I got the info below from Mortec but it doesn't tell me a whole lot. Does anyone have any more info?

3973487....71-72...350..........used on 71-72 350 LT1, 75cc chamber
3973487X...71-72...350..........75cc chamber

Thanks

 

Don't hold me to this, but I thought the X heads intake port was about 10cc larger.

 

I dont think theres any difference at all. I think the X just denotes that the head originally came on a corvette. Whereas the plain number was probably camaro.

 

I've rebuilt engines with 487 and 487x heads. Both numbers I've seen came off 4 barrel-350s out of '71-'72 full size cars. Nothing special about the engines. However, I do remember reading, a long time ago, that the 487x was just slightly better flowing.
jms

 

I have a pair of the 487X's in my back yard ready for the 'Junk Yard'. Are they worth keeping?

Let me go on a bit. I've already built a 383 with A/M heads (Dart IE 200/72). A friend of mine is now building a 383, and I believe there is a little 'Monkey See- Monkey Do', but I spent some time at his garage the other day and dammed if he isn't going with a nice looking re-built set of 487X heads with Stainless Valves, etc.

Does that make sence? (See also my first statement)?

 

It's possible that Jihn is correct, I recall the 461 and 461x castings of the mid 60's, and the "x" casting has larger intake ports.

Sorry, I've not heard of the 487's, but a trip to mortec.com or chevymania.com may yeild some info.

 

Thx for the lead on www.ChevyMania.com, here is what they say:

3973487 68-79 1.94/1.50 & 2.02/1.6 165-330 76 CC Chambers
3973487X casting has 10cc more intake volume.

Starting from a well weathered bare casting are they worth resurrecting, from the dead?

My intentions would be to use them on a budget 383 build. I already have a spare #010 4-Bolt ready to go, bored, decked and notched.