I've have had this GMC Suburban for 5+ years. I bought it with 48,000 original miles on it. yes, really! It came from an a lil' old lady in AZ who drive it to the grocery store for 18yrs. many of the seals were dried out but overall ran real well. I used it to tow a race car all over texas and neighboring areas. Its been showing its age.... it is a bone stock, carbed 454, TH400, with 14-bolt FF rear truck. basic doe-skin tan interior and exterior.
For a while now I'd been thinking of picking up a late model suburban to replace it to use for both towing & vacation trips. With fuel prices these days, the 454 just doesn't cut it and the comfort just isn't there. way too expensive to take anywhere.
I kept coming back to the reality of the simplicity of the older trucks. solidly built, basic, great lines, and somewhat oblivious existence to others wanting something to steal. old trucks are just too cool... I just didn't want to get rid of it, but gas is too expensive. This one already has the very heavy duty axle, suspension, & frame.
The newer '96-'99 vortec 350 2500's are interesting but I'd have to spend a bunch replacing parts to ensure reliability without the improvements of the most modern trucks. Texas is flat, so I can get by towing 6000lbs w/ a 5.3L, no sweat.
soooo Putting 1+1+5.3 together I've begun researching a 5.3L swap into this old, solid body. It will give me modern power & economy at a much lower price entry. We'll be able to take those week trips all loaded up in the old beast and maybe I'll get better MPG towing too. *I've already broached the idea many times with the little lady, and she isn't too put off by traveling around in a old rig. so it is a go!*
Anyway here are my plans:
Fuel system
- '88-'91 40G tank swap from TBI truck
- Walbro or similar in tank pump swap for 5.3L pressures (better than sumping or external pump issues)
- appropriate connectors & lines for the higher pressure fuel
-- thinking stainless tube (I can flare for AN fittings) or maybe modern stock type nylon tube & quick disconnects - Dorman products. I don't want braided due to concerns with E85 and teflon lined is expensive!
- early LSX vette stand alone filter/pressure regulator (depends on donor year engine single/double fuel rail)
Trans
- stock TH400 for now
- GM adapter plate & bolts
- stock drive shaft (just put in new U-joints)
- stock converter (good/bad match for 5.3L?)
Engine
- 5.3L 2002-2004ish L59 E85 truck drop-out unit
-- yes, I want to try to run E85 at some point
- integrate factory E85 fuel sensor
- all stock truck accessories from the 5.3L
--alt
--power steering pump
--ac compressor (?), still unsure about adapting lines.
--starter
- home made LSx to BBC motor mount plate type adapters
- locate engine such that TH400 location does not change
- stock 5.3L clutch fan
- current 454 radiator (<1000 miles on current one), maybe shroud too
- 5.3L stock intake ducting, MAF, & air filter
- undecided about drive by wire or by cable
- all 5.3L underhood wiring & fuseblock, to ease integration & expense of swap.
- postpone AC swap details until early summer
exhaust
- stock 5.3L truck manifolds or f-body manifolds
- integrate into current exhaust - already dual exhaust w/ cats
misc
- swap in 1500 350 2wd suburban front springs to drop front end down few inches post swap (will this work? this is 3/4 ton front end w/ springs for 454)
- black painted stock 3/4 ton steel rims w/ thin red pin striping
- black ~2" stripe where the original lower body side moldings were (screwed up paint underneith) w/ thin red pin stripe border
- tint front windows darker. all rear glass already very dark.
- rewire my 7-pin trailer wiring, its old n crusty now.
- sell off 454 to offset project cost
- Hawk Heavy Duty Brake pads (high Cf) - stops ok now, I use trailer brakes when towing. just need a bit more help w/o spending tons of cash for swap.
future
- schoenfeld LSx truck swap headers at some point.
- 4L80E swap & integration into 5.3L Harness (pending proof of concept w/ above changes)
- all chrome bumpers swap
- bumper mount brackets trimmed/welded to suck bumpers in an inch or two
- alternate fuel tank source for better long term compatibility w/ E85
Issues
- finding a COMPLETE setup. Mostly the drop-outs have cut harnesses, missing accessories, no pedal & TAC, and no fuel components (E85 sensor)
- figuring out VSS for swap & 5.3L with old carb'ed truck & TH400. I NEED my cruise control. Programing for engine to run stand alone w/o VSS is less than ideal.
- finding time to start the swap, I need to work on my daily driver camaro soon
yeah, yeah. I know. worthless thread w/o pics... none yet, but coming soon. A friend will be trying his hand at photo shop for the concept images.
feedback?
Morgan