5.3 into a square -- questions

[kipps]

Truck is a 1987 v20 pickup, used for general farm errands and personal transportation, and likely a 12k cattle trailer in the future.

Truck tbi engine is rather tired, has never ran well, and is having numerous wiring issues. Faced with learning the entire tbi system, rewiring it, and likely replacing the engine, I think I'd better start with a better engine.

Donor is a 2010 tahoe that was rolled a couple weeks ago, and is available in its entirety for scrap price.

Engine will be attached to existing sm465 manual transmission, using a 6.0 flywheel and stock clutch. Already have a new stock radiator in the truck, so will use that.

Can I install the 2010 fuel pump into the 87 tank?

Is there a practical option for a engine driven fan, or should I plan on electric fans?

Can the old-school clamped fuel hoses handle the fuel pressures required?

Will I in any way regret using a stock 5.3 over a fully rebuilt 350 tbi?

[BR3W CITY]

The fuel hoses MUST be changed out. You'll need all high pressure EFI hose, or braided line, and the appropriate clamps. The difference in pressure between a carb/tbi setup and LS rail pressure is a full order of magnitude.

No you won't regret it.

[mongocanfly]

I contemplated keeping my sm465 but opted for a nv4500..no regrets for the o.d.
you could use the fuel pump as you asked but you can also use a inline walbro 255 and a vett filter/reg...much easier setup...
just use elec fans...
no, on old school hose clamps. .you'll be running 60+ psi on fuel pressure. ..don't take the risk..
will you regret it? I doubt it..

[87Skier]

Why not swap the transmission too? I know a lot of people prefer manual transmissions, but it shouldn't take much to convert the transfer case in the truck to mate up.

The 6L80 uses the same shaft spline as a Turbo400/4L80E, which were mated to the transfer case in that truck. Around 1980 the 10 spline shaft in the SM465 was converted over to a 32 spline (same as Turbo400/4L80E), and later ones also got the round pattern would should be the same as the one on the 6L80. Just thought I would mention that option.

If that tahoe has a 6L90, you would have to have a transfer case with a 29 spline input, the Dodge NP205 had this.

I think the 5.3 will make the same if not more torque and a lot more horsepower. Especially if your tbi is really worn and the 5.3 is still in decent shape.

[kipps]

I prefer a manual, so that takes preference. Also, not running tranny cooler lines, much simpler wiring, and not changing out the steering column is a big plus.

Exhaust question -- It appears I have two options. #1, keep the sm465 and external slave as is, and buy a different drivers side manifold. It will likely take a bit of work to massage the cat in around the slave. I'll be paying an exhaust shop to do that, so that's more dollars. #2, spend $350 for an internal slave, and use the existing manifold and much of the existing collector pipe/cat assembly. This brings with it the hassle of replacing the internal slave if it fails, but makes for a much cleaner exhaust installation.

Which route would you go?

[87Skier]

Originally Posted by kipps

I prefer a manual, so that takes preference. Also, not running tranny cooler lines, much simpler wiring, and not changing out the steering column is a big plus.

Exhaust question -- It appears I have two options. #1, keep the sm465 and external slave as is, and buy a different drivers side manifold. It will likely take a bit of work to massage the cat in around the slave. I'll be paying an exhaust shop to do that, so that's more dollars. #2, spend $350 for an internal slave, and use the existing manifold and much of the existing collector pipe/cat assembly. This brings with it the hassle of replacing the internal slave if it fails, but makes for a much cleaner exhaust installation.

Which route would you go?

I'm not too familiar with LS swaps in square bodies, but in the 72 and older the stock exhaust manifolds don't fit. I would go with option 2 if you are sure the manifolds fit and convert to internal slave.

For option 1, I would also run matched manifolds. There's the common Hooker LS cast manifolds and the CTS-V.

[izzy_Britton]

The 2010 Camaro exhaust manifolds fit without the need to notch the frame.

I am pretty sure that if you used the camaro manifolds and the truck cats, but moved the cats back a bit the only thing that you would need to change would be the length of the o2 sensor wires, the placement of the cats further back on the exhaust to clear your slave shouldnt screw with the o2 readings.

You could use your existing fuel sending unit in the tank just change out the in tank pump, you have an 87 so it already has the anti-slosh basket in the bottom of the tank. if it is a single tank truck you would just need to install some earls fittings and high pressure fuel line, quick n dirty. if it is a dual tank set up, same difference, again you should already have the high pressure tank switch. the inline corvette filter and regulator is a simple setup with single or dual tank. Here is some more info - THIS SET UP

you COULD run an engine driven cooling fan, just install a 99-2005(ish) water pump which has the provisions for the threaded fan adapter and get a fan and fan clutch from a 99-05(ish) truck. This is a direct bolt on swap.

I think your going to have issues with emissions unless you plan to fully integrate the vapor recovery system and such. if your not worried about emissions you could ditch the cats and not worry about the slave being in the way. the cats are not necessary for proper function of the engine if removing emissions. But i have no idea how emissions testing is done outside the Kalifornia Communist Republic.

-Izzy

[BR3W CITY]

Originally Posted by izzy_Britton

But i have no idea how emissions testing is done outside the Kalifornia Communist Republic.

-Izzy

Usually someone stares at the car blankly from about 20ft away while checking their phone, then plugs in the obd scanner and goes back to their phone, then hands a passing slip, and resumes their distraction.

Our emissions tests are performed by $9 lube shop employees.

[NC_John]

Originally Posted by BR3W CITY

Usually someone stares at the car blankly from about 20ft away while checking their phone, then plugs in the obd scanner and goes back to their phone, then hands a passing slip, and resumes their distraction.

Our emissions tests are performed by $9 lube shop employees.

If you know the engine management software well enough (HP Tuners or the bosch platform) you can make ANYTHING pass a state emissions test (through the OBDII anyway). A friend of mine got a full blown road course car (with straight pipes) through a legit test. He said the garage that tested it could only laugh because they knew what was done (and give him his paperwork for the dmv). The computer thought it was looking at a stock engine.

[kipps]

More questions.

How important are matched exhaust manifolds? I have a complete set of trailblazer manifolds, and am planning to buy a driver's side '98 to '02 camaro manifold(to clear the slave cylinder). Will the mismatched manifolds hurt anything? The camaro manifold will have an o2 bung in the manifold itself. The TB manifold does not. Will the different sensor positions matter?

Is it reasonable to mount the obd2 port under the hood? It would potentially keep the wiring harness a lot neater.

This a fourth gen engine. Is there a cheap way to convert to drive-by-cable? Again, it would simplify the wiring harness considerably.

Keep in mind, this is a pretty basic truck. No AC, no cruise, no automatic, etc. If it's not essential to operation, I'm eliminating it. Since I'm not running circuits into the cabin for the above functions, it would be nice to continue the theme, and keep the engine harness out of the cabin altogether.

[BR3W CITY]

Mismatched headers will flow different amounts, so you'll have some imbalance between the the STFT/LTFT readings and your 02 readings. On a stock motor you can get away with it, but its not ideal. If the difference between the banks is high enough the computer may toss a code as it thinks something is wrong and attempts to correct.