'72 K5 - Greg's @MightAsWellK5 Build

[Greg72]

Thanks guys.

I'm doing some traveling for work this week (Gotta sell 500,000 brake pads! ) so no real progress since those last photos.

I'm hoping to get back to it after this weekend.... I'm really excited to start cutting and re-shaping that firewall area.

 

[NV_K5]

Thanks guys.

I'm doing some traveling for work this week (Gotta sell 500,000 brake pads! )

Is your real name Chris Farley

 

[tRustyK5]

It's Greggy boy!

Rene

 

[Greg72]

2008.05.21 - UPDATE: I'M BAAAAAACK!


I get the impression that there are a lot of people subscribed to this thread...wondering lately why this post is dropping off the forum and into obscurity.

Unfortunately, I've been doing a lot of traveling for work so the Blazer has been sitting patiently waiting my return. It certainly seems true that when it comes to projects like this you either have time but no money, or money but no time. It's awfully rare to have both at the same time.

In any case, Memorial Day weekend is here... and I took an extra couple days off to stretch it to a glorious 5-day weekend. My plan of record is to get out into the manspace and finally figure out how to modify the firewall to get the driveline into it's final position. Once I finish this cup of coffee, I'm heading out to the shop.

June is going to be another crazy travel month, so I'm hoping to get you guys some progress pics now that will carry your interest until I can get back into the shop in July.

Stay tuned for new pics in the coming hours / days....

 

[Yukon Jack]

I'm sitting here drinking coffee at work and I sure wish I was heading out to your shop to watch/help with the next part of your project! Will be cool to see how the next step progresses.

 

[Greg72]

UPDATE: HEAD SCRATCHING AND THE RETURN OF THE CUTTING WHEEL OF DOOM

Not a bad day in the shop... This 3-D puzzle definitely is messing with my head. If all I wanted to do was stretch the firewall opening laterally, I'd probably be showing you photos of everything stitched back together by now. Wanted to also set the engine back a few inches adds a whole extra dimension (quite literally) to the metalwork. Things are going to be especially interesting in the pedal area, since I don't really want the gas pedal to end up a lot closer than stock.

Here's a shot of the "extra" firewall that I've begun cutting into replacement sections. This will replace all the sledgehammered metal in the cowl from the previous owner.

After literally 2 hours of just staring at the firewall and trying to figure everything out in advance, I had to finally just force myself to make a few cuts to get things moving. There are braces behind the brake pedal area on the driver's side, so I started on the passenger side.

Once the cutting began, it wasn't as hard to keep going. I did the driver's side also avoiding the inside bracing for now... and was able to get enough clearance to get the engine back into the truck for mock-up.

A good side profile to show how much deeper it is sitting. I don't exactly know where the "stock" location is relative to this, but the forwardmost exhaust port is about 3" behind the centerpoint of the two mounting bolts that held the stock engine crossmember at the top of the framerail.

It certainly looks like it's sitting deeper into the cowl than it used to!!

EDIT: Reference Pic with old 396... exhaust port is centered between two crossmember bolts (you can just barely make them out in the photo)

Does anyone have a reference measurement from the front face of the engine block, or from the harmonic damper clearance to the frontmost engine crossmember ( the "V" shaped one closest to the radiator)??

 

[4X4HIGH]

You would be better off getting a measurement from a motor mount bolt hole since the front of a BBC is longer than a SBC, of course unless someone with a BBC in the stock location gets the measurement you're looking for.

 

[Greg72]

2008.05.23 - UPDATE: 4 EXTRA INCHES!!!

It wasn't a trivial task, but I've managed to stretch the cowl to accomodate the 502BBC.

Here is a shot of the left-hand panel tacked into position.

The driver's side was more of a nightmare because the pedal assembly area has a special reinforcment plate for the brake booster. There is no simple way to cut away the 2" of clearance I needed, so I proceeded to cut about 20 spot welds to remove it completely.

The removed part is in the lower part of the photo. This part will need to be carefully reconstructed and customized to allow for the required mounting hole reinforcements, but also to clear the encroaching firewall.

Next I was able to tack the new cowl piece onto the driver's side. In this photo you can clearly see the 4" gap between the two pieces...this is effectively the "stretch" that was accomplished to widen the cowl in this area. That provides the critical clearance for the valve covers on the new engine.

Here is an inside shot to show what happened on the opposite side... I welded some temporary 4" sheetmetal spacers to hold the dimensions while I did the final trimming and fitment everywhere else. Since the cowl donor was from a '67 2WD truck, I had a few extra issues. The floorpans are slightly different in the way they transition from the floor angle to the vertical part of the cowl. It might have been easier in retrospect to use a "real" Blazer donor cowl.... maybe next time.

The payoff!!!

The photos don't really give a good sense of depth or clearance in the valve cover area, but if you study the previous photos you can probably see the improvement. In person, the extra room is quite obvious and it should be easy to remove either valve cover without issue now.

After looking at some older photos of the 396BBC and taking some new measurements, I've determined that my setback is now 3" deeper than it was before. What is more impressive is that previously I had the advantage of a 2" body lift to provide valvecover clearance, as well as all that sledgehammered sheetmetal on both sides.

There's still plenty of work left to get this all patched and finish-welded, but at this stage I've still got so much to solve with the driveline fitment, it doesn't make much sense to do that level of finish work yet...... plus I'm tired and hungry.

There's still plenty of weekend left...who knows what else I'll be able to get figured out!

 

[bigblock72]

WOOOOOOOOOWWWWWW, that looks way nice.

Keep the pictures coming, I'm getting bad ideas about my forthcoming big block swap. I've thought about doing the same thing on my blazer but didn't know how it would work out. All I know is I can't move the motor forward like I did on my K10, and I still need to get the valve covers off without having to raise the body. Glad to let you be the guinea pig.

 

[Yukon Jack]

That looks incredible, I'm totally impressed!!

Probably not as important now that you've got to this point, but here is a pic showing where my bbc is sitting using the stock sbc crossmember which is moved forward maybe 1/4". It's a huge pic so I'm linking it rather than posting the pic. http://yukon.b0xen.us/bbproject/p5060002.jpg

 

[Greg72]

2008.05.24 - UPDATE: REMOVING THE BRIDGE

Well the mock ups were pretty satisfying yesterday, but the only thing still incomplete was seeing the Atlas4 in position behind that TH400.

I still needed to resolve the issue with the output shaft being too long, so I decided to tackle that first.

I was really apprehensive about cutting it off without some sort of proper way to control the cut. I didn't want it to look all cheesy and crooked, so I just took my time and carefully marked the new dimension with my Dremel tool.

I very slowly cut into the output shaft and kept rotating it so that the cut would stay straight. It took about 30 minutes of tedious slow progress, but here is the end result.

I was even able to clean up the edges of the splines and put the factory chamfer back on it. Looks probably 95% as good as if I'd cut it on a lathe!!

Once that cut was completed, I was able to reassemble the entire driveline and prepare for installation. I still had to cut the seat "bridge" between the old transmission cover and the seat area. Since it is a stuctural element, I first had to weld in some diagonal bracing to the underside to keep the floors from collapsing.

Here's what I ended up with:

Pretty scary, eh? A few months ago, this would have terrified me.... now that gaping hole in my truck is nothing more than a means to an end. The confidence has certainly improved as I work my way through this process...

The payoff...... 26.5" of perfectly flat bellypan clearance with only a 38" tire!!! It's DEAD-SEXY!!

There is a price to pay for all that clearance underneath.... take a look at what I've still got to deal with inside now....

Ultimately, the seats are going to be mounted to seat cradles that are integrated into the roll cage, so I don't forsee any problems with clearance. The drivers seat is un affected, and the factory center console will be cut down vertically, so that the bulge underneath will be virtually invisible.

We'll see....

Next up..... real crossmembers!!

 

[bp71k5]

Where's the diagonal bracing under the seats? I must have missed that.

 

[Greg72]

Where's the diagonal bracing under the seats? I must have missed that.

It runs from the seat bridge area (just inside where the cut was made) diagonally down to the inside lower "C" of the framerail.

I had to come up with something that would support the floor, but wouldn't interfere with the driveline installation.

Based on where the front and rear output yokes ended up, I still have more cutting to do.

 

[bp71k5]

It runs from the seat bridge area (just inside where the cut was made) diagonally down to the inside lower "C" of the framerail.

I see, Is the bracing visible in the pictures? I had to cut the same area out on mine and am curious how you got bracing in there without getting in the way of the front driveline.

 

[Greg72]

I see, Is the bracing visible in the pictures? I had to cut the same area out on mine and am curious how you got bracing in there without getting in the way of the front driveline.

Brian,

What I did wouldn't be a good long-term solution. The bracing I used connects the body (above the body mounts) to the frame (below the body mounts). You can't build a hard mount between those areas...when the mounts flex it will tear the welds apart. There is probably a better permanent solution but if you span across the body mounts, it will need some kind of poly bushing incorporated to it.

 

[Burt4x4]

Hey Greg, here is a side shot of mine, just incase you need a second referance on the placement of your BBC

 

[Greg72]

Thanks Burt. Your photo seems to validate that the forwardmost exhaust port normally lines up perfectly between the two crossmember bolts...

I'd used that as my "reference point" and now have a measured setback of 3".

Unfortunaltely, the combination of the extra setback and the fact that the engine sits level (and lower) than normal, makes it impossible for me to bolt up headers yet.

I'm either going to have to do some substantial modifications to the upper frame rails, or cut and modify my headers...or build a set from scratch.

It's amazing how each change creates a snowball of "other" changes later on.

 

[Greg72]

2008.07.13 UPDATE! - ENGINE MOUNTS BEGIN...

The process of establishing new motor mounts has begun. My mind was a bit fuzzy from being out of the shop for so long, so it really took me a while to get back into "the zone" with my thoughts on how to attack this problem.

The hardest part by far is the fact that with the new driveline position, NOTHING is in it's original location, and there are NO mounts on any of the driveline parts to help establish a reference for alignment (either front-to-back or laterally). My thought was to re-use the factory engine crossmember as a starting point and see if it could be modified to work with the new setup.

Since it's impossible to install the factory crossmember with the engine in place, I had to remove the Atlas from the driveline, then yank the engine & tranny (for about the 20th time!) to get the lower cradle into position in the framerails. Once I put the engine into position, I quickly realized that the crossmember was interfering with the oilpan on the new 502BBC. This is probably a combination of my desire to mount the engine lower in the framerails than the factory did AND what I believe is a larger or different shaped oilpan than the factory 350SBC.

In the interest of making forward progress, I decided to mount the lower cradle from underneath the framerail instead of laying it on top of the lower "C" in the frame. This gives effectively about 1" of extra clearance to the oilpan. The challenge is that this creates about 1" gaps between the framerails and the boltholes on the crossmember. For now, I simply loaded those gaps with thick stacks of washers to take up the space...as you can see here:

The next challenge was choosing the proper location for the crossmember to sit (front-to-back) in the frame. Since the engine was relocated 3" further back into the firewall area, you'd think that the crossmember would also go about 3" back also. It doesn't. For some reason it lines up perfectly with the original crossmember frame holes!!! Don't ask me why, I'm still puzzling over that one. The nice part about that is that the lower crossmember will be lined up pretty squarely underneath the motor mounts and will give me plenty of options to fabricate the mount I'll need.

Strangely, the crossmember is extremely close to the oilpan in the area when the pan sweeps-up from deep to shallow. I think I will probably just grind down the lip on that side to gain maybe 1/8" of extra clearance. I will probably end up boxing up the crossmember once the design is finalized, so I'm not particularly concerned with strength. Here's a shot of that clearance issue with the oilpan:

The final part of the equation was to get the transmission pan raised up high enough to be safely between the framerails, with maybe 1/4" gap between the tranny pan and the skidplate that will eventually cover the entire bottom of the truck. The height of the transmission pan is a non-negotiable dimensional constraint, since I want it protected by a skidplate....so I had to solve the tranny height FIRST. Once I built a temporary tranny mount at the correct height, I put an anglefinder on the engine to see how "raked" it was. From there, I knew how tall the engine mount would need to be to get the engine back down to 0 degrees of rake. I don't want it "laid back" the way the factory does it.

Here is a shot of the motor mount bolted to the engine, with the round "puck style" motor mount. and a temporarly spacer. This is very close to it's final position in the truck. It need's to go maybe 1/4" to 1/2" lower than shown here...

And a shot from the driver's side.....

So that's where things are now. I have two more sets of those same rubber "pucks" that I will be using to create the transmission and transfercase mounts as well. I like the idea of using the same style of mount for the entire driveline. If I build the crossmembers correctly, they will be removeable and should allow for easier servicing of the truck later on.

 

[vtblazer]

Glad I was running late this morning so I could catch this update, things are goin' now!

 

[Greg72]

2008.07.17 UPDATE! - MOTOR MOUNTS COMPLETE!!

It took a while to get online (CK5 server troubles?) but here are the updates I'd hoped to post last night.

First off...."new stuff". $500 in new Grade-8 fasteners

I finally got tired enough of scrounging for bolts and proper fasteners, so I placed an online order for all sorts of bolts, washers and nuts in Grade-8 strength. Pretty much everything available between 1" long and 2" long (in 1/4" increments) and up to 9/16" diameter. I'd have bought more, but this stuff adds up quick!!!

I've got some Akro bins arrving tomorrow, so that each fastener can live in it's own spot. Should make my workshop a much nicer place to work, and remove a LOT of wasted time and frustration.

For the engine crossmember, I decided to re-use the factory one. There were two oval holes that needed to be welded up before I could drill out the new holes for the motor mounts. Here's a shot of one done, and one pending.

Here's a shot of the completed crossmember installed (with NEW hardware from my UPS delivery). The new motor mounts are installed at 19" centers.

Ultimately, the crossmember only ended up being moved back 1/2" from the original factory holes... but since the motor mount is a completely different design and layout, I ended up with an engine setback that is 3" deeper than the 396BBC that was removed.

Here is a shot of the final mounts bolted down, and the "money shot" of the engine centered and in place.

And here is a shot at about 11PM last night showing the overall space that I work in....

Next up: The transmission crossmember and Atlas crossmember!!