Thread: GM Gen III Engine Swap

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I'm planning to start a fat fender hot rod project in the next few months and after a week or so of Internet "surfing" I found this forum…..and I'm impressed! I've spent the better part of a day reading posts going back to September and what stands out is the depth of experience and knowledge you folks have. If I read it right you're engineers, professional car builders and accomplished "home" builders and your opinions and input are just what I need.

My project car is a '47 Ford Tudor Sedan and my plan is to build a nicely appointed daily driver with modern suspension and drive train. I want a reliable and comfortable cruiser. I have no plans, or even remote desires, for a show car nor do I want tire smoking acceleration. Although this will be my first hot rod, I have built and raced cars for over 40 years and I have both the tools and experience to tackle all aspects of the project with the exception of the upholstery and final paint.

My first questions regard the power train options. When I first started to contemplate this project I assumed that I would use an early 283-302-327-350 Chevrolet for power mostly because I already have some engines and a lot of parts. At one point I even considered a GM 4.3L V-6 but last week I ran across a deal for a 5.3 Gen III LM7 with the 4L60E complete with the computer from a 2004 Chevy pick-up with less than 4000 miles on it. I can buy this package for $1000 and I know the people involved so I know the history and I know it's not hot. Before this deal came up I hadn't even considered getting involved with fuel injection or computers but some research has shown that Hot Rodders are starting to use this series of engines. It appears that most all of the parts needed to do this swap (like wiring harness', high-pressure fuel delivery systems, etc.) are becoming available.

I'm interested in hearing about other people's experiences with this swap. For instance, is there a preferred vendor for the wiring and the re-programming of the computer? I think the truck oil pan may be too deep for a lowered '47 and I've heard that a Camaro or Corvette pan can swap. Does anyone know about this? The 2004 engine has a "drive by wire" throttle; has anyone worked with this? Are there other areas of concern? I've spoken to one vendor and read a number of articles on the Internet, but I'd like to hear from people who've actually tackled this themselves.

Should I even be thinking about this or should I just put together an old-style small block with a TH350 or a 700R4? Any thoughts and observations would be much appreciated.

Thanks for your time

Mike

Mike,

Welcome to the Forum! I say go for the Gen III swap! I am currently swapping an LS1 into my 1953 Studebaker, replacing the 350 SBC that was in there. You can track my progress here:

http://www.hotrodders.com/forum/jour...ge=1&reverse=1

To answer some of your questions, I had my harness made and computer reprogrammed by www.Speartech.com. John is extremely knowledgeable, a former GM Engineer that worked on the Gen III project. He is very helpful and willing to answer my rookie questions. I chose to have him build a custom harness, but he will also modify stock harnesses at a lower rate. I can't say enough about his service. I am using the drive by wire on my swap. I happen to have an '01 truck with it and it works well there, so I decided why not. Make sure you get all the components from the donor truck. You will need the throttle body of course, the gas pedal, and the Throttle Actuator Control (TAC) along with the wiring harness from the pedal. John is using the ETC on his camaro race car so that should provide some confidence. The pans will interchange, you will need to change the oil pick up tube as well. There is another web page you will get a tremendous amount of info from: www.ls1tech.com there is a Conversions and Hybrids forum there with info on just about every swap imaginable. I am not trying to steer you away from this forum, just showing you other resources. You will find info on other vendors that provide swap components there as well. I hang out at both places and get value and contribute to both. Hope you will do the same. Feel free to ask questions, or send me a note if I can help

Pat

I'm in the process of building up a Gen III (6.0L) with a stroker crank and a Magnuson supercharger. The Gen III series of engines are extremely well engineered. There are a couple books that breakdown what parts are better than others.

Earlier 5.3L engines used throttle cables and there should be no problems in retrofitting this system. As long as the connectors are already matched to the connectors on the engine, I don't think it will matter whose wiring harness you use. I'd just make sure they are a 'name' like Painless, Ron Francis, or similar.

Oil pans vary by the car they were designed for. GTO's have a front sump, and the rest are rear (unsure about the Cadillac CTS-V). For a lowered car, I'd definitely go with the F-Body pan (I'm using this pan too). The accessory drives all interchange, and Vintage Air now sells brackets to install the Sanden compressor in the OEM location.

The ECM's can be reprogramed if necessary, but different tuners will give different results. Be sure to get suggestions from those in your area regarding tuners.

You can find more information at LS1Tech.com.

On your chassis, I think you'll find that staying will the original frame will be the best way to go. Many companies like Fatman, Total Cost Involved, etc., make front suspension kits that can be installed on the '47 frame. It's not real hard installing a newer rear axle assembly under the back, either. You can also buy a complete frame assembly from TCI as well (a real nice set up), but these are more expensive.

Originally posted by Swifster
The accessory drives all interchange, and Vintage Air now sells brackets to install the Sanden compressor in the OEM location.

Good info Swifster. Regarding the Panless harness I have heard some stories of less than knowledgable customer support from them. I'm sure the product is good quality.

If you swap accesory drives you need to use all from the same type of vehicle as they have different spacing. The Corvette is closest to the block, then the Camaro/Firebird and finally the truck sticks out the furthest. I'm not sure about the GTO or CTS-V. The 'Vette and Camaro accessory drive will not work with the Truck intake manifold, they will interefere. You can easily swap manifolds if you chose to. The car manifolds are cleaner looking, the truck unit is pretty ugly, though it works well at low and mid range RPM.

Pat

WOW! You guys are quick on the responses!! Thanks!

I'd pretty well convinced myself on the Gen III before I posted but I wanted to hear what others have to say in case I'm missing something. Pat, you mention this fellow John as a retired GM engineer…..in my Internet search on this subject I ran across a company doing this same kind of work that is owned by Bill Howell. From what I can tell this is the same guy who worked for GM Performance 20 years or so ago. I remember getting chassis blueprints from him for a stock car project we were doing at the time. I've yet to call him, but will before this is over. And I will also definitely contact John as well.

Unfortunately, I don't have the throttle pedal or the wiring harness for it so I may have to scramble to make that work or go to an earlier throttle body with a cable which I'd rather not do.

Tom, you mention my chassis/suspension options and that was going to be the subject of my next post…….BUT… since you brought it up………

First, the Mustang II front / parallel leafs rear seem to be the standard Hot Rodder's solution and I can see why. Super easy to install, almost "plug and play" and although not cheap, certainly not totally unreasonable and I'm definitely giving that option a great deal of consideration. But I am also looking at some other options and I'd like to hear your opinions.

2) 1986 Corvette……I can pick one up sans engine and trans for $800. All suspension components, brakes, wheels and tires etc are in excellent shape. I need to determine for sure if the tread width will fit the '47.

3) I've wondered about using the GM "G" body metric frames (78-88 mid-size) or at least the front and rear clips grafted onto the '47 frame or as components for a custom frame. It looks like the tread width is just about right for the '47. These are CHEAP CHEAP CHEAP and should provide a good ride quality and handling. The low rider's have developed dropped spindles and short springs for the chassis so getting the right "stance" shouldn't be that difficult. At worst, I could see perhaps having to relocate chassis pick-up points for the rear suspension if I decided to lower the rear that far (but probably won't) and mounting the front fenders and radiator shouldn't be that difficult.

I'm not intimidated by the idea of building or modifying a frame. I've built a lot of stock car frames and understand how it's done and I own the tools to do the work including a frame table. My main design criteria is ride quality, reliability, serviceability, cost, and to an extent resale. I want a car that once I'm done building I can forget about. I don't want a high maintenance vehicle. I may be really wrong here, but when I look at the Mustang/Pinto stuff I'm not so sure that it will last that well.

Your thoughts?

Mike

The stock MII arms aren't the most durable, never have had a bit of trouble with the tubular arms, I have used Heidt's on a number of cars. Both good and bad reviews on Fat Man, never have used his stuff myself so I can't say how they are first hand. I've got a pic in my gallery of a frame for a '49 Merc that I built, all Heidt's with the air ride conversion thrown in. If you don't mind and extra bar or two on the front ent, Art Morrison has a Stree Strut for sale now, neat looking set up, best part is you can use a tubular crossmember instead of the lareger MII type crossmember, which shoul allow the engine to be mounted an inch or so lower.... Have fun with your build, keep us updated.


For what it's worth, I think that '47 Ford should have Blue Oval power, but Lord knows I'm in the minority around here!!!!!!

Thanks for the input, Dave

As I said earlier, I'm really interested in a rock solid cruiser. I want to build this car only once, and then be able to drive it anywhere, anytime, with no worries about reliability. I don't want this car to be an ongoing "project" once it's done. I've had LOTS of experience with hiem joints and they are fine in special high maintenance applications (read race cars) but I'm not a fan of them in a street application. I'm really seriously considering the Metric chassis but there are still a number of questions I need to resolve.

Ahh, funny you should bring up the Ford engine because I've also considered it as well. I looked at a Mustang II in the wrecking yard the other day with the idea of grabbing the front end and then noticed it had a 302 and a 4-speed! It is still there and I might yet just go buy the whole car. One of my absolute all time favorite engines is the 260-289-302 Ford. When I was a kid I owned a 641/2 Mustang with a 271 HP. All I can say is WOW!! What a car. We put all the Shelby suspension stuff on it as well as a set on Mondelo heads and a Sig Erson cam. It Hauled A**!! AND went around turns too!! We put the front brakes on the rear and then adapted Galaxie discs to the front and then it stopped as well!

My deal with the GM Gen III is opportunity (good price) and I think it would be fun to learn a little about the new computer/FI engines. I guess I'm not as much of a "purest" as some others. I like good stuff no matter who makes it. None the less, a small block Ford in this car is an attractive idea.

Thanks again

Mike

I agree on the heim joints, I use all Polyurethene bushed rod ends on my street stuff, save the heims for the race cars.

Oh yeah, I'm by no means a "purist", I just think EVERYTHING should have Ford power!!!!