88GMCtruck's never ending 88 GMC build thread

[88gmctruck]

Well, a few things are set in motion a bit quicker than expected....

Motor came into the yard where Brandon and Devin work... 1990 TBI 454 with 76k on it. It'll be pulled soon and will be going into the 88 in a few weeks. Along with that the transmission is getting a freshening up, and new exhaust will be in the works as well.

 

[Ed HD]

Sweet. Can't wait to see the finished result!

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[btfarm]

Big block's gonna make that a ground shaker!

 

[Ed HD]

Any planned mods or just dropping it in OEM?

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[trouttrooper]

Big block's gonna make that a ground shaker!

And a wallet drainer.....

 

[Darkrider]

And a wallet drainer.....

And a clutch/tire killer lol

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[88gmctruck]

Big block's gonna make that a ground shaker!

Oh yeah! Nothing beats the rumble of a big block.

Any planned mods or just dropping it in OEM?

Haven't decided. Might just drop it in stock, although cam and heads is mighty tempting.

And a wallet drainer.....

Naw, big blocks don't use fuel. I actually expect it to get better mileage than the 350 while towing. I'm getting 7 right now.

And a clutch/tire killer lol

Quite possibly. Lucky me my running gear is pretty much 3/4 or 1ton rated.

--------------------------------

Have had a busy week! Lots of things going on at work, and on the project front for me.

Saturday I pulled the pinion & carrier and put new bearings in it. Super easy job, had everything apart in 30 mins. After re-installing, I gutted the passenger door and put a new door on the truck. Color is a bit more faded, but it's better than dented.

I also picked up another project this weekend.... 3 Suzuki LT250R quads, complete with a metric ton of spare parts.

 

[Darkrider]

Ironic....i just finished reading this thread over on GMT400 :lol:

 

[trouttrooper]

Naw, big blocks don't use fuel. I actually expect it to get better mileage than the 350 while towing. I'm getting 7 right now.

I keep a gas log book in every vehicle I've owned. My 2005 beast with the 8.1 gets a better yearly average mpg then the 1999 2500LD 6.0 did when I had it. Yup, the 6.0 got better empty, but put a load on it and the mileage fell through the floor. I generally only drive my truck when I need to do "truck" things so most of the time it's towing or hauling something.

 

[3500GMC]

I'd like to have one of those Quadracers.. cool.. Used to terrorize with one of those in the late 80's :thumbsup: IIRC mine was an 87... It had the 5-bolt rear wheels and the engine had the separate Reed housing.. Back then they were hard to beat. Had a big 'ol chrome top end pipe that must have been 6" in diameter at the expansion part.. Those were some pretty fun times.

 

[88gmctruck]

It's time. Well, almost time.

Picked it up last Sunday. Well, actually pulled it, but yeah. 1990 Chassis Cab 454 TBI with 76k on it. I even got to drive the donor truck. Looks a little rough, but it was actually spotless inside and the motor was WELL taken care of. Fluids looks proper, and the filters were all wix brand. Here she is. I have the motor with all the accessories, harness, ECM, 34" radiator and shroud.

While I was up at the yard the tires got switched around. 35s are back in place, now she looks proper again.

And put the 6-lug Racelines on the 285/75R16 Cooper ST, likely will be going on the yellow truck tonight.

 

[Burning oil]

Hey David, can you messure the hub hole diameter of those wheels for me.

 

[88gmctruck]

The racelines? They are standard 4.25" center bore like 90% of aftermarket 6-lug wheels.

 

[Burning oil]

OK thanks I was wanting to confirm that. The GM wheels are 3" hub. Im trying to build up a full float 6 lug axle. A 4.25 hub would make it much easier.

 

[88gmctruck]

I've seen a few examples. There are premade 6-lug FF hubs available for some coin, or you can get an 8-lug one welded and re-drilled for 6 lug. In either case you have to machine some of the hub and axle down, and use a small diameter axle bolt.

Not my pictures obviously. The first one the guy machined down a stock wheel in addition to the hubs. Second one was with just machined down hubs and an aftermarket 4.25" bore wheel. I thought about going this route but in the end figured it was more cost effective to just put 8-lug hubs on in the front and get a set of wheels off craigslist. I can sell the 6-lugs I have for more than I paid for the 8-lugs on there now.

 

[Burning oil]

Thats pretty much exactly what I was thinking. I have seen some other pic's of the mod also, but no one keeps the drum brakes, I wonder why? I want to keep my 13x3.5 pads and parking brake. Seems like I would just need to drill the drum for the 6 lug also?? Any thoughts?

 

[88gmctruck]

If you drilled them the same why not? If your using a GMT400 axle wtih 3.5"x13" brakes then your drum over hub anyway. My axle is from a CUCV, it's 3.5"x13" brakes but they are drum behind hub.

 

[Burning oil]

Exactly, I wonder why all the kits and pepole doing the home brew convertion are going disc?

 

[88gmctruck]

Discs are lighter, easier to service, etc. Most people converting these axles are offroaders. I kept the drums for towing, and they were already there.

 

[88gmctruck]

Just a bit of an update. Had a party this past weekend, haven't done much in the way of truck work. I have been researching on it though.

Turns out, the motor isn't what I thought it was. Being the truck was a 1990, it has the steel accessory brackets, spreadbore intake and TBI adapter, but should have had stamped steel valve covers.... A 1990 was a Mark IV motor.

The aluminum covers threw me. So after pulling a valve cover, researching the casting numbers on the heads and block it turns out this a a Gen IV L19 service replacement block. Which means it has a good deal less than the 76k miles than the truck actually had. It also explains why the motor was so clean.....

This is not a bad thing. Been looking into swapping heads to a smaller chamber to up the compression along with a cam and intake, and some fuel changes. Should put me right around the 400HP mark.