Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

It's a roller!

I finally had some quality time to work on the truck. I fabricated the boxing plates for the rear motor mounts, welded them in and then re-attached the axles. I now have a rolling chassis again.

Here's the right side boxing plate welded in:

Attachment 1337562

Here's the boxing plate with the axle installed:

Attachment 1337563

Here's the rolling chassis:

Attachment 1337564

Merry Christmas everyone!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

looks good!

i wish i could keep my garage that clean!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Very nice work! X2 on the clean work area!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Thanks guys. My shop is not normally this clean. I have company coming and decided to clean-up.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

It's a thing of beauty -

I hope that everyone had a Merry Christmas and a Happy New Year. I sure did. I spent nearly a month with family and friends both here in CO and in CA.

Even though I didn't make any progress on the truck, I was able to score some parts.

Here's the "new" fan pulley -

Attachment 1352663

Here's the spin on oil filter. The only way that it would fit was sideways (and this is the small one!). It should make for some messy oil changes...

Attachment 1352664

After a month off, I was going into truck withdrawal so I decided to do some mock up. I installed the engine in the chassis and installed the core support and radiator. Clearance between the fan and radiator and the path for the coolant hoses look good.

Attachment 1352662

Once the engine was in the chassis, I lowered the cab down over it. The cab is still about 8" high because of interference between the rear of the engine and the firewall "bump out" for the gas pedal. Even though it is still high, having the cab over the chassis is a thing of beauty...

Attachment 1352665

The evaporator will be very close to the turbo outlet. I'll need some exhaust wrap and a turbo blanket to keep things from getting too hot.

Attachment 1352666

I will need a 2" body lift to get the top of the rocker cover to clear the bottom of the nook in the firewall. I will have to modify the floorboard because the transmission is wider and longer than the stock transmission; but, even that doesn't look bad.

After a bit more measurement and documentation, I will get back on the drive train and exhaust.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Looking good. It sounds like you won't have to modify much of the fire wall at least.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Love it! I like your idea of a "stock look".

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

It's time to break some eggs...

I am halted on the drivetrain for a while. I am waiting for the output flange for the RT-6610 and the yokes for the NP-205 so I can work on the intermediate drive shaft.

So, I gutted the cab and started cutting. It is amazing how much damage I can inflict in just a few minutes with a reciprocating saw and a die grinder with a cutoff disc.

Three areas had issues. The first two were the "shoulders" of the engine. Detroit Diesels have the cam and balance shaft gears in the rear. The housing to cover these gears creates "shoulders" on both sides of the engine. Here are the cuts that I made to clear them.

Attachment 1359092

Third, the transmission is much wider and longer than the original transmission, so I had to cut the floor to make room. I had to widen the tunnel by about 4" on the passenger side.

Attachment 1359093

Here's the cab in the proper position.

Attachment 1359094

Here's the transmission clearance. Making a new "hump" to cover it will be a challenge.

Attachment 1359095

There are 2 remaining problems that I need to deal with. First is clearance for the buffer switch for the Jacobs Brakes. The switch extends about 2-1/2" beyond the governor to the passenger side. Here is a photo of the governor. The buffer switch replaces the screw that you can see on the left of the governor just below the name plate.

Attachment 1359096

The other problem is providing clearance for the tachometer drive. It is right of center on the engine at the rear just above the bell housing. I couldn't take a photo, there are just too many things in the way.

I'll keep working on the cab until some parts arrive.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

love it!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

It's looking nice. Jakes will be a nice added bonus!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

That trans fits better than i was envisioning, looks good. Is that with any body lift? That will be a nice trans and with that many gears, should be able to keep the detriot in powerband. Plus i think you can powershift these?

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Keep up the good work!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Yes, there is a 2" body lift. I can't go any lower without the valve cover interfering with the top of the "nook" in the firewall. I would also have to cut out a lot more of the firewall around the bell housing. Ironically, I could lower the cab further if I didn't have the Jake brakes. The spacer is almost 2" thick. There's no way I am giving up the Jake brakes...

I did quite a bit of research on the transmission and final drive ratios. The RTO-6610 with 3.54 gears will give me the proper RPM's at cruising speed. The gear splits match the power band of the engine perfectly.

The RTO-6610 is a non-synchromesh transmission. It can (and I will) be shifted without using the clutch. Even though I hold a CDL, it has been many years since I drove a vehicle without a synchronized transmission. It should be interesting re-learning how to shift.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Love the old detroits!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Part of me thinks man it's a shame to cut up such a nice looking cab like yours but then I think, WOW can you amagine driving this when it's done?
Keep cutting :lol: Awesome!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

It's been a mixed bag with parts this week. I ordered new body mounts and body lift and received the incorrect parts in both cases. However, I did receive the new yokes for the NP-205, new input shaft and output flange for the RTO-6610 and the intermediate drive shaft and all were correct.

Here's a shot of the new yokes for the NP-205. It came with 1310 size yokes with internal clips on the input and both outputs. I purchased 1350 yokes for the input and rear output and a 1310 yoke for the front output. That way both ends of the new front and rear drive shaft will match.

Attachment 1363680

I purchased a 1610 size output flange for the RTO-6610. It was the smallest size available. The transmission came with a 1710 yoke that was positively huge.

Attachment 1363681

I ordered the intermediate shaft from Drive Line Service of Fresno. They made me a shaft with a 1610 input flange and 1350 output yoke. They were great to work with and do nice work.

Attachment 1363682

I took advantage of the good weather and waiting for parts to overhaul the NP-205. Here are the guts spread out across the floor:

Attachment 1363683

Here's the case in black:

Attachment 1363684

Once I get it back together (I'm waiting for larger snap ring pliers), I will start working on the cross member and mount for it.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Well, I finally finished the overhaul of the NP-205 transfer case. It looks pretty good and it turns freely and smoothly.

Attachment 1366849

I was inspired by Ryan's "build your own" body lift and decided to do it myself. There is really no excuse not to do one's own lift when one is looking at a bare chassis.

Here is a front cab mount lifted and tacked into place:

Attachment 1366850

Here is a rear cab mount lifted and tacked into place:

Attachment 1366851

Here's the cab sitting on the mounts. Note the clearance between the rocker cover and the bottom of the "nook" in the firewall.

Attachment 1366852

I decided to slap the fenders and hood on to make sure that I have adequate clearance between the top of the engine and the hood before I weld the brackets on permanently. I have around 2" of clearance. That will work out well since I will probably put a blanket on the inside of the hood to keep the noise down to a dull roar...

Attachment 1366853

The cab and fenders look good on the chassis. The distance from the top of the tire to the bottom of the fender arch is a little larger than I would like; but, it is hard to complain about.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Nice work, and nice parts! Man, your body panels look super nice. It has a nice stance right where you have it!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

That sure is going to be a nice truck . We have a forklift with a 4 53 in it. That will bee a neat sound humming away under there. I love the orange and white my fav combo ever.

I just got a set of hub caps same as yours for my 56. Looking forward to getting them on. I do have to cut the centers out tho. There is a guy on here somewhere that has a nice thread on how to cut the centers out.

Keep up the great work. Oh ya love how you did the body lift. I didn't catch that on Ryan's thread . So I will give you the credit of doing if first. Lol.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

I was in a fooling around mood so I fitted the Jake brake switch and engine stop lever:

Attachment 1368266

I also took a first pass at the gear shift lever. It was originally a bit too long and bent in the wrong direction:

Attachment 1368267

Here's what it looks like after a little time with a saw and rosebud:

Attachment 1368268

I will have to complete the fitting after I put the seat back into the cab.

I started patching the holes that I cut in the firewall. I've found that it takes me a week to repair an afternoon's worth of cutting. I've tacked in the sheet metal for the driver's side.

Attachment 1368269

The throttle pedal will be about 1-1/4" closer to me thanks to the "shoulders" on the DD. I mocked the pedal up, it has full travel. The repair clears the engine so all is good.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Nice work. The fire wall is coming a long nice.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

All the king's horses and all the king's men...

I finally got the firewall tacked back together. The repair on the passenger side was much more complicated than I had originally thought. I had to get out the hammer & sand bag and the English wheel to make the compound curves required to get it repaired and looking good.

It all started with a little more cutting. I decided that the best way to make the repair to the firewall and floor was to section part of the firewall from the centerline to the passenger side and move it the 4" that I had to cut out of the floor.

Attachment 1378483

Tacking in new metal to fill the space was pretty straightforward.

Attachment 1378484

Then, I had to cut some more out of the top of the passenger side. The existing panel was curving toward the front of the truck too quickly. To make the clearance for the governor and buffer switch, I needed the section to curve abruptly at the far end of the passenger side.

Attachment 1378485

Here's the patch tacked in.

Attachment 1378486

There's plenty of clearance for the governor & buffer switch, the evaporator still fits (barely) and the tachometer drive clears as well. Life is good...

Attachment 1378487

Next up is the floor repair and the hump modification.

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

very high class. excellent work!

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

Nice work on the firewall! Do you plan to get an OE mechanical tach for the gauge cluster?

Re: Project Screamer - '72 GMC K2500 + DD 4-53T
 

I have a factory mechanical tach and air pressure gauge (the Fuller transmission uses air for the range shift). Aside from the Jake brake switch and the engine kill handle, the dash will look stock.