LS Swap 70c10 Need help
 

Okay to start off with i am sorry if this has already been talked about here, but i am new to using forums, i created this account last year and never got around to asking but anyways to my questions and concerns.
I am in the process of trying to find a 5.3 LS for my truck and i've been doing a lot of research the past week or so and i have some concerns that i haven yet been able to clear. My first concern is on the transmission linkage. I plan on using the stock TH350(Financial reasons) that came with the 350/350 combo from the factory. now when i mate the TH350 to the 5.3 will my stock linkage still hook up and work? I will be using Dirty Dingo mounts that are adjustable for this reason, in case i have to push it forward or backward some. My Second concern is the drive shaft. Will the stock fit? Will i have to have a custom one made? Also i'm not planning to use A/C But i want to use P/S. Will the power steering pumps to these late model style trucks work with the older style gear box? Sorry if these questions can be easily answered somewhere else, if so someone please link me. i've tried my best on the web to find some info on these topics but it seems every time i find a swap on one of these types of trucks they arent very thorough on these specific topics. any help is appreciated! Thanks!

Re: LS Swap 70c10 Need help
 

1) Transmission linkage is super easy. You have two options. Use engine slider mounts and make sure the transmission stays in the same position longitudinally, or if it does not, the Lokar universal shift rod fits excellent and can be installed in about 15 minutes. I have the stock column shift and use the Lokar rod with the 4L80E.

2) If your transmission stays in the stock location, no driveshaft mods needed. Otherwise, a custom shaft would need to be build.

3) Power steering is also simple, you can simply swap the fitting from the back of your current pump to the newer pump on the LS. I even re used the stock lines after just a little bending for clearance.

Hope this helps and good luck.

Re: LS Swap 70c10 Need help
 

Appreciate the quick reply, and yes that helps a lot! wasn't even expecting a reply to be honest lol. I am still a little Foggy on the fuel delivery system, i have a buddy using a walbro 255 on his 83 c10 with a 6.0 but cant quite get a hold of him to ask him some questions. would be great to get the fuel system mapped out! Also i see your signature says your boosted, somewhere down the road i hope to do the same maybe you can shed some light on your build? or do you have a link? Would love to see it!

Re: LS Swap 70c10 Need help
 

Sure, plenty of pics here. It's a bit awkward sharing this link (I'm not self promoting) but they are nice pics.

https://theblock.com/news/nate-hines...d-lm7-1970-c10

The walbro 255 is great, especially in tank. I would not recommend that with the in cab tank though, too noisy. With these truck a rear fuel cell just works really well.

This forum has an entire LS swap section, be sure to check it out

Re: LS Swap 70c10 Need help
 

If you go with a drive by wire pedal, check out my adapter bracket:

http://67-72chevytrucks.com/vboard/s...d.php?t=651123

Re: LS Swap 70c10 Need help
 

Appreciate the help man! And Wow just kinda had my mind blown there for a sec...ive seen your truck all over my Instagram Feed before and i've wanted something similar ever since! Perfect build my friend. Love the "Patina" look. And i will im trying to get used to the forum and get a feel for things, so far its been great help!

Re: LS Swap 70c10 Need help
 

I agree that the walbro inline 255 is a little loud, but my brother in law has his mounted underneath the cab and it isn't too bad. You can hear it while driving, but the exhaust is extremely quiet.

I run 2 walbro inline 255 pumps on my turbo 6.0 in my chevelle. They work great, and haven't had any problems even though they are mounted above the pickup in the tank.

Holley also makes adapter plates that put the back of the motor in the same spot as the stock motor. No changes needed behind the motor. Heard great things about the dirty dingo mounts as well.

There are a few aftermarket dished flexplates you can use with crank spacers for the older transmissions/converters, but I use a stock flexplate/spacer from a 6.0/4L80E combo that bolts right up. Haven't had any issues with it even with transbrake launches @3900lbs.

Re: LS Swap 70c10 Need help
 

Lol, the "internet fame" was the last thing I ever expected. I just wanted a fun truck for parts hauling and sunmer daily driving. It's been great and I put over 8000 miles on it last year.

This forum is a tremendous resource, use the search function and keep browsing. I believe message boards such as this have done more for the hobby than anything before.

Re: LS Swap 70c10 Need help
 

Haha lol looks like it! And i have trust me ive been here before but never in depth enough to create an account and ask questions but its definitely worth the time.
Now time to find me a 5.3 and get started already lol pretty much got my stuff mapped out now.

Re: LS Swap 70c10 Need help
 

I know you are trying to save money by using the TH350 but your going to need a few things to use it. The engine needs a speed signal to operate properly so you are going to have to buy an electronic speed sensor to make it work. Guys will tell you, you can do away with the speed sensor but this generally results in poor fuel economy and driveability problems. I know there are also spacing differences between the torque converter and flex plate that may cause you problems?

Often you can buy an engine and trans combo for little extra than the engine alone and save all these hassles and gain overdrive. The 4L60E uses the same output shaft spline as the TH350 and with proper engine placement you can use your stock driveshaft. The total cost is likely a wash and you gain O.D.

Re: LS Swap 70c10 Need help
 

I haven't seen any fuel economy or driveability problems running the older transmissions other than the gear ratio. Been there and done that one with both stock ECU's and Holley's EFI. Either one will adjust A/F ratio depending on so many factors, that I never noticed any difference. Just my experience.

Although I have eaten up a few thrust bearings with my Hughes Th400 because of converter charge pressure+Boost.

Re: LS Swap 70c10 Need help
 

Posting Below..

Well ive been looking and i found this, was wondering if maybe i could get some feedback? i called the guy and he is an older gentleman with a history of selling these ls based engines. he said the truck was wrecked into the back of a dump truck? said it sustained some good damage to the front end but missed the engine totally(as seen in the pics on the post) and belonged to an area police dept.(Denton) and he bought it at an auction. I asked if i could crank it and hear it run, he said it wont turn over, MIL light comes on and odometer doesn't come on. i may run down and pick it up and take a shot but wanted some second opinions before i go and possibly blow a 1k bill on something that could cost me in the end.
also he mentioned he has about 4 people so far that have called and are trying to go after it but no ones showed. said he has 2 coming for it this weekend and first to give him money gets it.

https://dallas.craigslist.org/ftw/pts/5418497820.html

Re: LS Swap 70c10 Need help
 

1k seems reasonable but I would like to hear it run unless I can get some kind of warranty. But you are only going to get that from a salvage yard, if that.

Re: LS Swap 70c10 Need help
 

I have mine under the cab and I don't even know its there.

Re: LS Swap 70c10 Need help
 

Yeah my brother wanted the exhaust to be very quiet. It is actually quieter than my mom's suburban. If it had anything more than stock exhaust sound, you wouldn't ever hear the pump.

Re: LS Swap 70c10 Need help
 

Doesn't sound like a bad deal to me, but that's if it's a 2wd. If it's a 4wd, then the trans won't do you much good, assuming you're building a 2wd since you didn't mention it being a 4x4. I agree with the other poster about just getting a 4l60e to go with it, better off in the long run. You'll get a little better fuel mileage with the overdrive, and like he said, you need a VSS. Some people say you don't, but more often than not, not having one can cause stalling problems when coming to a stop.

I would look that truck over good, you can usually get an idea of how many miles are on a truck by the condition of it, or at least be able to tell if it was properly maintained. If it's clean, it could be lower mileage or was owned by someone who cared about it. If it's a ragged out pile, then it probably has a boat load of miles and if it doesn't, it's probably never had an oil change and you don't want that. A 100k plus mile LS engine is still a good foundation, since these engines are built well so don't go only on miles.

Re: LS Swap 70c10 Need help
 

Thanks man i'll definitely look it over as best as i can if i go after it. Also im guessing that the trucks check engine light is on and wont do anything because it was wrecked? could i be able and take a flashed pcm down there and somehow try and start it? theres a vid on youtube showing how to 2 wire start it but it needs a flashed pcm with vats removed.

Re: LS Swap 70c10 Need help
 

Hello, Just checking in first time, I have a 70 C10 custom long bed, trying to decide to swap out tired and abused 350 (not original) for a 350/383 or go with an LS swap. I would like to retain the AC and all other accessories. I welcome any feedback...

Re: LS Swap 70c10 Need help
 

welcome i am new here too lol and well same truck and sorta same situation for me but i put together my costs for building an old conventional engine(355/TH350 mild build) to just doing a swap and price was pretty much close to the same. So i figured well for the same price, i mind as well LS swap it, but came across a lot of concerns that have been mostly cleared on this thread. Gaining Fuel Injection, along with modern technology and performance i figured it was worth it. Also as i was told in the thread before there is a part of the forum dedicated to LS swaps also full of helpful info.

Re: LS Swap 70c10 Need help
 

I can tell you without a doubt that it is absolutely not true that you need a VSS sensor to avoid stalling coming to a stop. That is almost 100% IAC hold position and decay rate.

The overdrive is very nice and definitely worth it for the right price, but there aren't any tuning issues without a VSS. There are hundreds of people doing it with both stock ECU's and aftermarket. The stock ECU is a bit trickier, but not a problem with a competent tuner.

Re: LS Swap 70c10 Need help
 

Really appreciate the feedback buddy. Here is the posting for what i am trying to get: https://dallas.craigslist.org/ftw/pts/5418497820.html
Its altogether but if i have problems with the tranny and clearance problems then ill go with the th350 set up instead. and it makes since for it to be the IAC for stalling problems or things of that matter. the VSS on the other hand would be used to determine the speed on the input shaft of the transmission i am assuming? still learning these things at the moment lol also a fellow friend on the forum here says he can reprogram my PCM and make sure everything checks out good.(he has bascially same truck and set up im going with) so we'll see how things go. but there are still a few hiccups im trying to get figured out such as, speedo hookup, tach, odometer, and small things im sure ill run into. speaking of aftermarket ECU's what kind or brand are you talking about? i may look into that if they are tune-able because i plan on installing a cam later down the road. not anything too heavy though.

Re: LS Swap 70c10 Need help
 

No problem! The stock ecu DOES use the VSS for tuning in some spots, but very easy to work around it. I use the Holley HP EFI on my personal cars. Much easier to work with than the stock computer. Holley offers 3 ECU's that will work.

The "HP" is their basic ecu that has 4 inputs/outputs and will NOT control an Electronic transmission. ~$1500 with all the harnesses as a kit.

The "Terminator" has the same features as the "HP" but WILL control an electronic transmission. ~$2300 including the harnesses, but doesn't come as a kit together for some reason.

The "Dominator" has 20 inputs/outputs if I remember right, and WILL control an electronic transmission. ~$2600 including the harnesses, but also doesn't come as a kit.

There are a few other differences, but all 3 of those are very user-friendly while offering almost more tuning options than you will know what to do with.

Re: LS Swap 70c10 Need help
 

hey everyone i know the thread has been dry for awhile but ive come across some things i need help with. i need help with plumbing the fuel system. i have a return type rail and will be running a walbro 255 inline using russell quick connect fittings on the fuel rail. im trying to avoid using so much stainless braided fuel line(expensive) when i can use pressure rated fuel injection hose. in this case id need different rail connectors. also im assuming the pump doesnt suck from the take so it gravity fed? im using the in cab tank for a very short while until i can get my fuel cell so ill probably need to fab something for the fuel supply. and i also need a throttle cable. any help is appreciated thanks.

Re: LS Swap 70c10 Need help
 

No problems running that same pump for thousands of miles so far. Seems fine and I wouldn't worry about it for a short while at all. Pump is mounted under the cab and pulls from the stock sending unit.

I also wouldn't run very long lengths of the rubber hose. Just my opinion, but I use the braided hose or make solid line.

Re: LS Swap 70c10 Need help
 

seems like it could be a solid pump then, and all i do is run line from my stock sending unit and it will suck gas out of the tank? the reason i ask is while doing research i found a guy somewhere who said it had to be gravity fed. which now that i think about it makes sense since the pump is below the gas level all you would have to do is siphon it up and keep gas in the tank(hence the old siphon trick) and yeah i got my budget figured up now ill run braided line thought out. thanks for the help buddy!

Re: LS Swap 70c10 Need help
 

No problem! I honestly would feel better with it being gravity fed, but decided to try this out since the pump is cheapish to replace.

My chevelle has two of them mounted to where it has to pull fuel almost straight up about 8 inches. The second one comes on at 10ish pounds of boost. Haven't had any problems yet.

Re: LS Swap 70c10 Need help
 

also another quick question, on the return side of my system is it pressurized? how would i run it with the stock tank? im running rubber efi hose from my sending unit to my pump then from the pump will be stainless braided line to the feed on the rail and for the return either regular efi hose or braided if it has pressure on that side, any replies would be great thanks.

Re: LS Swap 70c10 Need help
 

The return side will have some pressure on it or else the fuel will just be sitting there. ;) The question is how much, and that's determined by how much fuel is being used at any given time, but typically it will b e a very low pressure compared to the feed line.

As for the pump sucking fuel, it can be hit or miss. There's a guy on here right now that I think is suffering from not enough fuel pressure at times, likely due to the pump trying to suck the fuel up the stock sender and then to the pump. When the pump begins to get weak, or doesn't have enough power going to it you may see a lean condition and could get a check engine light. electric fuel pumps are designed to push fuel more effectively than pulling it. I've done it both ways, used the stock sender with a pump mounted under the cab, and a gravity feed to an under cab pump. The gravity feed works much better and I have never had it starve for fuel even when the level gets low, something you will have to contend with, with a stock unbaffled tank. There are pics of both set ups in the build threads in my sig. The rusty green truck is the gravity fed one.

Re: LS Swap 70c10 Need help
 

okay i see you have a point lol and i see, well im going to try it out and see how it goes. i am needing help with my gauges if anyone can offer a little help on how they plumbed theirs(temp, oil press, ect..) ive got a fuel pressure gauge setup in the works but i am going to need others too. ive seen some here and there but want to see if anyone here has a good instructional thread or some direction for me, would be appreciated.

Re: LS Swap 70c10 Need help
 

Depends on what gauges you are using. Stock or aftermarket?

Re: LS Swap 70c10 Need help
 

Aftermarket. Using stock speedo. I'm using a Dakota digital vss adapter for the speedo

Re: LS Swap 70c10 Need help
 

Well I'm back on here again needing some help, so far everything else is good, 5.3 and turbo350 are in fuel system is good, exhaust, ect.. But now I'm trying to wire the thing up, and I'm wanting to be able to start the truck basically like original, slip the key in, turn and start it. But I'm having trouble wiring the starter up, and tracing wires from the ignition switch and things like that. I've done some research but still having problems. So far this is what I've got, I have the battery in, from positive post straight to starter, then the little lead on the starter is wired to the purple wire going to the ignition switch. And I know I may be a little air headed at the time and just overlooking something simple but I can't get it to start. I just want to be able to turn the starter over with the ignition switch and find which wires to splice into for the pcm. I'm using the stand alone conversion from lt1swap.com. does the starter have to be grounded with the other post coming off the other side or is it case grounded?

Re: LS Swap 70c10 Need help
 

Okay so after tinkering with with it for awhile I've got power to the starter when I turn the switch to crank it but all it does is just tick like I've got a lose ground or bad connection I just put brand new terminals on and tightened everything down good. Maybe the battery I'm using is too weak. I also would like yo hear how you guys integrated the old wiring harness into the standalone harness