L99 AFM/DOD Options

[ZSH]

Hi all,

First post here, and I have done a lot of research thus far. I purchased an L99 Engine and 6l80 ( I think) transmission with 31k miles on it to put in my 1967 C10 SWB. I've read a lot about the LS3 conversion kits but its a lot of money to fork out for lifters, cam, etc etc - we all know the parts already. I don't want to have to worry about the weak lifter concerns that the L99 motors bring into the picture. So here's my options, and please let me know if I have other options (NOT LOOKING for "Buy LS3" comments please). I just want stock HP or a little more, with better reliability.


1. Replace AFM lifters with new ones and just use Range AFM Disabler, Diablo Tuner, or HPtuners (some sort of tuning device)? If I did this, is there a fix for weak AFM lifters versus just replacing with OEM lifters?

2. LS3 Conversion Kit that seems to be within the $1400 range for all parts unless you guys can point me in a direction that would cost less than that.

Again, I've read so much out there and I am just trying to figure out the best route. I don't like the AFM/DOD, and I want the motor to be reliable. The motor is on a stand right now so I pretty much have free reign to do what I please with it without spending countless hours removing whatever. I do have a budget though, so that's why I didn't want to spend the $1400+ on the LS3 conversion kit.

Thanks,
ZSH

[InFiD3ViL]

If you want it reliable you really need to get those AFM lifters out of there. They can fail even if disabled in the tune. Some people can get 200k+ miles on them, some have them fail with less than 50k miles. My AFM lifters lasted through 153k miles without any problems. When my L99 did fail, it was not related to the lifters at all. The problem is you never know when it's going to happen and once it does it gets very expensive.

You can save some money, do the LS3 conversion, and just buy a used LS3 or LS9 cam. Lots of them around and you will get a little bit of increase in lift over the stock L99 cam. You can probably pick one up for $100 and you can still run the stock springs also.

The way I see it is that the engine is currently out of the car and easily accessible. Now is the time to replace anything that would turn into a huge project once installed. If this was my build I would definitely not install new AFM lifters.

[ZSH]

@InFiD3ViL, So I am fine doing the work to do the LS3 Conversion but how much would it cost total + the cam? There are so many shops out there offering different kits. I like the GPI kit for afm/dod delete from:

https://gwatneyperformance.com/produ...trays-included

I would get the 4 lifter trays, Chain Dampener, Timing cover gaskets, timing cover seal, water pump gaskets, set of 8 or 16 Chevrolet performance hydraulic roller lifters (not sure if I should replace all or just 8), ARP Headbolts kit, crank bolt, and do I need oil block off set of 8? under 11. Valley Cover/oil blockoffs?

I could get all of that for $471.66 (8 new lifters), or around $602 for 16 new lifters.

Then I would just need a LS3/LS9 Camshaft?

[pyroguy]

Eliminate the AFM/DOD lifters and do an AFM/DOD delete install. IF you want, you can do a VVT delete as well and do the full LS3 conversion. The decision to switch is hotly debated on the forums as VVT will yield more low end torque, but the LS3 conversion will yield more high end horsepower. When I was looking at my cam swap I had two highly reputable shops recommend a LS3 conversion primarily because they said the gains of VVT was minimal and it was another thing to potentially go wrong.

[InFiD3ViL]

The new valley cover should come with the oil tower block offs/o-rings. If it was mine I would do all 16 lifters, but seeing as you are low miles on that engine you could probably get away with 8, as long as the original 8 are in good condition.

Since your L99 is also a VVT engine, you would also need to either convert it to non-VVT as well, or replace it with another VVT cam (more expensive option). The conversion to non VVT is not expensive, as all it requires is a new LS3 front timing cover and a $20 harness that TSP and some other sites sell to convert the 5 pin L99 cam position sensor harness to an LS3 3 pin connector - and a non AFM VVT cam. I am not sure if the upper timing gear would need to be replaced if deleting VVT, as both the OEM LS3 and L99 use a 1 bolt timing gear. I may be forgetting a couple of things, but I don't think so.

Sorry, I forgot about VVT in my original post - but deleting VVT is not nearly as costly as deleting AFM. Also, they do sell kits to do both a VVT and AFM delete. Lucky for you this is a question a TON of other L99 owners have had to face, so there is a ton of info out there on this. I would say take your time and consider the best option for you and your wallet.

[ZSH]

Okay you guys have talked me into it. Who knows the best place to purchase these items for the cheapest? I see a good amount of places are out of stock on some of the kits. So once I install the DOD/AFM delete and VVT Delete Kits, and install an LS9 camshaft, will I have to do anything else? I don't have to change springs/valves for the ls9 camshaft right? What about piston clearances too? Has anyone done this?

[ZSH]

Just looked at my local facebook marketplace and getting LS9 Cam for $100, BTR 3 bolt conversion kit for $25, and timing cover and gasket set for $40. I think I'm on my way LOL