LS7 Fuel Rail Covers on LS3\L99

[Eddymel1998]

Okay so say theoretically I want to put a set of ls7 fuel rail covers on my L99 engine, theoretically all the mounting things should line up more of less, except for one major one, the engine oil cap since ls7 came with the dry sump. So options are either go to town with the Dremel and make a hole GM wasn't brave enough to make, or shorten the oil cap spigot somehow.


This is where I need help, I noticed that aftermarket valve covers have just a cap bolted straight into the valve cover, is there a low profile option like that but for stock valve covers? I did find part number 12589431 which is a shorter neck GM uses on the 2.4L engines, mounting looks the same just eyeballing it but does anyone know if it would work?

[Eddymel1998]

Just to follow up on this in case someone finds this searching for same thing. It can be done and here is the pic of it mounted


Few tips and tricks for anyone else looking at trying this:


-you will need 4 studs to mount the cover, my l99 came with one already, PN is 11609319, they will mount in existing holes on valve covers

-you will need to replace:
---dipstick, the stock one is too tall, you could probably cut down stock one, I went with one from Jegs (555-52252) it was alright but not huge fan, gets the job done though
---oil fill neck and cap, since ls7 is dry sump it does not have one of these, biggest issue here are the locking lugs, the cap has channel for only one, the valve covers have two so most aftermarket caps do not work, you can create your own grove with a Dremel or something similar on an existing one lug cap but I just went with a Holley (241-224) one that bolts straight into the 2 lug valve covers
---PCV hard-line coming from back of the driver side valve cover to right behind the throttle, this one runs along fuel rail and gets in way of the cover mounting feet, I bought the cheapest GM PCV Hose with same looking fittings (in my case it was a Corvette one, PN 12608307) then cut down the ends and used 3\8 inch inner diameter fuel line hose with some hose clamps, you can also just cut your existing pipe but I didn't want to risk it
---Heater hose relocation (if it's early 5th gen with the heater hose on top of engine), for this one just grab a heater hose from a 2012 and up Camaro (I got a dorman one for half the OEM price and it seemed good) then follow one of dozen guides on this forum, I used this one because of the pictures: https://www.camaro5.com/forums/showthread.php?t=183191


-when you finally go to mount the covers install the studs FIRST, then work the cover on and cut off bits that don't clear, I've had most of my problems on plenum side, I also started by clamping it to the fuel rails and putting it on bolts second and overcut by a large amount, in end I cut off maybe 2-3" from the plenum side and some in passenger front (I was trying to avoid heater hose relocation but did it later anyways so hole remained), expect to cut about an inch of so of material if you do it properly.



That's about it, I also broke one of the clamps on passenger side cover so take it easy and make sure they don't get caught on the rat's nest of wires and lines around the fuel rails, these are also on my 2010 SS with L99 in it so some of this might be different.