1988 Chevy Crew Cab build
 

Hey guys, thought I would share my build. Please bear with me as it will be a slow build (tight funds and truck is 35 mins away)

started life as lowly 2wd 1ton work truck with 350tbi and 4spd manual, previous owner converted to 4wd with axles,tranny and transfer case from 1/2 ton meaning weaker axles 3.08 ratios and a 700r4 AUTO.

first day I had truck I swapped the axles for a set I had laying around (dana 44hd front and 14bolt FF rear with 3.73 gears) and lifted truck 4" with used lift I also had laying around...along with 5 35x14.50x16.5 STA trailbreaker tires bringing truck to this point

drove truck for about a week and got bored with the gutless 700r4 3.73ratio and 35" tall tire combo (truck is really heavy)

so out came front axle,trans and transfer case,and springs

in went 52" chevy rear springs with AAL's, 2.5ton GMC front axle (with 6.17 gears), 5spd manual NV3500 trans and np241 transfer from newer body style 89 chevy truck... for now has 39" tall stock military 9.00-20 tires

2nd pic is with stock 4wd 2500 gmc so you can tell how much lift is on it

truck beside it is a 6.2L diesel truck that I am pulling motor from for this swap... I have hummer headers and a M90 eaton supercharger that i am fabbing intake for on top of 6.2... was going to turbo but with engines low rpm manners I thought the turbo would only be useful for very small rpm band...so super charged it will make boost at idle and top out at about 8psi perfect for slow revving diesel

also here is picture of tires I have for truck... they are 425/65/22.5 super singles from front of cement trucks

equal out to be about 43" tall 14" wide AT tire


using gear ratio calc program should be running around 2288 RPM @65mph PERFECT!! campared to a stock military chevy's 3288rpm @65 (th400.4.56 gears and 32" tires stock)

the 2.5 axles are from a 1950's GMC military truck.. they are normal faceload style instead of "toploader" like rockwells.. one wierd fact about them is they are setup passenger side high pinion reverse rotation front, low pinion standard rotation rear using the exact same carriers.. all you have to do up front to be able to run a standard transfer case (instead of the huge heavy military one) is either flip the front around from high pinion to low pinion staying passenger side OR flip axle front to rear and stick the carrier in the spot where cover used to be, making it a driver side low pinion standard rotation.

if you want to keep it passenger side pinion you have to notch the housing for the ring gear and shorten one inner axle shaft, if you flip it over to the driver side you dont have to do either but requires different transfercase (which I already had along with newer 5spd from a IFS equipped chevy)

there are few different ones

10 spline set with 6.67 axle gears (weaker axles)

10 spline set with 7.20 axle gears (weakest axles and VERY RARE 2yrs only I think)

27 spline set with 6.17 axle gears (strongest set)

by comparison the 10 spline axles are about as strong as stock rockwell axles, the 27's are little stronger, but people like rockwells because of the top loader design and there are aftermarket parts for them... onlything available for gm's are stock replacement bearings,seals and a detroit locker

I went with them to try and keep my truck all gm and because they have a better gear ratio for the street unless you are running super tall tires (rockwells come with 6.72 gears)

also drum brakes with 2 wheel cylinders per drum, I am working on a disk setup right now though

here is pic of the inner axle at the splines

here is a cell pic from this weekend you can see bumper is flat blacked but ran out on brush guard so i will have to finish it up later


got the rear frame mounts finished up for triangulated 4link using bushings at frame end and heims on axle

sounds like a cool project keep us posted i have a restored 83 reg cab short bed im getting ready to do but i have rockwells toploaders for mine. 6.72ratio 35" tires and a turbo 400 trans can we say hi rpms at 60mph

Looking pretty sweet so far.:U:

Id love to see a Cummins in there but old Chebbys are way cool...

thanx guys, yeah I would love to have a 400hp cummins in there but thats alot of $$ for something I dont really need.

I also started the project with idea to keep as much of it GM as possible, I had originally tried to source the 8.2L fuel pincher diesel/5spd eaton combo that gm put in buses and dump trucks....but again $$$ for a good running one or $$ to fix a broken one.

Truck is just going to be weekend cruiser for me and GF, might hook it to a sled once or twice for fun.

paint plans are dark blue with icicles hanging down from the body line, interior will probably be either blazer buckets and console up front and stock bench in rear OR 2 dodge ram quad cab benchs with the seat belts in seats.

hey good luck on this project it looks like you got it handled let us know if you need any advice:ok1:

ok need advice... anyone have experience with doing this swap from gas to diesel in these trucks? from what I have seen it is pretty straight forward tear everything from donor and stick in project truck including the gas tank,dash(gauges),and wiring in cab and out under hood...along with the fuel/water seperator...and also hydro boost brakes

is this about it? any guess on how long this might take your average wrencher with a engine hoist power tools and a tool monkey or two??

probelm is winter is setting in and I have to have one truck or other to drive... so should I moth ball the big truck for the winter and drive my old trusty and rusty 6.2 2500 for now? or is it possible to pull the switch in a weekend in a black topped driveway?

i suppose you could do it in a weekend if you had 20 helpers and unlimted funds. i would give it a week or two at the dead minimum. getting the motor in is the fastest thing. its the little things that kill your timetable (wiring, making drivelines, cooling system, hydroboost, etc, etc, etc) it took me about a month doing it the right way working on it every day

yeah I have been down similar roads before and its always the nuts/bolts wiring that killsa build.. for me I think it will be more like brake lines, steering etc because both trucks still run really (gas tank is out of big truck but thats easy). thansk alot though just reading your post and thinking about past experinces make me think should just leave the truck gas for the moment and run little truck as dd for while longer

Sweet truck!
I think it looks totally badass in the first picture. :rocking:

thanx I have had alot of chevy trucks but this is only my 2nd crew cab.. other one was rusted up pretty bad and I'm no body man so it left.

:c:

Nice. I have always liked that vintage Crew Cab. Need to get my 76 built someday.

looks like an awesome project so far. :U: Keep up the good work! :rocking:

thanks guys been working on the rear 4link but its been raining me out before getting much done, only problem with a truck that doesnt fit in garage (too many other cars,bikes,tools etc in way).

well it rained today but it was off and on enough that I got my rear axle mounted :5: actually had to throw a jacket over the mig welder while under the truck tacking the bars in place before pulling them out to finish weld them

looking good:U::U:

sorry been long time with no updates got litle done before hurting my back and now being out of action for 3 weeks

bought 2 sets of rear flares for my truck so front would match rear (openings are longer and lower) only got one on so far to make sure it would work

:tu: looking good..

id like to get my self a crew cab like that

sorry for no updates

just got the 6.2 stuffed in place with the 5spd and new hd clutch installed, also got the 2wd steering box attached for crossover steering and put straight stick steering column in truck

got new 4 core radiator in truck and having wheels made so hopefully will have BIG update when they come in

FINALLY got wheels back from welding shop, mounted the tires by hand 1 pry bar 1 sledge hammer 2 people (me and dad) 45 mins for all 4. I also thought to try the airsoft bb for balancing trick instead of the golf ball idea i was going to try after I heard the golf balls may damage tires from inside and would be less accurate at balancing, so in went 2500 .25 gram airsofts for about 22.5 ounces of weight inside each tire.

Lookin sweet! :rocking:

should also note in the pics i have yet to flip my front hubs in. so the front will be same width as rear instead of sticking out so far (the fronts actually stick past the fender flare the same amount as the rear sticks out with no flare)

Looking good!

thanks guys just waiting on a different machine shop to finish with my disk brakes for the front so i can flip hubs in.. took another pic of it though

as you can tell its not REALLY tall 88" to top of drip rail on cab on a truck with 44" tall tires (actual height)

not a huge update but I did get all the fender flares mounted on truck... bumper mounted etc

Awesome build :tu:

thanks! few more pics... plan on working on it tommorow


noticed in pics bumper looks crooked so I'll have to see about that (probably mounts since I had to space them out to clear the fender flares)

Great looking project. Nice work.

got my big brakes back from machine shop and installed... 15.3" diameter 1.5" thick rotor held on by 6x 9/16" grade 12.9 bolts

12" adjustable wrench in pic for size comparison

2nd pic shows clearance all around steering knuckle, glad did the measure twice cut once approach

just two pics with the front hubs flipped in on disks

Cool truck!