Head Questions...
Thread Starter
Melting Slicks
Joined: Jan 2006
Posts: 2,664
Likes: 1
From: Nashville TN
Head Questions...
I have a 72 with the base motor. My heads are 3973487X. On the breakdown to what I have it lists the 76cc and has 10cc to add or subtract from the 76? Im not sure what is means if the X heads are better or worse than the other ones?
It reads:
3973487X 350 68-73 1.94/1.50 2.02/1.60 76cc X cast 10cc's
It also lists the same valve sizes as the double hump heads (186 casting) that my uncle gave me when I first purchased the car. The double hump heads are 64cc? I can build a motor if someone puts the stuff in front of me but I have no knowlege of how to match things and how to read what the tech stuff is talking about.
Question one- what heads with the X casting do I have and are they better or worse than the other base heads without the X on the end?
Question two- I am keeping the original stuff with the car and the matching numbers block but I was thinking of using my uncles heads he gave me (186 double hump) for more performance. Are the ones that came stock on my 72 with the X casting just the same as the double humps I have?
Thanks for any help you can offer...
It reads:
3973487X 350 68-73 1.94/1.50 2.02/1.60 76cc X cast 10cc's
It also lists the same valve sizes as the double hump heads (186 casting) that my uncle gave me when I first purchased the car. The double hump heads are 64cc? I can build a motor if someone puts the stuff in front of me but I have no knowlege of how to match things and how to read what the tech stuff is talking about.
Question one- what heads with the X casting do I have and are they better or worse than the other base heads without the X on the end?
Question two- I am keeping the original stuff with the car and the matching numbers block but I was thinking of using my uncles heads he gave me (186 double hump) for more performance. Are the ones that came stock on my 72 with the X casting just the same as the double humps I have?
Thanks for any help you can offer...
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
i have a 72 with the same motor and the same heads. The X heads are better as they have bigger intake ports and most of them have bigger valves...these were the same heads that Lt-1s got in 72 stock but some base motor cars got em also for some reason. I would go with your uncles double hump heads though, much better.
Racer
Joined: Jul 2005
Posts: 317
Likes: 0
From: PA
yes the 64's will raise the compression but they will not out flow most of the larger chamber heads. it all depends on what you want to do with the motor, if it's a mild streeter, you'll never tell the difference.
