66 4x4 my sons new project

[argonaut]

Ah, okay, now I remember how I decided the relative vertical position of the hangers!

First I mounted the shackle hanger in the rear. It aligns horizonataly with the mounting position of the old shackle hanger. However there isn't much of an option, you pretty much have to mount it so that the bolt holes are centered between the top and bottom of the frame (same as on the donor truck). I then took some measurements and figured the effective drop of the rear spring eye, compared to stock, given this new shackle hanger location, and the longer shackles. I think it was around 4-5" lower.

Second I dropped a plumb bob at the location for the stock front hanger eye bolt. Then I positioned the front spring hanger with its eye bolt location about 5" lower, and rotated the bracket so that it was effectively oriented perpendicularly to the bottom of flange of the frame (since the frame is sloped and tapered in this area. This was necessary so that the backing bracket would sit flush with the under side of the frame flange and bolt together with the frame crossmember.

This resulted in spring geometry similar to the stock geometry, but without using the huge 5-1/2" stock lift block, and with a longer shackle. If I remember correctly I also lowered the front of the spring a little more than the rear, as this gave me a spring angle more similar to the newer model trucks I was using for reference. My logic was that the newer trucks probably handled heavy loads a little better and rode a little more comfortably, and thus some engineer had determined a more optimal rear spring and shackle design to accomplish this. Hopefully it works out!

[duallyjams]

Perfect thanks

[argonaut]

Tire sizes. I lined up a selection of radials that I had around the house for a comparison. From right to left is 31x10.5R15, 235/85R16, 33x12.5R15, 315/75R16.

Ideally I want a tire roughly sizes at 35x10.5, but the only tires I can find in this size are Interco's SSR 35x10.5R16, a radial, roughly $400 each or the TSL Q78-16, a bias ply, roughly $300 each. I've heard bias play tires aren't that great for daily or highway driver vehicles.

I want tall and skinny, but for now I might just put the worn out 315/17R16 Xterrains onto my 16x6.5" 8-lug rims to get a feel for ride height.

[argonaut]

I was losing some sleep this week over the fact that I used 3/8"-16 bolts to reassmble my chassis. So this afternoon I bit the bullet and bought all new 7/16"-20 fasteners, and a 7/16" drill bit, and started removing the bolts, one by one, and replacing them with the larger, fine thread ones.

The benefit being that the 7/16 fine thread give me about 60% more clamping force at the joints compared to the 3/8 course thread, because of its bigger minor diameter. Also the fine thread pitch give a more shallow thread angle so it should resist vibration loosening a little bit better. Lastly the larger bolt head has more bearing surface. Best of all, I can sleep soundly tonight

[quadzero]

Thank you for that information, really appreciate it. I sometimes get that losing sleep feeling and the only thing you can do is go back and do it the way you think it should be especially at this stage of the game. Your logic for the bigger bolts makes perfect sence.

[gmjim4x4]

Very nice work Jason! Hey, have you come up with the shock mounts for the corp 14 yet? I scored the same set up you have from a 78 3/4 ton with 6.2 diesel. The dana44 with the 8 lug hub and the corp14 FF. I am watching your build very close and you are a true craftsman. Hey, why did you put fabbed hangers on the front if you didn't change springs? just wondering (you did a fantastic job) Keep up the good work!

[argonaut]

Gmjim,
I made new brackets for the front springs because neither the 66 brackets nor the 73 brackets would work for me. The stock 66 have an inner width of 2-1/2", meaning that standard 2-1/2" wide spring would contact the sides, not having any clearance. I think this was the stock design but not what I wanted. Then the 73 stuff is made for a 3" wide spring ends so they are 3-1/2 wide. Plus the front uses the radiator support bracket as an integral part, riveted on. So I thought it would look messy to modify it. Then the rear shackle hanger simply won't mount in the stock location, nor would it work with the stock bell housing crossmember on the 66. I can show you what I mean with photos later if you want.

I have a plan for the shock mounts but I havent welded the brackets on the axle yet. Basically instead of having the tabs straddle the shock putting it in double shear I will offset the tabs, with a collar between them, then mount the shock on the side, in single shear. Similar to the upper mount. Also the lower end of the shock will not hang lower than the axle tube, at least it wont as long as i can get adequate damper travel without doing so. I want as few things as possible hanging low.
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[argonaut]

This weekend was filled with turmoil over the right path to take with the drivetrain on the pickup. I pulled both SM420 transmissions I have apart, pressed all the sprockets off the shafts and inspected them. The hope was that between the two of them, I'd have a enough good parts to put together on solid transmission. Well I wasn't impressed with what I had to work with. One had rusty gears from sitting outside for 10 years (blame it on my hasty youth) and the other had some wear.

So today I decided to haul the two SM465 transmissions up from the stock pile of parts in the back, pop that tops and check them out. I wasn't expecting these two to look any better. Boy was I surprised to see that both of them, even the one that had been outside for a year were incredibly clean inside. The first came out of my Dad's 69ish K10 pickup. He swapped the SM465 and divorced T221 out for an automatic and an NP203. Based on the condition of his truck when he got it I thought it would be rough, but its was actually very clean inside and the oil looked clean too. The second is actually the SM465 + NP205 combo that came in my 73 K20 parts truck. This truck had seen some abuse too, but much to my surprise it looked brand new inside.

I first considered just putting the 2WD SM465 in and still running the T221. But then I figured what the hell. May as well upgrade both at once. And these two units are easier to find parts for and better supported by the aftermarket. So, although I feel like I've betrayed the 66 a bit, here it is:





Now that I've committed I've got a few new challenges (in addition to finding a good home for all these SM420 parts that have taken over my garage).

1) Because the 60's pickups, and early 4x4s, all had the engines sitting further back than the 70s and newer pickups, my front driveshaft will have to be lengthened. The rear will have to be shortened regardless as the donor truck was a longbed. However the lengths are dependent on the outcome of the additional issues below.

1) The shifters now site further back than the stock setup. The trans shifter is ~1-1/4" further back, and the transfer case shifter is about 3" further back. Aside from the potential for the TC shifter to hit the seat, I also wanted it to look stock inside the truck and not hack up my nice high hump. The next step here is to get the cab on the frame and actually see where the shifters line up and where the interferences are. Then I can decide about the possibly moving the whole assembly, motor + trans + tc, forward and inch and a quarter. I also have an idea on a custom bent shifter for the transfer case that would utilize the stock hole on the driver side of the 66.

3) If I do move everything forward I end up with other problems. Tight clearance up front between the water pump and the radiator. I'd have to eliminate the stock crossmember than spans at the front shackle mounts (former bellhousing support), and swap in a 67-72 K-series engine crossmember (I may have found one already though).

Also, the frame is taller on the 60-66 than the 73+ pickups. Which means that the 73 trans crossmember won't mount up to the bottom of the lower frame rail as intended.



No biggie though. I'll just make a simple pair of brackets out of 2" angle that will look something like this (only with a bigger, thicker piece):

[duallyjams]

GM had a half dozen different shifters for the np205 , some would be close to were the t221 shifter would be. I think a 70 truck had them.
On the tires you move up to a 17" tires would give you more choices on tall skinny tires.

[argonaut]

I test fit the cab on the chassis with the new powertrain setup and I learned a few things. It was nice to see it resemble and actual truck again, even if only for 30 minutes.



It turned out that the firewall and the valve covers on the big block were just kissing. There was almost nil for clearance at the distributor too.







I know some other members here have gotten away with running a big block in the stock position. I was hoping that would work for me, but alas I'm not overly surprised that it didn't pan out. Based on this test fit I knew I needed to move the whole powertrain assembly forward by an inch or so.

Then I poked around the inside of the cab and the hump where the shifters come through. The SM465 is about 1.25" longer from its front face to centerline of its shifter. So I decided to move the motor forward 1.5".



I didn't want to move it too far forward. When I had the big block in my 2wd 64, I moved it the full 3" forward and it really seemed to shift the trucks weight too much over the front wheels. I also didn't want to lose all the space between the water pump pulley and the radiator like on my 64.

Anyway, I didn't get anymore photos, but I pulled the cab off and powertrain out. Then I removed the stock engine mount brackets, as well as the bellhousing crossmember. I then installed the 67-72 K-series engine crossmember and clamped it in the target location, with the motor mounts exactly 1.5" forward of the stock position. I put the 73+ transmission crossmember about where it belonged. Then I put everything back on one more time to make sure it would all fit okay, and wouldn't require any frame trimming. Everything fit fine so now I have to clean and paint the new crossmembers, drill the frame and then I can put the motor, trans and transfer case in their final resting places once and for all. Whew!

The real kicker here is that I would not have been able to so easily move the powertrain forward if i hadn't gone to the married SM465-NP205 setup from the divorced SM420-T-221 setup. And the reason is that I wouldn't have been able to just shift the motor mount brackets and bellhousing crossmembers forward. They are both mounted to angled parts of the frame and would have required extensive rework and fabrication to make work, or just completely custom crossmembers. So, in the end, everything would have ended up the same either way.

[travz500]

so did you use the 47" front springs off the 73-87 frame? if you did, did you move the shackles for the rear of them back and make a new hole or did you do something different

[argonaut]

Trav,
I used 44" spring up front, and 52" in the rear. So I used the stock mounting positions but made new brackets.
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[travz500]

ok was hoping you used some 47" so I can see how you did that I think i am gonna use my 47s since I got a 8" spring lift on my newer frame but I am using my old 65 frame soon as it gets shortened to fit the shortbed think I may just fill the hole where the rear shackles go thru the frame and then make a new hole so the longer springs will work out thanks for the information and nice build so far

[argonaut]

Trav,
That is exactly how I would do it. I'd fill the hole, then move the front mount 1.5" forward, and the rear mount 1.5" rearward. Unless of course you with to offset the axle forward or backward a bit. What spring hangers and brackets are you going to use? You might also think about the angle you want your shackles to be at when loaded. This may change the location of the shackle hanger.

[travz500]

gonna use all the stuff off of my 87 blazer frame its all in good shape

[argonaut]

Finally got my new lift springs in yesterday! Now I can set the suspension and steering for good (as long as it doesn't rain this weekend ).

[argonaut]

Swapped out the bushings and mounted up the 4" lift springs, front and back, this afternoon. The fronts were about 1.5" higher, and the rears 4" higher, than what I had on there previously... and now it sits quite a bit higher than I thought it would! Maybe too high?









I guess I'll keep it this way and finish the build. It will definitely need 35" tires now! Hopefully it will sit an inch or two lower once the powertrain and body get loaded onto it. If I still don't like how high it is I'll drop it down with 2" lift springs later on.

If all goes according to plan I should have the crossmembers and powertrain back in place by the end of this weekend.

[duallyjams]

The weight will bring it down some.

[splehigh]

Very nice looking frame

[MTCK]

Awesome build! I'm not sure how I missed it previously... I got a good chuckle out of your hardware swap too. I bet the guy at Fastenal loves to see you coming. Probably a very smart move, though. I was going to say look into some 255/85r16's, but I think you might need a little more than that with as much lift as you have. I think I've seen some of those spec'd at 33.7 x 10. Keep up the good work!
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[Auctioneerhere]

This is very helpful information with great pictures. Thanks!

[1985-GMC]

Nice project, this thing is going to be sweet!

[RANDY COX]

Hey,your doing a great job man,lot's of work,truck is gonna look great,I'm lookin at a 64 3/4 4x4 fleet short bed,that I'm wanting really bad.just wish I could sell my car,to have the funds....anywho keep up the good work,can't wait to see it completed....ROCKS....

[argonaut]

Hey! Thanks for all the support, guys!

I haven't done much on the pickup over the last month because I was saving to maybe buy a house. Anyway, I didn't end up buying it so now I've got to make up for lost time! My goal was to have this thing all put together by the first of the year. Woops!

I did manage the regasket and seal the transmission and transfer case. And refilled them, and my axles with synthetic gear oil. Everything looked really clean when I opened them up. I tell you what, I can't believe how easy the np205 is to disassemble and reassemble compared to the old t221. I'm glad I made the swap. Now I just need to replace the rear main seal and install the new one piece oil pan gasket on the 402 and I should be ready to drop the whole powertrain back in, once and for all.

Then I need to get the steering box hooked up; since I changed my mounting method and cut the mounting blocks off of the frame in lieu of a couple plates to sandwich the frame and spread the load from the gearbox bolts.
Then I can get all of the custom stainless brake hard lines bent and installed and start getting the body back on.

Whew! Lots to do and not much time to do it in!
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[argonaut]

Doing some serious work on the pickup these days.

Welded up the crossover steering linkage. Cut the old steering box standoffs off the frame. Then used my old 2wd power steering brackets to sandwich the frame. Modified the inner bracket so it now has a 90 degree brace and gusset to the front crossmember. Should be pretty strong now.



Dropped the motor, trans and transfer case back into the frame and finished bolting up the crossmembers.





Picked up a super cheap set of F*rd 3/4 ton 16x7" aluminum wheels. I really like the look of these, they have a pretty neutral offset. The previous owner didn't tighten the lug nuts down so the holes in the wheels were destroyed. I had them drilled out for steel inserts at a local shop. The job was a little sloppy but these are just to use until I can get the steelies blasted, powder coated and put some 35x10.5" TSLs on them. I'm basically copying DirtyLarry and running radials on the aluminum wheels and bias play on the steelies. Sorry Larry!



My little brother was helping me swap the wheels over. Have to start them young you know!





Fabricated a mount bracket for the clutch slave cylinder. I think this may hit the cab though, so I might need to cut the top mount off and use the side mount boss for the old mechanical pivot bolt.



Also picked up a package at the post office containing this little guy.