My swap. 5.3 into a 1990 3/4 ton 4x4 Suburban.

[mcbassin]

Congratulations on a well planned engine swap!

[dorton]

Thanks for this thread. You have made it a little less intimidating than what I originally had in my head. Your thread has me looking at local scrap yards.
Thanks for sharing.

[y5mgisi]

No problem! My ck5.com thread is way more in depth and complete. So check it out too. Btw, Im into the swap about $1750. But when you take into account that i sold my tbi chip tuning stuff for $100 and my old motor for $250 I'm actually only $1400... Pretty cheap upgrade all things considered. Not to mention it will save me money in the long run at the gas pump too!
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[Gordonr1973]

Very good details in here....congrats on the swap!!

How did you manage the A-C hook ups (wiring) if you had time to do it yet?

[y5mgisi]

I havent messed with the AC just yet. All i can tell you is i think i can wire it all using the trucks "existing"wiring. Hooking it all up like the way it came off and not running it through the computer like the new style uses.

[Average Joe]

Cooool. Have you got any gas mileage #'s yet? A friend has a very similar 'Burb with the stock TBI 350 and is considering a ls swap. -Thanks, Brian

[jorgensensc]

I'm curious about the gas mileage also. I've got '72 3/4 big block burb that I'm considering this swap on. It is my daily driver and the 7-10 mpg is killing me. I wanted to keep the th400 that I already have, but there aren't many numbers posted on Mileage with that tranny. Most people swap the new tranny in. I'm thinking the th400 would hold up better and be cheaper to replace or fix if it does break down. If I could eventually get a gear vendors unit it would be even better!!! So please post your mileage when possible!
Thanks!!
Shawn

[y5mgisi]

Originally Posted by Average Joe

Cooool. Have you got any gas mileage #'s yet? A friend has a very similar 'Burb with the stock TBI 350 and is considering a ls swap. -Thanks, Brian

Im not too sure yet. Im doing a few things to it before i get it on the road. Im really doing all the stuff to it now that i would have done if i never would have had to mess with the motor! So, it still needs new tags before i start cruising it around. Im thinking the first of the month i will start driving it a bunch.

Originally Posted by jorgensensc

I'm curious about the gas mileage also. I've got '72 3/4 big block burb that I'm considering this swap on. It is my daily driver and the 7-10 mpg is killing me. I wanted to keep the th400 that I already have, but there aren't many numbers posted on Mileage with that tranny. Most people swap the new tranny in. I'm thinking the th400 would hold up better and be cheaper to replace or fix if it does break down. If I could eventually get a gear vendors unit it would be even better!!! So please post your mileage when possible!
Thanks!!
Shawn

Honestly, im expecting my my milage to go from about 10 average to about 13 average. I dont think it will be a big jump for me but i guess im just keeping my standards low so that im not dissappointed.

[y5mgisi]

I mostly did this swap (believe it or not) because i couldnt get my damn tbi 350 to idle right! I rebuilt it and did everything in the world short of pulling it and rebuilding it again trying to get it to idle right. Fought with it for 5 years and 10,000 miles and could never figure it out. So, i finally said F it! I wanted the 5.3 anyway so i figured it ought to solve my stupid idle problem without having to chuck another dime at that stupid 350! There was just so many times with the 350 where i would put it to the floor and think, "really? thats all i get?" The fact that the 350 came from the factory with less then 200 HP, there was no way i was going to keep spending money on something that was grossly sub par to begin with. So, for me, more then anything the biggest reason for the swap was the bad idle on my 350. Add to that that i gained 100hp and 35 ft.lb of torque and a couple MPG, and i was sold.

[Average Joe]

Heck 13mpg compared to 10 would be a 30% increase. Like you said 100 more hp and better fuel economy seems like a no brainer. Nice work.

[y5mgisi]

Thanks!

[y5mgisi]

Going back through this thread, i realize i left out a couple pics.

This is what i did for the steam line thing,



This is a few pics of how the intake came out.









And a couple crappy pics of the current little project of mounting the computer. If i would have started off with a truck wiring harness i would have just mounted the computer on the inner fender like the factory. With the option to mount it under the dash, i figured i might as well. So, there just aint no way your going to mount this computer where the orginal one sat. At least not without modifying the heck out of the glove box. So, it kinda fell into place right where the air recirculation door is. So thats where im putting it! Covering the couple inches that hang down with the factory flapper door diaphragm cover. Got a little bit to go on it still. But just to give you an idea.

[91Subbed]

Looking good!
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[justcuz]

Looks real nice!
My only concern with installing these engines in older trucks is the cam torque curve. I have a 2000 with a 5.3/4l60E/3.73 gears running 285/75x16 tires. It gets better mileage at 80 than at 65-70 mph. I heard that GM lowered the operating rpm range in the 6.0 engines cams in 2011. Does anybody know about this? BTW by better mileage I mean 17.75 to 18.13 mpg on Interstate 15 through Utah on my way to Wyoming. It normally gets about 2 to 3 less mpg when going 65-70. Actually am considering a 4.10 gear swap to get better mileage...or maybe the 6.0 cam if it runs at a lower rpm range.
I have to admit that before considering a big block or diesel engine swap I would definitely consider this swap before anything else in an older vehicle.

[y5mgisi]

My thougts are that if they work in a 2002 suburban, they will work in my 1990 suburban.

[y5mgisi]

Got it registered and insured! Took it for its first real test drive! All was well except the sloppy steering that it had forever. Definite power difference over the TBI 350! I will say though that it does seem to have slightly less low end torque but much more high end hp! All in all its definitely a well rounded perfectly useable power.

[y5mgisi]

Here's a preliminary 0-60.

[jorgensensc]

Very nice. I would love to see your mpg numbers when you get them. My Big Block is getting an abysmal 6.5 mpg city and 9 mpg highway. I need to figure out something to do soon.
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[y5mgisi]

The sucky thing is with the way gas prices is, it will be a while before i can actually FILL my tank in one sitting... At 37 gallons or whatever my tank is and $4.00 a gallon, thats about $150! I just cant stomach that. I can pay the $20 a week but cant do the fill ups!

[manimal]

Thats a very nice swap. I am still debating one of these or diesel....prolly diesel since I live in the peoples republik of kalifornia

[Mr. 250r]

how well did the stock 5.3 intake assembly go in where the battery would be... i guess at least that's where mine was because i plan on doing a heck of a lot of mudding and cold air isn't really a good setup and i don't like the filter sitting right off the intake i just like a stock look

[y5mgisi]

It was a cake walk! Two simple brackets off the stock battery tray and i was in business! Its not a "cold air" intake any more and just gets its air from that corner of the engine compartment but i feel its pretty safe from debris unless i did a lot of mudding.

[JCampbell]

Kick ass thread, Brother! Considering the same swap for my shortbed.

I was actually considering a 6.0 for my '88 K20 Sub. Now that you've driven it for a while, what are your thoughts? If you had to do it all over again, would you go 6.0 or keep the 5.3?

[y5mgisi]

Thats still hard question to answer. Reason being is im still running my 5.3 on a 571 LS1 tune! IT runs surprisingly well on it but it overfuels a decent amount at WOT and before the o2 sensors are warmed up and it goes into closed loop mode. I think its safe to say that the size of my wallet determines how i feel about 5.3 vs. 6.0 on any given day. As well, the amount of "work" that my truck does is taken into consideration. If i worked my truck harder, i would say it needs a 6.0. If i had more money up front and didn't care about mileage, i would go 6.0. But for me, less money up front, plus less money at the pump, plus only moderate towing, added up to a 5.3 being the right choice for me. I think that once i get a 5.3 tune in the computer and make it a 5.3 "performance tune", i will be more than satisfied with the power. On the flip side, if i had it my way, i would do a 6.0 with the zo6 cam, headers, and a dyno tune. That would be awesome!

[y5mgisi]

On a side note, for those that havent seen, I just got the truck painted so im pretty excited about that!