1973 Chevy C20 5.3 Turbo Build
Hello everyone, I'm new to the site and thought I would post some info on my truck build. Hopefully this can help some others with information as I've learned a lot online here from the forums as well.
Here goes - Starting truck is a 1973 Chevy C20 Cheyenne truck. Old motor was 454 and had a TH400 trans. This truck is in decent shape and already had some restoration work done to it. But the 454 and TH400 were VERY tired... The 454 was an ox of a motor but used oil like a 2 stroke. I contemplated a basic rebuild of it (which is easy to get 500hp) but I'd still have a gas guzzler of a motor and a highway unfriendly 3 speed auto and 3.73 gears.
So - I purchased a salvage 5.3 motor (80k miles) from a 2002 Suburban. Also I decided on 1996 4L80E trans for it. Lastly, I wanted it to be turbocharged as I'm very jealous of the ridiculous power people are making with very simple combos. My end goal is not one of full on drag race, but rather have daily driveability (w/AC), pull down "reasonable" fuel mileage, and have enough power to stay ahead of the modern stuff on the road, if not embarrass them...
Here is the current parts list on the truck -
5.3 LS engine (2002 vintage)
4L80E trans (1996 vintage)
Revmax 10.5 full billet converter (2400)
Nook & Tranny Flexplate (sweet unit, all new and allows the use of 4L80's behind the LS motor, uses 6 bolt converter mount and the starter motor teeth are welded on correctly to use the original 5.3 starter motor.)
Dirty Dingo LS engine brackets for my year of truck - Keep in mind when using these for this application that in order to use the LS motor factory AC compressor location, the engine MUST be positioned in the brackets as far forward (to the radiator) as possible. If you push the motor back (towards the firewall) it will cover up the mounting location. It will also further complicate the trans mount location -more on that below.....
Just Chevy Trucks Turbo kit - designed for newer LS motor Chevy trucks but I decided to try it out on my application. Physically it fits, but there are modifications needed. more on that below...
GT45 Turbo - DNA Motoring. A little big for my intended use, but it seems to be the best (low cost) turbo that people are going with. It's T4 mount, so in the future I can always play with swapping if needed.
PSI Performance PCM tuning and wiring harness- Everything is new and sweet. Almost the cost of paying someone to modify your old stuff, but without the WAIT time! Nice company.
Griffen Radiator - factory radiator is too big and in the way of the turbo intake. Went with a 19" unit that is designed for 600hp and has the LS outlets on the passenger side.
One of the problems I encountered with this swap is the trans member mounting location. With the Dirty Dingo mounts and the 4L80E trans, it places the rear mount about 1.5" too far rearward. You have to move the stock cross member back and re-drill the frame. It's a huge bummer because this particular truck has upper brackets also so you have to re-drill the frame on the upper support and lower. Oh and the bolts on the upper, are NOT accessible without lifting up the bed! Nice... Also this swap requires the shortening of my driveshaft. It's a 2 piece unit so I'll have to figure out the best way to measure on this.
The other problem I encountered was with the factory radiator. With the turbocharger installed, the air intake is about 2 inches from the upper hose outlet. That's a no-go... So to keep the turbo arrangement as is - i had to order a special 19" width Griffen unit to clear the turbo intake. Sweet unit, but the price tag on this project keeps going up!
The goal for me is to make as much power possible using the stock cam and long block. Valve springs are in it's future, but I'm really trying to stay away from a lopey cam. And honestly this thing should make enough power to keep my rear tires from hooking anyway, so another 100hp won't necessarily help matters here... :)
I'm having trouble posting build pics to this thread. I have pics in my profile if anyone is interested. I will put a few more out there later with more updates.
Trying hard to get it fired up in the next few weeks. I will get the bugs worked out on things. Then I will swap to 60lb injectors, trailer the truck to the muffler shop for down pipe work. Then off to a dyno/tuning shop for set up. That will be the fun part.
More to come....
