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1972 K20 6bt

168K views 302 replies 57 participants last post by  RiceColtB 
#1 ·
So, ive been a member for a while, but mostly just lurking around and absorbing some of the info on the site.

i decided to share what i've done so far to my 1972 K20.

rough sketch of the initial plan.

6bt and manual trans swap.

restore the rest of the truck and modify as necessary. or as i saw fit. sometimes the line between necessary and my imagination get pretty foggy.

Anyhow, the swap is a little more involved than that, but ill let the pictures explain that.

I was given this truck by my grandmother, as my grandfather asked her to do after he died. that was in 1997. i was 13 then. i had high hopes of making this truck into a mudracer that i could still drive to HS and be a total ladykiller with. hahaha.

i intalled a huge all spring skyjacker lift, later model one ton axles and bought some big old MT tires. then i was strait out of money. The ol' man had installed a 5.7 buick diesel and a np425 4 speed. so the idea for the current phase of the project has a little to do with making the truck grandpa wanted. mostly its because i wanted it but the idea was all grandpa.

so, it was a gutless turd to say the least, but i drove it for a while trying to scrape some cash together to build a decent BBC for it. eventually just before i took off for college, i yanked the 5.7 and prepped to build a 454. i got so far as sending the order for my internals to Jegs with the check. they biffed the order somehow and never sent the parts or cashed the check. then i was at college and the poor truck got stuck in the most convenient spot at the time. eventually it landed in my dads barnyard. there it sat for 8 years or so. i robbed the tires when i was building my M715.

on labor day weekend of 2011, i decided it was time to collect my truck and start doing something with it. i bought a nice new trailer and hitched up the wagons. by this time i live in SW colorado, so it was a little over 1100 mile trek.

i removed the big lift and installed a more civil, less high school 4" before it went on the trailer.

this is the day before the haul back to CO.


installed it in the garage at home and got to work. slowly

got the frame blasted. somewhere in here, i horse traded with a buddy to have my garage wired for the air comp and welder in trade for some sub frame connectors in his dart.
 

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#28 ·
If you have a keen eye for detail, you will have noticed that the a/c compressor has a new mount, and the alternator and water inlet have changed as well.

i ended up with an industrial set up. the compressor mount was a homemade job, but the water intlets and outlets as well as the alternator all changed industrial application stuff from some medium duty truck.

the alternator needed to move up, so i waterjetted a bracket for that from 6061 Al, 1/2" thick



this was to clear the fresh air inlet 100% so i can just use a nice clean mandrel bend without any obstructions.



also i needed to make a location for the tensioner. i milled this one out, but i may adjust it for a better belt fit. by milled i mean the holes, the rest was done handheld with a plasma.



here it is with the tensioner



and then i had you fooled into thinkin the front panhard was done, eh? well that was a lie. i finally made the mount for the axle end.

 
#29 ·
Looks pretty cool, even with the ugly mock up links



the front bags have an internal bump stop, but it is not intended to serve as the suspension bumpstop. so i had to make something for that. i knew that when i drew up the bag plates and had a landing pad cut in the lower plate for this reason. since i needed to decide on a final bump height to make a few things i need to design easier, made some bump stops. the cushion is an energy suspension poly unit. it threads into the aluminum part i spun on the lathe. that aluminum fits into the end of that DOM tube that is machined for effect only. then the set screw threads into the aluminum and seats against the counterbored clearance hole in the DOM. that means i have a replaceable part that i can use to adjust bump height if i want.

the DOM is notched for the framerail



 
#30 ·
so, to bring us pretty much to current,

the bump stops got fit and tacked in. looks like it all works good. i just need to gusset the plate under the bumpstop.





i have looked at the belt routing on the front, i need to see if i can trade the belt i have for a slightly longer one, or i may move the tensioner up a little if there isnt an appropriate belt to use.
 
#32 ·
Yes, Ryan, truly outstanding! You and Rube Bonnet would make one heck of a team. I don't know where you went to school but it sure was the right place! Excellent, thanks. An honor to your grandfather indeed...
 
#35 ·
Thanks! to be held in the same esteem as Mr. Bonnet is a high compliment! as for school, i wont say that bad word. I have had the opportunity to work with several talented people and learn a lot. I work as a kind of do all fabricator/welder, so i have access to some really nice tools at work.

This is a lot of work. Nice build.

Thing is probably going to weigh a lot when you get done too.
Thank you sir!

current well educated guess puts it in the area of 7K probably a bit more. i have a friend that is doing a truck almost exactly like this one, with the exception of a few differences that will make mine heavier. he has had his on a scale and i don't remember exactly what it was, somewhere in the 6500# range. he outweighs me by a little less than 100# so, that helps me too! eventually i will build a transfertank/toolbox for the bed. with the extra 500 or more pounds of fuel that will add, im sure ill be close to 8K. i consider that a win.

don't know what you're using for a tank sealer, but I can tell you I used the eastwood stuff on a fox body tank I notched to clear a mini tub and a sump I added out of steel, (should have used stainless) didn't want it to rust so I used the sealer, applied it exactly as instructed and it sat empty for months before I put fuel in it. don't know if the fuel I use was the cause (leaded c-16 race gas) or not, but it started coming off and clogging up my carb. ended up ditching it and making a tank from .090 alum. thought I was cool cause I got a Bridgeport 2 years ago, now everyone is waterjetting their shit! Sweet work man.
i picked a few out based on recommendations, but i have to look through my notes to remember exactly what they are. one was a really expensive 2 part epoxy that is supposed to be amazing, but is generally used on motorcycle tanks. the other was red something. supposed to be good as well, but not cheap either. i have really considered doing a tank from stainless, but it seems a bit of a waste to toss this one. i dont want Al particularly since its the back of the truck and could possibly get smacked. and in my line of work, ive seen far more Al tanks fatigue over time and leak than stainless. I really like welding aluminum so it was hard to convince myself not to go that route.

i would love to have my own bridgeport! i was tossed to the wolves a few years ago when it comes to machining. they really needed help on a project and i got the ol' trial by fire education. turns out i am pretty decent with it, and now i drive myself nuts thinking of ways to machine stuff. i just wish i had a better understanding of G code and could program the CNC machines with more skill. all of what i do is manual. if i had the CNC down i would be making some real messes! i have talked to the machinist, i think he is on board for trying to cut a 6BT head for an individual runner intake. i have another p7100 engine that i am slowly planning and collecting stuff for to make a real fire breather out of.

the waterjet is really cool. especially with the 3d head. it can do stuff i would never have thought about before. but it is slower and for a lot of what i do, its unnecessary. so for a lot of my parts i just cut them on the plasma table. and if i need real precision the mill is always there. certain parts though, it saves A LOT of set up and measuring. just draw it up on the computer and print out an almost perfect replica in metal.
 
#34 ·
don't know what you're using for a tank sealer, but I can tell you I used the eastwood stuff on a fox body tank I notched to clear a mini tub and a sump I added out of steel, (should have used stainless) didn't want it to rust so I used the sealer, applied it exactly as instructed and it sat empty for months before I put fuel in it. don't know if the fuel I use was the cause (leaded c-16 race gas) or not, but it started coming off and clogging up my carb. ended up ditching it and making a tank from .090 alum. thought I was cool cause I got a Bridgeport 2 years ago, now everyone is waterjetting their shit! Sweet work man.
 
#36 ·
tonight, i picked up a different belt. it looks like a success. no need to redesign anything. it also turned out to be a really common ford application belt, as opposed to the more rare than unicorns PN i originally ordered. now i think ill return the belt to NAPA and get it off of Rockauto since its half the cost.

 
#39 ·
Thanks! there are definitely some fun toys at work.

as for school, i hope for your sake, that you didn't...




I was out of town all weekend, so nothing new has happened. i hope to be able to cut the engine crossmember out this week, and get that installed soon.

In the mean time, i got a little sidetracked. i need to reseal the engine and spiff it up a bit as well. i really didnt want to roll it around on the floor with the hoist. i started piddling around with an engine stand. its been designed and we are going to run it through the load simulator to see if it will be as bad to the bone as i hope. my goal is to support the engine from the flywheel end and be able to turn it.

i got started today by facing a length of 4"x.500" wall DOM. i need to order some oilite bushings and finish boring the ID for a nice press fit. i also picked up a 60:1 worm drive reduction box from a buddy who just had it laying around. for those unfamiliar, with worm gears, the output wont drive the input. that means that it will hold the engine at whatever point in the rotation you decide to stop. and with 60:1 reduction, it should be pretty easy to turn.

here are some teaser pics





this is the DOM with my meat club for reference.



and the gear box.

 
#41 ·
Thanks!

i think i ended up catching a kidney infection or something, i have been peeing strawberry koolaid all day. but i couldnt go home without a little time on the project. i ordered the oilite bushing last night. tonight i think ill order the 1045 bar stock. anyhow, i bored the DOM for the bushings



i also picked up this beast for the fuel system on the truck. i think i mentioned that i am in the gathering and planning stage of building my other p-pump engine. the goal is about 1k HP. that means i need to move a lot of fuel. i have been hearing less than good things about the air dogs lately and decided to circumvent any volume or reliability issues before they came up. this is an A1000 aeromotive marine pump. it moves fuel. its also huge.



i have a couple filter heads ordered as well. hope to see them soon so i can try to at least get an idea of the fuel system plumbing going
 
#44 ·
Thanks!

Hey, Ryan, please stay right on top of that infection and don't take chances. Some really serious flu going around that's KILLING folks right and left!
I took some garlic and cranberry juice last night, much better today.



got the chance to cut the beginning of a cross member cut out. Please excuse the general filth and clutter. i'm not proud of it.



this is a quick and dirty mock up.

 
#43 ·
Hey, Ryan, please stay right on top of that infection and don't take chances. Some really serious flu going around that's KILLING folks right and left!
 
#47 ·
Thank you!


The right equipment, and some real skill, sure do make a difference!!
I have to cut stuff out with a torch and grind on it to make it look halfways decent. I would never even attempt most of that build. Show quality for sure!
The equipment is a huge benefit for me. ive been trying to justify the expense of a small table here at home so i can get my parts without the wait. its made me impatient!



I got a box today with another piece of the fuel plumbing in it.

filter heads from Nicktane. really spiffy looking part and totally worth it compared the time it would take me to make my own similarly.





and with the enormous CAT fuel filter. i still have to do some ordering to get the water separator coming.

 
#46 ·
The right equipment, and some real skill, sure do make a difference!!
I have to cut stuff out with a torch and grind on it to make it look halfways decent. I would never even attempt most of that build. Show quality for sure!
 
#48 ·
i made some headway on the crossmember. i pulled the engine to make things easier. i will re-cut the rear mount tabs. i needed to adjust things a little and they could have worked, but for five minutes on the computer and 2 bucks worth of material, ill just make them again.



i got it pretty close. didnt have much space left to work with.

 
#49 ·
revisited the rear crossmember bracket. revision was a home run so i burned it in.



the crossmember mounts are also the hard point for the rear set of engine mounts.



i also received a box with my fuel water separator and two spares inside. i opted for the slightly longer part number and it matched the cat filter just about right. not that it matters, but it satisfies my neurosis.

 
#50 ·
Wow man. Beautiful work! No corners cut, simply amazing. I'll be following this one drooling, waiting for the day I finally get to scratch my itch of 4bt in my 89 burb. It won't be nowhere near the class that your taking this truck to though. Again, simply amazing man.
 
#54 ·
Ah, a zoner! that old jeep is still kicking too. i may be hacking into that thing again when i get the chevy done. ive considered selling it, but it sure is fun to drive. just found an 8100 vortec on CL that i keep thinking about buying for it...

grandpa was a crafty old devil. i'd like to think i got some of his abilities helping me out right now. that man never said no to any problem. just scratched his head until he got it figured out. I was always impressed with how his work came out too. i always tease my dad that talent skipped a generation... he is a DIY sort to, but a little more "hack" than i prefer. haha
 
#55 ·
i did finally get this cut out and tested. i need to sand a slight amount off the bushing tube and the sleeves so the bushing is less tight in the mount. a little more wiggle room will help these go on a lot easier in the future. they arent the prettiest thing, but i wanted to use heavy material here due the longer reach out and the overhang of the block plate.



 
#56 ·
i melted the mounts together. these mounts are big and give me a solid landing pad for the turbo support and on the other side i need to fab a rear support for the hydraulic pump and air compressor on the other side.



i also yanked all the stock lift pump and fuel filter off the engine. i'm going to have to start thinking about fuel filters and lift pump mounts soon and it was in the way anyhow.

 
#57 ·
Sweet build! Do you know what the gpm and pressure is on your power steering pump? I am using an air compressor/power steering pump from an F600 bus chassis for my 86 chevy crew cab build and my power steering pump specs are 4 gpm and 2200 psi. I talked to a guy that builds hydroboost units and he says they require 2-3 gpm and a max of 1600 psi. It should be easy to reshim the pressure relief valve on the pump to get it down to the 1600 spec but I am a little comcerned about the 4 gpm issue, worried about heat buildup cause of the pump being too big for the rest of the system. Have you researched this with your setup? Will it be a problem?
 
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