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Project MULE - Expedition build on a 1991 1500 4x4 Suburban

I love the 8.1 vortec. I just find it to be overkill for our trucks we will never need that much power with the low gvwr rating on our trucks.

I plan to tow a small RV trailer (3500-4000lbs) someday so a stock 93-94 454 will go in. Plus you have added a lot of weight to your truck that I do not plan to add to mine. I think a 454 is your best option if you want to have decent mpg when towing. Plus the 454 tbi is such a easy swap in our trucks. Almost a drop in except for modifing the exhaust. All the power you will need with near stock set-up so you can repair easy when on the road away from home.

Plus it's super cheap. my local wreckers will pull a motor and trans with all accessories for around 500-1000 bucks.
 
Yeah I saw that AZblazer. the website and the way it looks just seems....:whistle:


As I keep digging I am more and more looking at a Vortec 350 with Tuned Port Injection and a full roller valvetrain and a stand alone harness from Howell. I can get more out of that then a 5.3 and still use original parts for my year.
 
y5mgisi said:
It's a no brainer to me to go 6.0. But anything would be better than the tbi 350.
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yeah i'd go LS too, seems like everything else is ancient technology. i went through the same thing, do i want a tbi 454, vortec 5.7, vortec 454 or an LS? i went back forth with myself for months, lost sleep over it. while obviously i haven't driven it yet, i'm still happy i went with an LS motor. tons of aftermarket support, lots of info out there, better mileage, lighter weight, cost, there are a lot of benefits.
 
I think you will be happy with the vortec 350 too. More than enough power if you try to keep the weight at something reasonable. Some expedition build just get way too heavy. I would also recommend going with the 4L80e, something about 350s eating up 700r4 when towing. But I had a stock 90 454 dually with a built 700r4 and never had an issue. I think it’s the lower torque having to constantly hunt for gears that overheats and stresses them too much.

Blowers are for hot rods and mall crawler not gas engine expedition trucks. Know maybe a old detroit diesel with a blower now that would be cool.
 
Just to advocate a little more for the ls route, or even just for the minimally modified route. The problem I have seen is that people take and do a tbi block with vortec heads, a 4bbl intake, 454 throttle body, adjustable regulator, cop car injectors, a random cam, and then they wonder why they can never get them to run right. With an ls like a 6.0 you get a plug and play 325 factory he with a butter smooth idle and no hassle. Even if you don't go ls, I beg of you, don't do anything with tpi! That will NOT get you where you want! Granted you can get the 6.0 numbers with a tpi or even tbi 350, but it will never run as all around good and easy as the ls. And that's a promise. I also think you just can't beat the reliability of something that's all oem. The ls motors especially are just stupid reliable. I personally even think they are actually easier to work on than anything with a distributor in these trucks. I know you probably won't go ls. And I can't believe someone on here was actually advocating FOR a tbi 454! puke! But at least try to do something factory as possible. Your peace of mind will thank you.
 
y5mgisi said:
Just to advocate a little more for the ls route, or even just for the minimally modified route. The problem I have seen is that people take and do a tbi block with vortec heads, a 4bbl intake, 454 throttle body, adjustable regulator, cop car injectors, a random cam, and then they wonder why they can never get them to run right. With an ls like a 6.0 you get a plug and play 325 factory he with a butter smooth idle and no hassle. Even if you don't go ls, I beg of you, don't do anything with tpi! That will NOT get you where you want! Granted you can get the 6.0 numbers with a tpi or even tbi 350, but it will never run as all around good and easy as the ls. And that's a promise. I also think you just can't beat the reliability of something that's all oem. The ls motors especially are just stupid reliable. I personally even think they are actually easier to work on than anything with a distributor in these trucks. I know you probably won't go ls. And I can't believe someone on here was actually advocating FOR a tbi 454! puke! But at least try to do something factory as possible. Your peace of mind will thank you.
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Can I get an AMEN!?!?
 
Don't get me wrong I love the LS engine, just i could never afford the 6.0 and I know for a fact(Buddy owned and towed with one) it won't get better MPG then a TBI 454 when towing and It Won't feel in more powerfull when towing. I understand when your not towing you can't compare them the 6.0 will win hands down. A MPFI engine will always run better then a TBI I don't know anyone that would disagree with that

The TBI 454 is the easiest and cheapest swap into this body suburban to gain towing power, nearly a drop in. I could get one swapped in a weekend with a little help and be well under $1000. I looked and every yard told me i would be on a waiting list for a 6.0 and it would cost me around 1000 to 1600 for just the engine. I could however get a 5.3 for around 800 all day long.

now if i had the money to do a 6.0 in my truck and had the time to do it right i would do it. acually if i had the money I would do a 8.1.

So i agree a 6.0 or 8.1 would be the best option if you had the time and money, and i'm sure you are right that it's easier then i think it is.
 
I appreciate the info but I think I am still going to go this route. I have two friends that went TPI in their jeeps and they turned out great. I am also taking with Howell fi on the harness and I will be contacting eaglemark here for a new burn.

I can understand your concern with a "mix and match" setup but to be honest these components would be more OEM to my truck then an LS.

The big problem is research. Unfortunately I have seen swaps where they just get this and that FI part and slap it together using some ecm with no verification . I already know that there are 3 different TPIs not including the vettes. Map or maf is another thing.

The guy I am getting this from did a TBI L31 head swap into his 84 burb. Had problems until he got a new ecm and had it burned. Besides I have more time then money.:D
 
When you talk to eaglemark you should see about upgrading to a 93-94 TBI computer. He will know better then I but i think it's easier to tune. I have a complete 93 harness that I plan to swap into my truck along with a 4l80 hopefully someday.
 
pma4x4 said:
1leg I will be running TPI not TBI. Like I said in the previous post I will be having eagle mark Burn me a prom.
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Sorry about that, misread that. I wish you luck on the build. I don't have much experiance with the tpi set-up so have no advice for you, eagle mark will get you up and running strong for sure.

Thanks for sharing your build.
 
Just to pile on the data points...

My last two trucks were both 2500s on 33" tires. One with 6.0/4L80e/4.10 and then one with 8.1/Allison/4.10 power.

In mixed daily driving, keeping up with traffic (70mph-ish) I got as much as 12.5 mpg, but more often 11 mpg with the 6.0. With the 8.1 I get 10 to 10.5 mpg.

Towing, I got about 9 mpg with the 6.0 and I still got 10.5 with the 8.1. Towing in the mountains, I would get 7mpg with the 6.0 and as little as 9mpg with the 8.1.

If you are planning a rig that will be "heavy" most of the time, I'd look into a pullout 8.1 from a van. Take a look at Larry's posts on sticking an 8.1 in the squarebody. A lot of the parts are factory (exhaust manifolds, engine mounts) though some need to be changed (crossmember to clear oil pan). You do get a factory engine that puts out a lot of torque and has LS management and relative efficiency.
 
Hmmm...a TPI setup with a 411 (Ls) ECM and harness...:whistle:
 
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