chappy78
Full Access Member
- Joined
- Aug 22, 2019
- Posts
- 79
- Reaction score
- 114
- Location
- Seattle Area
- First Name
- chappy78
- Truck Year
- 1978
- Truck Model
- K20
- Engine Size
- 350
Hi Folks,
I'm a fairly new member and wanted to introduce myself and share a little about the build of my 1978 Chevy K20. I'm an enthusiastic hobbiest and I've built a vintage 4x4 every decade for the last 30 years. I'd been without a project for a while and earlier this summer this old blue machine followed me home. It’s a fleet-side Hawaiian Blue truck and is equipped with the original LS9 350 c.i. V8, SM465, and NP205. It’s a local truck originally sold by Brooks Biddle Chevrolet in Bothell, WA. In addition to the 350 V8 it was optioned with power steering, dual tanks, AM radio, 7.50-16D tires, and painted rear step bumper. I bought this truck with 67k original miles for a fair price this August from a young man who was moving out of town. I’m intending to use the truck primarily to tow my snowmobile, and for camping and exploring in the mountains in the summer, plus general utility use on the weekends.
Projects Completed:
Since I've owned the truck I've focused on getting the truck running well and riding smooth.
Under the hood I've overhauled all of the systems by replacing of the accessories, hoses, vacuum lines, belts, plugs, wires, etc with new AC Delco pieces. (I'll post part numbers for all of those soon.)
The stock springs and shocks were worn out so I installed a Tuff Country 2.5" spring set P/N 12721K and set of Bilstein 5125 shocks (2 ea. P/Ns 33-185590 and 33-186542) from SDTruckSpring.com. While I was at it I replaced the shackles with heavy duty, greaseable pieces from Offroad Design (front P/N GU37010, rear P/N 38015). They came with new bushings which I put in at the same time. The tires and wheels are updated, too. I put on a set of Wheel Vintiques 8" wide x 16" diameter 82 Series (P/N 82-680804) from Summit Racing mounted with 285/75R16 Cooper Discoverer M+S (Item# 10605) from Discount Tire. This setup is working great but the truck is tall and it takes a big jump to get in, especially for my petite lady. Between the tires and the lift I gained a little over 6” at the fenders. I suspect the springs will settle a bit.
I wasn't pleased with the cold nature or performance of the stock QuadraJet so I installed a Holley Sniper EFI (P/N 550-869) with a Holley Hyperspark ignition (P/N 556-151), coil (P/N 556-152) and distributor (P/N 565-300), all from Summit. I had never installed an EFI system before it was quite a challenge for me. One of the main challenges was deciding on a fuel delivery system, especially because I couldn't figure out how to deal with pumping fuel from my dual tank system affordably. In the end I chose to install an Edelbrock fuel sump system (P/N 36031) that I also sourced from Summit. I'm not sure I made the best decision to go with with the fuel sump but for now it's working and I'm going to keep it as it is. I will change in the future if necessary and as my budget allows. The EFI has been excellent, especially for cold starts and I’ve seen about 2 mpg improvement in fuel efficiency.
Projects in Work:
I’ve just started the process of swapping the stock motor with a new Chevrolet Performance 5.7L L31R Vortec crate engine (P/N 12681431) from Summit. I hadn’t planned on a new engine but due to low compression in two cylinders combined with my desire for more power, I’ve bitten the bullet and I’m going “all in”. I had considered an LS swap but I wanted to keep it Gen 1 SBC original and the L31R was an excellent value for a 4-bolt main engine with the sweet Vortec heads. I'm installing the engine with a Chevrolet Performance dual-plane manifold (P/N 12496820) and roller camshaft (P/N 14097395) from the HT383 crate motor. I think this will be a good combination with the Sniper fuel injection. I’m also making what I hope will be a good exhaust upgrade with some modified exhaust manifolds Products (P/N 192X-G) from Brzezinski Racing. I didn’t want to deal with headers and these seem like a good compromise between performance and ease of installation. Using their gasket-less pipe kit (P/N 193-G), the log-style manifolds will mate up to the Dynomax dual 2.25” system (P/N 89003) that I’ll install with two Dynomax Super Turbo Mufflers (P/N #17731) and an H-pipe kit (P/N 642022) from Summit.
The current fuel setup uses the stock mechanical fuel pump to feed the Edelbrock fuel sump. I’ll have to replace it with an electric pump near the dual tank switch since my new L31R Vortec engine has no mechanical fuel pump provision. I chose a Sniper 96 GPH, 7 PSI unit (P/N 80000100) that I’ll install with a Painless Wiring relay (P/N 50102). When it’s all done I plan to have the EFI professionally dyno-tuned by a local shop to make the most of the new powerplant.
Before I install the new engine I’ll replace the clutch with a Centerforce clutch kit (P/N KCF52356) mounted on a Chevrolet Performance flywheel (P/N 14088648). It was a chore to decide which clutch kit but the customer support people at Centerforce helped a lot. The kit includes everything except a new clutch fork and pivot ball stud that I picked up from NAPA (Dorman P/Ns 14550 and 14556, respectively).
With the engine out I’ll also upgrade the engine bay wiring with a kit I sourced from American Autowire (P/N 510347). I’ll install two elements of that kit, the engine harness and front light harness and wire up a set of PIAA halogen auxiliary driving lights (P/N 4062) picked up from Amazon.
The last big upgrade I’ll do in conjunction with the engine swap is to replace the current cheap aluminum and plastic radiator with a new brass and copper 3-row cross-flow OEM reproduction unit (P/N 382014) I bought from Summit. I want to take advantage of the Sniper EFI’s fan control feature so I’m upgrading from the mechanical fan to a dual 12” electric fan unit from Spal (P/N 30102130) hooked up to two of their pig-tails (P/N PT15300027) and relay wiring harness (P/N FRH-HO-KIT).
My indoor project when I'm not working on the engine swap is new dash panel with VDO Vision Black gauges that I'll probably do a separate write up on.
Future Projects:
Once the engine swap is complete and I replenish my project fund I’ll freshen up the interior with a new seat cover, and new foam with heating elements for heated seats, a new dash pad, and I’d like to put in a modern stereo as well as upgrade the dash harness with the balance of the wiring kit I bought from American Autowire. For the exterior I plan on replacing the front fenders, inner fenders, and doors rather than repairing the areas that have rusted through. I’ll get some aerosol cans mixed to match the the faded paint and spray some color on the new parts sheet metal. I like the patina and don’t want to be too fussy about the exterior so I’ll try to keep the current look intact as much as possible. I’m going to have to learn some patina preservation techniques. I’ll probably paint the bumpers black, too. I’ve read the rear step bumper isn’t compatible with the aftermarket tow hitches that are available now so I’ll be looking for a standard bumper if I can’t make the hitch and my step bumper work together.
For the drivetrain I’ll keep the rest stock except an upgrade to Warn premium hubs (P/N 20990). I’d love a NV4500 for the overdrive someday.
So there it is! That’s my project. I’ll share more as I proceed and hopefully someone can gain from my experience and the product information.
chappy78
I'm a fairly new member and wanted to introduce myself and share a little about the build of my 1978 Chevy K20. I'm an enthusiastic hobbiest and I've built a vintage 4x4 every decade for the last 30 years. I'd been without a project for a while and earlier this summer this old blue machine followed me home. It’s a fleet-side Hawaiian Blue truck and is equipped with the original LS9 350 c.i. V8, SM465, and NP205. It’s a local truck originally sold by Brooks Biddle Chevrolet in Bothell, WA. In addition to the 350 V8 it was optioned with power steering, dual tanks, AM radio, 7.50-16D tires, and painted rear step bumper. I bought this truck with 67k original miles for a fair price this August from a young man who was moving out of town. I’m intending to use the truck primarily to tow my snowmobile, and for camping and exploring in the mountains in the summer, plus general utility use on the weekends.
You must be registered for see images attach
Projects Completed:
Since I've owned the truck I've focused on getting the truck running well and riding smooth.
Under the hood I've overhauled all of the systems by replacing of the accessories, hoses, vacuum lines, belts, plugs, wires, etc with new AC Delco pieces. (I'll post part numbers for all of those soon.)
The stock springs and shocks were worn out so I installed a Tuff Country 2.5" spring set P/N 12721K and set of Bilstein 5125 shocks (2 ea. P/Ns 33-185590 and 33-186542) from SDTruckSpring.com. While I was at it I replaced the shackles with heavy duty, greaseable pieces from Offroad Design (front P/N GU37010, rear P/N 38015). They came with new bushings which I put in at the same time. The tires and wheels are updated, too. I put on a set of Wheel Vintiques 8" wide x 16" diameter 82 Series (P/N 82-680804) from Summit Racing mounted with 285/75R16 Cooper Discoverer M+S (Item# 10605) from Discount Tire. This setup is working great but the truck is tall and it takes a big jump to get in, especially for my petite lady. Between the tires and the lift I gained a little over 6” at the fenders. I suspect the springs will settle a bit.
You must be registered for see images attach
I wasn't pleased with the cold nature or performance of the stock QuadraJet so I installed a Holley Sniper EFI (P/N 550-869) with a Holley Hyperspark ignition (P/N 556-151), coil (P/N 556-152) and distributor (P/N 565-300), all from Summit. I had never installed an EFI system before it was quite a challenge for me. One of the main challenges was deciding on a fuel delivery system, especially because I couldn't figure out how to deal with pumping fuel from my dual tank system affordably. In the end I chose to install an Edelbrock fuel sump system (P/N 36031) that I also sourced from Summit. I'm not sure I made the best decision to go with with the fuel sump but for now it's working and I'm going to keep it as it is. I will change in the future if necessary and as my budget allows. The EFI has been excellent, especially for cold starts and I’ve seen about 2 mpg improvement in fuel efficiency.
You must be registered for see images attach
You must be registered for see images attach
Projects in Work:
I’ve just started the process of swapping the stock motor with a new Chevrolet Performance 5.7L L31R Vortec crate engine (P/N 12681431) from Summit. I hadn’t planned on a new engine but due to low compression in two cylinders combined with my desire for more power, I’ve bitten the bullet and I’m going “all in”. I had considered an LS swap but I wanted to keep it Gen 1 SBC original and the L31R was an excellent value for a 4-bolt main engine with the sweet Vortec heads. I'm installing the engine with a Chevrolet Performance dual-plane manifold (P/N 12496820) and roller camshaft (P/N 14097395) from the HT383 crate motor. I think this will be a good combination with the Sniper fuel injection. I’m also making what I hope will be a good exhaust upgrade with some modified exhaust manifolds Products (P/N 192X-G) from Brzezinski Racing. I didn’t want to deal with headers and these seem like a good compromise between performance and ease of installation. Using their gasket-less pipe kit (P/N 193-G), the log-style manifolds will mate up to the Dynomax dual 2.25” system (P/N 89003) that I’ll install with two Dynomax Super Turbo Mufflers (P/N #17731) and an H-pipe kit (P/N 642022) from Summit.
You must be registered for see images attach
The current fuel setup uses the stock mechanical fuel pump to feed the Edelbrock fuel sump. I’ll have to replace it with an electric pump near the dual tank switch since my new L31R Vortec engine has no mechanical fuel pump provision. I chose a Sniper 96 GPH, 7 PSI unit (P/N 80000100) that I’ll install with a Painless Wiring relay (P/N 50102). When it’s all done I plan to have the EFI professionally dyno-tuned by a local shop to make the most of the new powerplant.
Before I install the new engine I’ll replace the clutch with a Centerforce clutch kit (P/N KCF52356) mounted on a Chevrolet Performance flywheel (P/N 14088648). It was a chore to decide which clutch kit but the customer support people at Centerforce helped a lot. The kit includes everything except a new clutch fork and pivot ball stud that I picked up from NAPA (Dorman P/Ns 14550 and 14556, respectively).
With the engine out I’ll also upgrade the engine bay wiring with a kit I sourced from American Autowire (P/N 510347). I’ll install two elements of that kit, the engine harness and front light harness and wire up a set of PIAA halogen auxiliary driving lights (P/N 4062) picked up from Amazon.
The last big upgrade I’ll do in conjunction with the engine swap is to replace the current cheap aluminum and plastic radiator with a new brass and copper 3-row cross-flow OEM reproduction unit (P/N 382014) I bought from Summit. I want to take advantage of the Sniper EFI’s fan control feature so I’m upgrading from the mechanical fan to a dual 12” electric fan unit from Spal (P/N 30102130) hooked up to two of their pig-tails (P/N PT15300027) and relay wiring harness (P/N FRH-HO-KIT).
My indoor project when I'm not working on the engine swap is new dash panel with VDO Vision Black gauges that I'll probably do a separate write up on.
You must be registered for see images attach
Future Projects:
Once the engine swap is complete and I replenish my project fund I’ll freshen up the interior with a new seat cover, and new foam with heating elements for heated seats, a new dash pad, and I’d like to put in a modern stereo as well as upgrade the dash harness with the balance of the wiring kit I bought from American Autowire. For the exterior I plan on replacing the front fenders, inner fenders, and doors rather than repairing the areas that have rusted through. I’ll get some aerosol cans mixed to match the the faded paint and spray some color on the new parts sheet metal. I like the patina and don’t want to be too fussy about the exterior so I’ll try to keep the current look intact as much as possible. I’m going to have to learn some patina preservation techniques. I’ll probably paint the bumpers black, too. I’ve read the rear step bumper isn’t compatible with the aftermarket tow hitches that are available now so I’ll be looking for a standard bumper if I can’t make the hitch and my step bumper work together.
For the drivetrain I’ll keep the rest stock except an upgrade to Warn premium hubs (P/N 20990). I’d love a NV4500 for the overdrive someday.
So there it is! That’s my project. I’ll share more as I proceed and hopefully someone can gain from my experience and the product information.
chappy78
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