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ZL1 lid milling

18K views 35 replies 23 participants last post by  RapidRob 
#1 ·
If any of you guys are on the fence about installing a Zl1 lid, but don't want to mess with cutting the hood I am offering a milling service. I can also drill the factory fittings out and tap for 1/2" NPT. That way you can use an adapter and run -10 or -12 AN fittings.

The price is $75 + shipping for the milling
$10 extra if you want it drilled and tapped
 

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#19 · (Edited)
the blur said:
How much are you milling off ? Does it completely clear the hood ?
I'm touching off my tool at the yellow dot (top of first rib) and milling down about .260 from there. After I mill the first 2 ribs and the pad they run through I'm coming up .040 for each remaining rib to create a taper effect. There are no clearance issues with the back of the lid. It's only the first two ribs and pad that are the issue. I've done a little over 20 lids and everyone has cleared the hood with ease. I have had 2 where the very front of the lid just kissed the hood liner. Basically the very front edge of the flange where the hoses mount. Not even enough to leave a mark on the liner. If you feel behind the liner where it is touching there is still plenty of clearance before you get to the hood. One person just left it as is and the other cut a little window in his liner. I'm taking them down as far as I feel comfortable doing so. I don't want to put the integrity of the casting at risk. If you have any questions please feel free to call or text. I'd be glad to answer any questions or address any concerns you may have. Chris 214-549-0357
 

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#21 ·
the blur said:
So technically, you can mill the 1st 2 ribs, and the pad area, and leave the remaining cooling fins ?? Did you ever consider that ?
One of the first lids I did was like that per the owners request. He hated the way it looked so he had me mill them all down. Later on down the road a customer requested a taper. It looked the best in my opinion and from that point on everybody has requested the taper. I can do it however you want it. My opinion is the heat sinks are more cosmetic than anything. It would be one thing if you had cool air moving across the top of them but you don't. The factory lid has zero heat sinks with a smaller intercooler.
 
#23 ·
Trapspeed said:
Love the tapered look myself. If I ever do this mod I'll have it done.
Thanks man. Sadly as many lids as I've done I haven't had time to mill my own. But when I do I'm gonna do the taper as well. This started out as just helping a guy out and it turned into about 6 lids a week. Between this and being a full time machinist time is limited.
 
#27 ·
irishc6 said:
If any of you guys are on the fence about installing a Zl1 lid, but don't want to mess with cutting the hood I am offering a milling service. I can also drill the factory fittings out and tap for 1/2" NPT. That way you can use an adapter and run -10 or -12 AN fittings. The price is $75 + shipping for the milling $10 extra if you want it drilled and tapped
I can also drill the factory fittings out and tap for 1/2" NPT. That way you can use an adapter and run -10 or -12 AN fittings.

Forgive me for asking but I'm clueless on this and and want to know what does the drill and tap of the factory fillings out do. Please go into detail on what this for that supposedly making it better rather than leaving the factory stock fittings on there as is?
 
#28 ·
Drilling out the fittings and installing weld in bungs or threaded inserts opens up the inside diameter of the fitting letting more flow in to the brick. On mine the difference between the pressed in fitting and the drilled and tapped was significant, like almost a 1/4 inch. I'm running -12AN with 3/4" hose.
 
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