Saying Good-bye to the 90 and Hello to the 72 Build. NEW:Hidden Exhaust

[GRINCH]

The better gear ratio in first will more than offset the slightly higher cruise RPM. Looking at the numbers at 65 MPH w/4l80 the rpms go from an almost too low 1,850 with 4.10s up to about 2,050 with 4.56s and a just right 2,200 with 4.88s.

I know these cruise RPMs seem a little higher than most shoot for but IME anything under 2,000 rpm in a full bodied, lifted pig of rig that most of us have ends up being doggy at best. The torque of the big caddy will help but there is much to be gained with a little more gear ratio.

This makes sense... But what do I know... I'm the one asking for help.

I can only go by experience I had with the 90. I live in Montana and there are no flat roads here. Every where I go is some is type of grade change. It was very seldom that I was able to use OD.

However, Greg makes a very good point. That the 4.10's will work for now and a gear change can be done later.

Problem is the locker!!!! The 14 SF I'm running is ok there is no cutoff for the gears. However, the 60 front is 4.10 and down and 4.56 and up.

Money spent now or money spent later!!! I'm sure I would be able to sell the 60 4.10 gears and locker but at how much of a loss.

When calculating this we need to remember the intended use. It will only be on the road 10% of the time... Trail riding 80% and 100YD Sand drags 10%.

In the charts there is not that much of a difference from the 4.10's to 4.56's
But the 4.10's to the 4.88.

Crawl goes from 55 to 65 and acceleration goes from 17 fps to 20 fps in first. Not a lot but a difference!!

 

[bigblock72]

The gear change isn't a big deal, you can get a spacer to use the carrier with the low gear sets. You might be able to get thick gear sets as well, can't remember for sure though.

But as I said in my last post you can run the 4.10s for now and see how it acts. The difference between 4.10 and 4.88 feels bigger than the numbers suggest especially in off the line performance. If you don't use it on road too much then I wouldn't be afraid of 5.13s either. I think you can get 5.38s for the small 14 bolt as well. If you're running overdrive you can get away with pretty low gears.

 

[GRINCH]

Update.. Waiting on parts… I ordered a whole bunch of stuff from DIY4X. Tabs, Brackets, Shackle flip etc…..

Ordered up the Crossover Steering kit for the 60 from ORD.

Found the best price on front Tuff Country springs from Carparts.com

While waiting I have completed scraping, cleaning and sanding the whole frame and underneath of the Blazer.

POR 15’d the frame and underside.

Once I get the axles done. (Gears/Locker) I will be putting on the flip in the rear and the 2” Front HD sTuff Country springs.. The reason I went with the HD’s is because I have a very heavy front bumper and a 12000” winch. If I don’t like the HD’s I can always pull the bottom leaf.

Hoping the 4” flip in the back and the 2” in the front will give it a good stance. I may play with the leafs in the rear if 4” is too tall. (remember I cut/reshaped my fender openings to clear the 37”s.
I have some Zero rates also to move my axles forward or aft depending on what it looks like.


Decisions, decisions…. So much to decide…

I am ready to order parts this week. So I guess it’s time to make up my mind.. Spend money now or later.??

I am really leaning towards the 4.88 gears. I know I could probably run the 4.10’s and may be happy with them. As stated earlier, the cutoff for the E-locker is 4.10 and down (Numerically) and 4.56 and up. Regearing now will only cost me another $600 and I should be done. I am hesitant going with any lower gear than 4.88 because of the thickness of the gear. I did a search for any thick gears and all I could find is 4.10 and down.

So who votes for the 4.88’s and who says leave the 4.10’s???

Next choice is Brand…. I prefer Yukon Gear but USA Standard gears are running around $100 cheaper a set.

 

[MTChevy]

oooo i like!!

 

[GRINCH]

I decide to go with the 4.88's and got them on order.

Ordered them from CCOR (Jason) Great customer service and SWEET prices. Better than I could find anywhere else.

Got the Eaton E-locker for the front to go with the Elocker I already have in the 14B.
and 2 sets of Yukon gears for the axles.

 

[Greg72]

I'm sure you'll be happy you spent the extra money for a quality set of gears.... they'll be quieter, run cooler and will probably be a lot easier to get a good wear pattern on during setup.




God, I love the smell of fresh truck parts in the morning... smells like victory!

 

[GRINCH]

I put some yukon's in the my 14 SF when I did the elocker 3 yrs ago. I took it apart last night and the gears are near perfect. They were super easy to set up too.

Parts are rolling in and now all I need is time.

Last hurdle to figure out is the gas tank. Since I'm going Fuel Injection I need an in tank pump setup. (Don't want a pump on the rail) Seen a few tank setups on here. Custom ones are big $$$ and my 90 Tank will hang down to far for my liking. But 31 gallons would be nice. I may look for a 25 Gallon Blazer tank. They are 2" less deep.
I had heard a van tank may fit too. Going to the JY today.
Or.. http://www.tanksinc.com/index.cfm/p...ategory_id=78/home_id=59/mode=prod/prd114.htm

But according to my calcs it's only a 16 gallon tank.
I think the Caddy Motor will be very thirsty....

 

[Big Blzn]

Hey, 90K5, I checked out the place (carparts.com) you got your Tuff Country springs and they are really cheap compared to the other dealers. About $280 for a set of 6" EZ Rides. My question is, do they come with all the bushings, etc? Are they poly or just the rubber type? Nice build thread BTW.

 

[GRINCH]

Hey, 90K5, I checked out the place (carparts.com) you got your Tuff Country springs and they are really cheap compared to the other dealers. About $280 for a set of 6" EZ Rides. My question is, do they come with all the bushings, etc? Are they poly or just the rubber type? Nice build thread BTW.

I just ordered some stock rear springs for $220 delivered. I couldn't find any decent ones from the junk yard and they still wanted $100 a set.

Bushigs appear to be the same one's ORD sells in thier kits. They have the same part # on the backs and grooved. I wish I would have known this. I ordered the whole bushing kit from ORD.

 

[GRINCH]

Still waiting on my parts from DIY4X... So I decided to move on to the gas tank.

I had to change out the tank since I was going to Fuel Injection on the Cad motor. My goal was to have it tucked up in the frame as far as I could and still keep maximum ground clearance. I thought about a custom built tank but decided against it due to cost. Since my 90 was almost stripped and getting ready to go to the crusher. I thought about trying to use the 31 gallon tank from it. It fit well between the rails but hung down to far. Instead I got a new tank/pump/and pickup from a 87 Suburban. 25 Gallon. It is the same dimensions as the Blazer 31 gallon tank but not as deep. The fill tube was in the center. I could have made it work but decided to move it.
I took the crossmembers out of my 90 so I could mount the tank using the factory straps and also will be able to use the factory skid plate with a little modifying since the tank is not as deep.
Without the axle in, I'm a little concerned that it is to far forward.
The crossmembers are a little short also. The 72 frame is just a little wider.
I thought about welding the crossmembers in but I read somewhere that you shouldn't weld crossmembers to the frame. Drilling the holes is also going to be a challenge for the upper part.

 

[jimbug]

Looking good! Plenty of clearance under the tank

 

[GRINCH]

Finished up the tank install today. One of the problems encountered was the vent tube for the filler neck. It came out on the wrong side of the fuel sending unit. I found a pre bent rubber line at Napa that I used. It looks a little kinked but it still flows enough.
I couldn’t find the material used to go between the fuel tank and the cross member as well as the straps. I thought of using some heavy duty tar paper but settled on using some cut up inner tube. Coated tank in 3m Rubberized undercoating.
Trying to use all the fuel lines from my 90 presented a slight challenge but after some careful re-bending they seem to be working out.
After talking with Rob at Affordable Fuel injection we decided to go with the later model fuel injection pump (45 PSI). Even though I will be going with a TBI unit he thought it would be better to have the higher pressure / volume pump. It will be controlled by the fuel pressure regulator anyway.
I also used part of the fill tube from my 90 to adapt the smaller 72 fill tube to the tank.
To recap
1987 Burb 25 gallon tank and sending unit. Remove and plug existing fill tube. Move tube to Drivers side rear. Cross members from 1990 Blazer. Fuel Lines from 1990 Blazer. Fuel pump from a 1997 K2500. Modifed skid plate from a 1990 Blazer.

 

[GRINCH]

More

 

[scottishdave]

looks really good man

 

[68MUDSTUD]

is that filler tube stock? Where did you find that? The PO of my k5 really focked me over... I've been trying to make do with a rubber hose... leaving a puddle at the pump everey time i fill up.

 

[GRINCH]

is that filler tube stock? Where did you find that? The PO of my k5 really focked me over... I've been trying to make do with a rubber hose... leaving a puddle at the pump everey time i fill up.

Sorta of Stock 72 and Stock 90 combined. I added the lower piece from the 90 right at the floor line. I mainly used it to covert from the smaller filler tube of the 72 to the larer tube size on my 87 tank I installed. Even was able to re-use the rubber gas line from the 90.
If you need some different pics than posted let me know.

 

[68MUDSTUD]

damn. Anyways, looks great bro!

 

[GRINCH]

UPDATE: (According to Greg, It's past due!!!)

I finished the axles, New 4.88 Yukon gears, Eaton E-lockers front and rear. New Rotors, Seals and Paint.
Since I had to move the spring perches on my 14 SF, I decided to buy some perches from Dan @ Ruff Stuff. They are a little longer (Which should help with axle wrap) and are already drilled to move the axle either forward or backward. I haven't welded them in yet. I am waiting to get the cage done and put in the Xfer case/Tranny and Motor to set the pinion angle. Used Dan's Disk brake brackets and the calipers from a front 1975 4x4, Dorman wheel studs 610-180 worked great to attach the rotor to the axle shaft.

All installed under Kert's Shackle flip in the rear with new stock springs and in the front under a set of Tough Country's HD 2.5" lift and a zero rate to move the axle forward. Offroad Designs HD spring hangers. ORD's greasable bushings in all of the Spring eyes. As a test I painted the rear springs with Graphite paint. They don't have Teflon pads and I thought the Teflon would help. It's called EZ-Slide.

Installed ORD's Crossover Steering. There was some concern from ORD if I would have enough clearance. Looks like I do. Completely went through the Dana 60. Full rebuild kit. The Steering box is from PSC and already ported for Hydro assist. I have the Ram but haven't installed it yet. Not sure of the mount at this time. Looked at the tie rod clamps but for some reason my tie rod is a smaller diameter than the clamps come. 1 1/8".








Here's a little sneak peek at the cage in progress.

 

[y5mgisi]

Nice work!

 

[GRINCH]

Not much left to do on the cage. I have a few gussets to put in and a grab handle or two. But I'm going to stay away from overkill on the pipe.
I will be running some sort of pipe off the B pillar but not to the floor. Probably just from the top to the side. Similar to what I did in the back.

The cage was designed around running with the top on or off and eventually a soft top.