Not sure where to go with my project from here... (back from hiatus and motor swap)

[chevy72blu]

Hey folks, it sure has been a while since I was a regular here. This will be a somewhat long winded, rambling post.

Leaving for college left my '72 in my folks garage for nearly 5 years unloved and totally neglected. Before leaving I (stupidly) sold off the cherry 383 that I had built for it in lieu of a gnarly BBC that I built over a year or two. I had big dreams of getting more seriously involved in bracket racing and like most 17 year olds, cared about nothing other than my 1/4 time. Shortly after I ran out of funds to finish the project and its sat for years at about 80% complete. Motor has still never run, and it breaks my heart every time I see it.

Fast forward to today and I am married, have my degree, stable employment, and just purchased my first home. My most recent DD blew a motor (it was cheap junk from craigslist to get me through college) and here I am sharing a car with my wife for the time being. I have the time and funds to finish the truck, but I find myself wishing for good mileage and reliable transportation rather than burning up the strip. Dont care about impressing my buddies, dont care about burnouts, dont care about having the most standout build. Funny how priorities change in just a few years, hmm?

I plan on pulling the BBC and shelving it for the next few years. Eventually I am going to want to go fast again and when that happens, I'll build a dedicated track car with it. I could sell it to fund more work on the truck, but I wont get a fraction out of it of what I put in.

So, if you were to take a good looking truck with a sound drive train and drop a new motor in, which way would you go? I am aiming for 14-15 MPG city and 18-20 high way, along with solid reliability and a simple swap. It'll be mated to a TH350, stock converter, and 3.73's (may swap out later or go to a 700r4 trans). 250+ hp will do me fine.

I have been reading about the 5.3 swaps and while they sound nice, I have zero clue what I am doing with electrical. Honestly, it took a long time to admit it because I faked it for a long time... But, I am worried about getting overwhelmed and abandoning it like I have previously.

I already installed an electric fuel pump and regulator, so I am considering going to a vortec head roller crate. Specifically, this one:
http://www.summitracing.com/parts/NAL-12530282/

I understand that these are only 255 hp motors, but rollers are a snap to change later. Would the higher compression and more modern heads result in better fuel economy?

Or, I K.I.S.S and go with a Gen I flat tappet
http://paceperformance.com/i-5146377...te-engine.html


I pretty much need to start over with brackets, so I would appreciate some advice on which way to go. For the first time in my life I would like something with instructions... . I've done enough junkyard diving for a while. Driverside 1 wire alternator, driverside P/S pump, passenger side AC Compressor.

I'll likely run another Edel 1406 carb on a cast iron intake (I have one laying around), and go back to the stock ramhorn manifolds to avoid the constant header leaks.

Thank you for your help!


Pics for your time, from back in her hey day.

[72 tigger]

Welcome back! I think you're on the right track when you mentioned the 5.3. I think you would be happy with the mileage & driveability of a modern 5.3 EFI with a OD trans. Hope it works out!

[chevy72blu]

Originally Posted by 72 tigger

Welcome back! I think you're on the right track when you mentioned the 5.3. I think you would be happy with the mileage & driveability of a modern 5.3 EFI with a OD trans. Hope it works out!

Thanks 72 tigger! Have you done the swap? I have done some more reading on it but it still seems a bit overwhelming. I'm a wrench and weld kinda guy... Running EFI + ECM, etc seems daunting. I'm still open to the idea if the difference in mileage is that significant.

What kinda MPG are you folks getting out of the 5.3s?

[davepl]

If its in your budget, get an LS crate motor -with- the factory ECU. If you've been at college for 5 years you can hook up power and ground :-)

The cheaper option, one you refer to above, is the 5.3LS. But get a "Take out" motor from a wrecker (or engine reseller, there are numerous ones online) that includes the factory computer, accessories, belt drive, and so on. Because you have a truck you have a great advantage in that you can run the truck intake, which is taller and doesn't fit under many car hoods, but its far cheaper and makes nice torque.

Get a book on LS swaps, there are half a dozen on eBay. As someone with numerous big blocks, if I was looking for driveability and mileage I think an LS managed by the factory computer can't be beat.

Did I mention factory computer a few times already? Keep in mind they have literally HUNDREDS OF THOUSANDS of hours into driveability and tuning. There's no way you (or I) can approach that with a laptop and aftermarket computer.

If you're using a factory LS harness you really won't be doing much wiring yourself. There's power, ground, and connectors. And from what I remember all the connectors are unique, so its hard to get wrong. Again, this is for a complete engine... if you get a partial and have to complete it on your own, it's engineering time.

I think the hardest part would be getting the vehicle speed sensor, but Summit sells a number that bolt a little pickup by the driveshaft. But its all been done a thousand times before, so you can probably lean on the knowledge of LS users online quite a bit.

[JointTech]

hahaha. you are old. welcome to the club.

[Dingfodgy]

Welcome back! Nice to see you didn't completely abandon the project. It is funny how priorities change with maturity-huh? As mentioned above modern LS power with an overdrive auto or 6-speed manual is probably the best combo to use for reliability and efficiency. If you get the complete powertrain as a take-out unit, you're gonna have to send the ECU out to have some uneeded algorithms removed. Most times they come back with a simple 4-wire hookup...I'm not even college edumacated and could probably figure that out! However it's not just the motor swap there is also fuel and cooling system upgrades that will be needed. Nothing remotely complicated or technical just some time and $$$.
Now get after it and let us know how it goes.

[chevy72blu]

Thanks for the replies!

If anyone else has taken a long break from their truck, you surely understand how exciting it is to jump back in.

I have been researching the swap for hours and its getting a little less intimidating over time. I planned on spending $2.5-3k for a crate 350 and accessories, so the 5.3 isnt necessarily out of the question if I can find a good candidate.

My main concerns are the fuel issues (still have the stock tank behind the seat) - high pressure and return, and actual mounting. Electrical doesnt seem as scary knowing that there are lots of vendors looking for my $$ to get it done. I still have a ton to learn about the various models (DBW, etc)... In the mean time I will keep my eye on a 5.3ls/4l60e and read as much as I can. Lots of people on here have build threads that make it look much easier than it actually is...

[mcmlxix]

Originally Posted by chevy72blu

Thanks for the replies!

If anyone else has taken a long break from their truck, you surely understand how exciting it is to jump back in.

I have been researching the swap for hours and its getting a little less intimidating over time. I planned on spending $2.5-3k for a crate 350 and accessories, so the 5.3 isnt necessarily out of the question if I can find a good candidate.

My main concerns are the fuel issues (still have the stock tank behind the seat) - high pressure and return, and actual mounting. Electrical doesnt seem as scary knowing that there are lots of vendors looking for my $$ to get it done. I still have a ton to learn about the various models (DBW, etc)... In the mean time I will keep my eye on a 5.3ls/4l60e and read as much as I can. Lots of people on here have build threads that make it look much easier than it actually is...

You can use an EFI Blazer/Suburban tank under the bed. There was one on CL here in town. HERE

I know some one in Henderson who has a set of 2WD LS mounts that he may not use. He also has a 4x4 and didint realize they wouldn't work.

If your're going LSx, skip the TH350/700r4. The factory ECM will also control the transmission.

You can rework the factory harness, it looks like a bunch of work but not impossible. If you dont get a harness (like me) there are other vendors that will build a new one from scratch..

[72 tigger]

Another thread on the 5.3 topic is: What's your impression of a 5.3L LS motor in these trucks? Sorry, I don't know how to tag it so that you could just click on it- hope it helps