the other covers. I can't be the only one out there whos had this problem. Please help.

Darlin it ain't the block that is giving you problems! It is the HEAD. Past owners may have installed a different year model head. Look up the head numbers.
The early heads had covers that were attached thru the cover top and into the bridges on the rockers.
You just MAY have an early head that takes a TIN cover.
Look at the gasket surface on the head itself and see what the shape of the gasket HAS TO BE. Then go to the parts house and look at the various gaskets they have to offer for ALL YEARS.. get the one (ones) you think might fit and take em to the head.. The one that fits is the year cover you need.
Jeep did not do us any favors with all the damn head covers they made.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

Gonna go look for numbers. But the gaskets i've gotten have fit the head perfect. These 3 covers fit the head perfect. Its the baffles inside.

Ok then maybe you have some not stock rockers? Is there a bridge on the rockers with a bolt hole on the top? And is this part the part that is affecting the baffels? If so can you take the bridge OFF without affecting the function of the rockers themselves?
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

O.K. got the head clean, only #'s i found were these...
In between the rockers where the stock baffles fit in between, front one reads 76. Backside(same spot) reads HN, below is a D stamped on the head itself. Does this tell us anything? I'd assume this is the head off a '76, but we all know what happens when we assume! Even still these covers should fit '72-80 cj's.

There are very small holes in the top of the bridges, but no bolts in them. The not stock bridges would make sense. The 1/2" or so for cover to meet the head is about the same distance that the bridges stick up away from the rocker arm. I know for sure the bridges and pivots were replaced right before i bought it. How would i see if i can take them off without damaginganything?(bridges)

Are the small holes threaded? Do these bridges do ANYTHING?
Can the bridges be taken out without changing anything in the rocker geometry? If the bridges are inert... I'd throw them away and use the covers you already have.
OR if the bridges need shortening and then replaced I'd consider a sawzall..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

The holes are not threaded. There is nothing else bolted to them. The bolts go through the bridges, through pivots, and down through arms and into the head. I'm thinking just take them out. Wouldn't the pivot and bolt keep pushrods and rocker arms doing what they're supposed to? I went to the only parts store around that had some bridges in stock, and they were the same dimensions as the ones i have on there. So, i'd vote get rid of them, right?
Big Jim, i'm gonna have to send you a housewarming gift for this! <img src="/forums/images/graemlins/lol.gif" alt="" />

You have described just what I remembered. Throw the suckers out!
I prefer redheads..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Unless IÆm mistaken, the purpose of the bridges (besides the ones that hold down the cover on mine) is to insure alignment of the rocker arms. If you take them out be darn careful not to misalign the rockers when tightening the bolts. They are not there just to be aggravating!

To answer the original question, here is a link to a page that explains AMC engine build date codes.
web page <img src="/forums/images/graemlins/cheers.gif" alt="" />