5.3L GenIII /TH400 swap

[68fleetsidec20]

The 350 in my truck was on its last legs; the heads were cracked, valve seals leaking, cylinders heavily worn and pitted and it failed the emissions test misserably, so it was time for something new.
I picked up an almost complete 5.3L for around the cost of a low milage sbc. I decide to keep the TH400 as with my 30" tall tires and 3.08 gears I wouldn't be needing overdrive, although torque converter lockup would be nice.
Two days I pulled apart the front end of the truck and pulled out the tired 350

Yesterday I finished preping the engine and bolted it to the transmission using a spacer GM12563532 and new longer bolts GM12563533. The spacer and bolts are to make up for the shorter torque converter of the TH400. I had heard that the flexplate had bolt holes that would match up with the th400 torque converter, however I did not find this to be the case. Using the extra raised pads on the flexplate I carefully drilled holes to mount up with my torque converter. This seemed to work good.


I was then able to drop the engine in keeping the transmission in its stock location so that the shifter linkage and driveshaft would be uneffected. For the motor mounts I used common adaptor brackets and swaped the original trucks pedestle mounts side to side and 2 of the 3 bolt holes lined right up. The third one I will drill.
I test fitted the factor 5.3L exhaust manifolds and the drivers side fit with minor modification.

and the passanges side with a little more modification. The frame will need to be slightly clearanced as well. However If I not mistaken the 67's have wider frame rails around the engine then the 68-72s so it may not be an issue with other trucks.

The heat shields caused problems on both sides so I will leave them off for now, but the should fit with some modification.
I'll keep this thread updated with my progress, the plan is to have it finished by the end of the week.

[68fleetsidec20]

Today went a little slower then I was hoping for. I under estimated how much I needed to notch out of the frame to get the passengers side exhaust manifold to fit. but I did get it in eventually.

I then spent some time hooking up vaccum lines, linkages etc.

One item that didn't come with this engine was the starter, I went down to the parts store and they list at $450, I couldn't believe it. My cost was $275 but even that is like 3 times the cost of a sbc starter. And the starter bolts at $13 a piece, making me start to wonder if this Gen III thing is a good idea.

The rest of my day was spent on the fuel system. I converted the pickup for a return system.


and installed a low pressure pump.

I decided to run the fuel system on the out side of the frame rails as the inside is tight with the exhaust and brake lines.

Tomorrow I have to find a fuse/relay box get some adaptors for my fuel system and power steering and figure out the air intake. I guess I should have been more prepared, it might be tough to get this wrapped up this weekend.

[shifty]

I bought this setup, after seeing it installed in '68 short step's truck:

http://cgi.ebay.com/ebaymotors/1999-...9768QQtcZphoto

With that said:

Pros: It looks sweet and comes with everything you need.
Cons: You gotta move your battery to another location.

I am using a stock auxillary battery tray to move the battery to the passenger side of truck

Notes:

RE: your fuel line setup: Very creative. BE AWARE: you need to be able to put at least 50PSI to the fuel rail, make sure your pump can generate that. Your engine should have a regulator built into the rail if it's truck/newer.

Don't forget hose clamps be sure your fuel line can handle 50PSI pressure without blowing up

[shifty]

PS -

people ask "how much does this swap cost?!"

http://www.ls1tech.com/forums/showpo...&postcount=188

i went with a simple fuel system I knew would be adequate, one that would move the tank out of the cab. cost for a very modest kit (no frills) was over $1,000. this included the tank, pump, lines, fittings, filter/pressure regulator, pressure gauge, etc.

that post might be worth a read. Actually - that entire thread may be worth a read, i dunno.

[shifty]

PPS, then I quit posting.

The '98 Camaro/Transam stock manifolds fit without hacking the framerails - you used custom mount plates, so the hacking would simply be "less". using the ECE engine mounts ($250) with the 98 manifolds == no hacking the rails.

[68fleetsidec20]

Shifty; As I am using the stock unbaffled tank it is best to go with a low pressure pump, a small storage tank then a high pressure pump. This way even as the fuel sloshes around in the tank the engine will never lose fuel pressure. Hopefully tomorow you will see the rest of my fuel setup. As for hose clamps, they will be added I am just mocking everything up for now. Thanks for the link but I think I will just make my own system.

[68fleetsidec20]

Shifty; One recurring theme you might notice for this swap is cheap! My fuel system comes in under $200, new manifolds cost more money and fancy mouting kits are expensive. The end result my not look nearly as pretty as yours but should function just as well. When I finish I'll post a picture of the truck and you'll understand why "pretty" is not a big concern at the moment.

[gringoloco]

One small suggestion on your sending unit. Either shorten your return line, or bend it away from the pickup. I did a set-up like this (in a '67 Mustang I dropped a 5.0 and T-5 in) the same way as you, by soldering the return in place. If the return is right next to the pickup, you may have problems with aerated fuel being sucked up directly from the return line.

Keep us updated on the progress. I'm like you- I'd rather build it and save a few bucks than buy it. Bites you in the a$$ sometimes though, when it would have been cheaper/easier just to buy it. Oh well, that's all part of the fun...

-Chris

[68fleetsidec20]

Today I finished my fuel system (minus hose clamps) with my reserve tank, high pressure pump, lines filter, etc.

To quickly explain the external sump;
the top left line is low pressure fuel comming in
the bottom right is fuel going to the high pressure pump.
the bottom left is the return form the engine
and the top right is back to the gas tank.



I used the Russell quick connects to mate to the fuel rail


Then I took some time to start the wiring

Earlier I made use of the ECU pinout and removed all unnecessary wires from the harness such as transmission, EGR, etc. I must have pulled a third of the wires out which makes things a lot simpler. I'm not to happy how the main junction of harness is located right in the middle of the intake, so I'll probably take some time to reroute the wires to make them more hidden.

I also put the radiator support back on as well as many other missalanious things.

[68fleetsidec20]

57T210; Excluding parts runs, cleaning and painting the engine, and spending hours reading forums I probably only have less 35 hours into it and thats including the long day I put in today.

Today I went out looking for a fuse box and came up with this,

its out of a 1994 Grand Prix and seems to have everything I need and puts it in a nice package.

I tried to get some 4' aluminium bends for my intake but the local performance shop does't carry anything that size so Monady I'll get some 4" 304SS bends from work and fab up my intake. Untill then I bought a 90 degree plastic plumbing pipe and clamped it in.
The majority of my time today was spent on wiring. It was something I was looking forward to but once I got my game plan set up it went pretty smoothly. I managed to move the harness around so all the wires didn't sit right in the middle of the intake, instead tucking up around the backside. I got the majority of the wires soldered and heat shrunk into there respective locations and some just temporarily wired until I have more time tomorrow. I plugged in my ecu, which has been reprogramed by Wait4me Performance and primed the fuel system to check for leaks. Finding none I tried cranking it, to my disappointment it didn't fire. I confirmed spark and fuel pressure and I'm pretty sure that the injectors are firing so I'm not sure what the problem is. The guy I bought the engine off of had poured tranny fluid down the cylinders Earlier I had done my best to drain it but the spark plugs are fouled so I'm thinking that a fresh set might fix the problem. It was geting too late to keep working so I called it a night. Hopefully tomorow I will get this wrapped up.
Any suggestions on what might be wrong are apprecaited.

[69Custom]

I had the same problem with mine. It ended up that my injectors were clogged. The only true way to make sure that they are not clogged is to pull one out at and hold a towel under it and have some one crank the engine. That is how I found out that mine were clogged. You just have to tap them till they work again. I know that it sounds weird, but it works.

[shifty]

Verify you have power to your injectors, and that you actually have fuel pressure (i.e. your pump is engaged) You should hear the pump kick up for 1-2 secs when you turn the key to ACC position. The left and right injectors/cylinders have separate power going to each, so be aware you need to test both banks.

Also, on the Wait4Me harness, only three wires required for hookup for power: run the purple line to your stock purple wire coming off the bulkhead (IGN), orange wire goes to constant power (BATT fused w/10A) and red is ACC power w/15A fuse.

You will need to run a relay for the fuel pump, sorry if you know this already, but the Wait4Me harness has the fuel pump signal wire - run it into the relay, then add your power from batt, ground it, and then run the power out from the relay to the fuel pump.

There isn't much to do - make sure you've got all your grounds in place, this is a common problem - stock grounds go from cab to frame, bed to frame - you hsould have a ground from BATT to inner fender, from BATT to the engine block, and some suggest running from engine block to the frame as well. Bad ground accounts for 50% of the no-start problems I see at ls1tech (seriously), the rest is related to bad wiring and/or not putting power to the injectors properly.

PS - for wiring, I know you're going budget, but go to www.currentperformance.com and look for their Stand Alone wiring kit model# SA-1000

I bought it - has every fuse I need and all of the runs, power taps, etc. I'm going to rewire the truck with it

[68fleetsidec20]

Today was very frustrating, for most of the day I was trying to figure out why it wouldn't run. I keeped confirming spark and checking the injector harness. I had spark and my homemade injector test light confirmed they where getting a nice pulse. But it still wouldn't run. I checked fuel pressure, then thought maybe the fuel rails were full of air, mad sure they weren't, but it still wouldn't run. To make things more interesting the #2 cylinder always fired but no others. I took some time off scratching my head to make the passangers side exhaust. Then I tried some more and around 8:00 came here to check to forum. 69custom had the solution it was indeed clogged injectors. I pulled them out and 10 minutes later had the engine running. It was a huge relife, but all the time I wasted prevented me from getting the truck done so I won't be driving it to work tomorrow. I still need to do the drivers side exhaust, mount the passangers side fender and hood, remove some un-needed wiring (old alternator harness) and finish a few things with the engine harness. Hopefully I can get this all done tomorrow and only fall one day short of my one week swap goal.

Thank-you 69custom for your suggestion It really helped me

Shifty; Thanks for all your suggestions, for the record I only got the computer programmed by wait4me, I did the harness myself its not to complicated if you have the pinouts which I found on ls1tech.com. And as pictured above I used a 94 grand prix fuse/relay box. It proved to be a great budget alternative to buying an aftermarket system and has provisions for 5 relays and 13 fuses.

Killer71; The air filter is a K&N RE0870

[69Custom]

You are welcome. I took me some time to find out what it was as well. I was so frustrated I could not put it into words until someone else on the forum pointed me in the right direction. That is what this is all about. Do you have all of the pinouts still for the wiring harness? I had my done by currentprerformance and he didn't remove the un-needed wires and such. Also I had one wire get smoked and not sure which one but it still runs.

Thanks
Jeremy

[68fleetsidec20]

I pretty much got it all wrapped up today, at least enough to start driving it. A new intake is in the plans as well as hooking up the check engine light, the OBDII connector, finishing the exhaust past the mufflers and probably a few thousand other smaller details. I didn't get to the insurance place in time so I won't be able to start driving it until tomorow after work. I'll get some more pictures tomorrow.

69Custom; I have attached the document for the pinouts, if you have any other questions just let me know.

[RacnJsn95]

You mentioned the spacer, and bolts for the torque converter, but you said you had to drill your own holes... GM Actually makes a flywheel that you generally use with the spacer and the bolts, that is a direct bolt on for old coverters... You just saved yourself some $$ though by redrilling your old one. Nothing wrong with that!

I'm building a 5.3 (w/ a T56) for my 68 Chevelle right now, but I don't anticipate it to be done for at least a year or two. The old 350 is fine for now.

That's amazing that you could do all that in a little over a week... I wish I had that much time, and patience. Looks like a nice clean swap! Excellent work! I can't wait to hear how you like driving it.

[68fleetsidec20]

RacnJsn95; I was aware that there is a flexplate for this swap, however from reading another persons swap I was under the impression that the stock flexplate had bolt holes that would line up so I was planning on that. With carefull drilling I see no problems with doing it this way. AS far as time I only put about 45 hours into it over the week and oculd have done it much quicker if I could have forseen all my problems, but the patience was definatly needed

OLDIRON69; I will post a complete build cost summary when I have time to put one together.

gringoloco; What kinda video do you want to see? You have all seen engines run before, and I can't see burnouts being that cool in an ugly old truck like mine, so what do you want from me?


I know I said I would post yesterday but I took a little break from this truck thing to catch up on everything I negected for the past week. I have been driving it to work. The first time I drove it was to work which is about 35 miles away so I was a little nervous. but I had no problems and I am now pretty confident in it. It definatly has more power then the old 350 and it is very smooth, I haven't really opened it up yet as my throttle cable only allows me to get 3/4 throttle so thats an item for the to-do list.

Well here is some picture of the running install, I still have a lot more work to do to clean up the wiring, fix the throttle cable, make an intake, add some tailpipes to the exhaust, maybe paint the ecu black so it doesn't stick out so much and probably a few more things.




And now to let you see my truck, possibly the ugliest genIII swap vehicle out there, but it is a work in progress and be sporting some beter sheet metal and a lot more black paint over the next few months.


the oil spots on the drivway are actually from my firebird not the 5.3L

[68fleetsidec20]

I thought it was about time for an update. After I got the truck running I spent all my spare time for the next 2 weeks building a race car, then spent the next week at California Speedway, then the following week waiting for our loaner Ford F350 diesel to get its head gaskets replaced in LA. Since I got back from California I still haven't had much time to do much of anything with the truck but I drive it at least 70 miles everday and haven't had any problems. Its nice to have an engine that is completely reliable, fires up every time, is twice as good on gas as the tired 350 I pulled out, and has more then enough power to get me to work everyday. I did finally finish the air intake and figured out how much this whole thing cost me. The total came to $2,690.71CAN ($2,565.21US) However had I been a little more carefull to make sure the engine was more complete when I bought it and used cheaper stainless braided lines and standard AN fittings I figure it would have only cost $2,144.44CAN($2,067.96US)
Attached is a picture of my air intake and an excel spreadsheet of purchased parts