CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

L18 8.1L swap resource thread

I am once again a member of the 8.1 owners club! I picked up what appears to be a 2003 with a claimed 30k miles from a
Schwan's truck. While reading one of ktmoutfront's build threads he mentioned having an 8.1 and I knew he had a cross country move coming up so me being the kind guy that I am I offered to take it off of his hands to lighten the load while moving. After some thought he got back to me with a price and the rest is history. It is missing the injectors and fuel rails so I am on the hunt for those.
I really got to get better at taking pictures.

View attachment 302150

View attachment 302151

View attachment 302152

View attachment 302154

View attachment 302155
I have a return style fuel rail with injectors if your interested.
 
So after reading this thread about 5 more times and Larry's other threads again I have figured a few things out.
It appears this engine has already had the top radiator hose housing from a Silverado installed. I also noticed masking tape under the intake manifold gaskets so it will be coming off to figure out what is going on there. @Larry also mentioned that the ZF power steering pump is just to big for a square chassis without hacking the frame and after looking at my L29 sitting in my K5 it appears the ZF fittings if not the actual housing will not clear. So that will have to be addressed.
{All together now say it out loud.... "Don't be that guy who hacks a frame"}
In the box of parts I received with the 8.1 there was a windage tray and some other tins I am not sure are even for this engine or maybe something else??
I have purchased the return style fuel rails and injectors from Rick Capito but the list of parts I still have to source is growing.
I am still not sure what project this engine is going in but it will either be my CC avatar or my 67/69 SWB.

IMG_20190509_135847972[1].jpg

IMG_20190509_140054061[1].jpg

IMG_20190509_130143625[1].jpg
 
Last edited:
Thought I'd post up some Pic's of my 8.1 install in my 77 k10/30, many thanks to Larry for his article and sharing of his knowledge on the subject.

Wow, that looks great! Very sanitary job! I really like your airhorn on the throttle body and those battery cable ends…..well, actually, everything! I like it all. Does the airhorn rub the hood at all? The one on my Suburban rubs the hood badly but the same part number fits my K10 with the flat hood just fine. I also need to get some battery cables like those for the blue truck. Very nice job!
 
Wow, that looks great! Very sanitary job! I really like your airhorn on the throttle body and those battery cable ends…..well, actually, everything! I like it all. Does the airhorn rub the hood at all? The one on my Suburban rubs the hood badly but the same part number fits my K10 with the flat hood just fine. I also need to get some battery cables like those for the blue truck. Very nice job!
Thanks Larry, This whole thing is because of your article here and I couldn't be happier. I trimmed the throttle body end of the air horn about 3/8" so it just clears the linkage cam that lowered it about 1/2" the battery cable ends are the military style and I found the boots on eBay. Thanks Again for all the info it saved a lot of time and money.



.
 
I know a few of you fallow this guy on Instagram but I figured I'd share this over here for the giys that don't in case it wasn't already. They're made to order for $350 since the workhorse brackets can be scarce at times

Screenshot_20190601-092643.png

Screenshot_20190601-092635.png

Screenshot_20190601-092619.png
 
For anyone reading my K5 thread, you know I am going to start an 8.1 swap this fall/winter. I've gotten a few pages read, but will be sitting down this weekend to read it all over and take some notes.

Thanks to everyone who has posted to this thread sharing any and all info. Because of this thread, I have more confidence in myself to knock this out. So thank you guys!!!

This is my current setup. Lots of little parts to gather still. Engine was originally from a 2005 with 106k miles on it.

c944d269-0daa-4095-a93f-2fef1b83eb61-jpeg.310364
 
Gonna do that intake modification I've been hearing or reading about?
 
Are you talking about removing the baffle inside the intake manifold?
 
Are you talking about removing the baffle inside the intake manifold?
I think that's what it was called and done. It's been a while since I read up on it but that does sound familiar.
 
It requires cutting the bottom part of the intake off, then with a grinder removing some restrictive baffles, then you have to weld it back together. However it's aluminum, so you have to have an aluminum welding spool gun to be able to do it. My brother did the mod himself on the 8.1 we're putting in our 4 seat buggy we're building. That 8.1 got a rebuild with a different ring gap, raylar cam, intake mod, and will eventually get a turbo (hence the different ring cap to handle the boost). We're gonna run pretty low boost, probably 5 lbs or less (mainly cause we didn't want to spend the big bucks on forged bottom end, so if we keep the boost real low it'll still produce good power without destroying the bottom end). We still think we can get close to upper 500's on hp and close to 600 tq when it's all said and done, but should still idle real well so it can still be trail wheeled rather comfortably.

First two pics below are of the welded up portions of the intake after the mod (sorry, I don't have any pics of it opened up on my phone)...last pic is my brother putting the intake in his bath tube to check for leaks in the welds :haha:

1.jpg

2.jpg

3.jpg
 
if someone wants to read through this. got p/n in there...
nv4500 behind one..
just tryin to see if anything new stands out...

https://www.facebook.com/groups/vortec8100/permalink/2384156958469210/

Meh, there is lot of bad information passed around in pretty much all of those Facebook groups and the reason I stopped visiting there. I find it painstaking to read stuff there as there is no search function and it is always the same 10 or so questions that come up over and over and over and over. People these days just want to be spoon fed and ask a group for an answer rather than actually do an ounce of their own research. If one of them would spend a couple minutes on Google they would find tons of threads with that information.

The reality is putting a NV4500 behind an 8.1 is NO different than sticking them behind anything else, except the fact the correct flywheel should be used, which is a 12582964 8.1L specific flywheel. Not some cheap ass junkyard SBC flywheel like some of those guys believe in and also why they have oddball clutch issues. Use the correct flywheel and it’s a no brainer regardless which of your favorite clutch brands one uses.

A clutch to fit behind an 8.1 is pretty simple when the correct 12582964 8.1L specific flywheel really is used as there are two options…. I used Centerfoce Dual Friction part numbers as an example. Both examples require dowel pins to be removed from the flywheel.

1) DF024909 - Dual Friction, Clutch Pressure Plate and Disc Set, which works with the first generation external slave cylinder NV4500 bellhousings like used on the 1992-1995ish trucks or the Advance Adapters bell housing like I have

2) DF097310 - Dual Friction , Clutch Pressure Plate and Disc Set for use with the 1996 and later design internal slave bellhousings.

Both of these part numbers fit 454's for the respective year of the bellhousing type.

I just don’t understand why the same questions keep comping up over and over on there when there is plenty of info floating around the interwebs. Oh, I know why….. people today need spoon fed on social medial platforms and refuse to do any of their own research (y)
 
Last edited:
Top Bottom