Modern Engine Swaps and their problems

As I have said before, I am a fan of the modern American V8 engines.  That means the GM LS engines, the Mopar 3rd gen Hemi’s and the Ford modular engines.  And I am a fan of engine swaps that include them.

I have actually not seen that many swaps with modern engines.  Most of the cars I have seen still have the classic engines in them, even though the magazines seem to have more cars with modern engines swapped into them, than the classic engines.

From the magazines perspective, that makes a lot of sense.  It is something new, and it is easier to find something new to write about an LS engine than it is a traditional small block Chevy.

There are some drawbacks however.  If there weren’t, everyone would be doing engine swaps with newer engines.  The main one is cost.  It is more expensive to get all the pieces you need to put a 5.3 in a classic Chevy than it is to rebuild a 350 and put it in there.

There are some times though were it can be cheaper.  Say you want a Hemi.  If you are looking at a 426 Hemi, you better have some deep pockets to be able to afford one.  A quick look on Summit Racing shows that a Mopar 426 Hemi crate motor starts at about $16,000.  You may be able to find a Hemi for less, but that is a decent estimate.  Otherwise I will get side tracked looking at crate motors I can’t afford for a car I don’t have and not get this written.

Although it does look pretty awesome:
Engine Swaps

And  third gen Hemi has some great power potential, and can use the magic Hemi badge for a lot less money.

I know there are people who say it isn’t a real Hemi.  And it is true, the chamber on the head isn’t a true hemisphere:

Engine Swaps

But those quench areas were actually a suggestion from Tom Hoover, who was a big part of the second gen Hemi design.  Plus they help with the emissions by reducing the surface area of the head.  And they reduce the chamber volume in the head, so the pistons don’t need as much of a dome to get a good compression ratio.  That means lighter pistons.  Seems like a good trade off to me.  I don’t remember what youtube video I saw it on, but someone said those that say the 5.7 isn’t a real Hemi, need to get a real life.  It is a small thing, and I think it actually makes for a better design over all.

Now I will admit that the new engines don’t look as good as the old one.  Look at this Chevy for example:

Engine Swaps

Now compare that to the LS engine:

Engine Swaps

Even without all the plastic covers, and with a carb instead of fuel injection, it looks rather industrial.  So the modern engines are designed to run well, make power, get good fuel economy, meet emissions and be durable.  I can see why they don’t really care what they look like.  And the plastic covers help keep the engines quieter so they can meet the noise regulations.

And yes, they are more complex.  The old engines just needed power to the distributor/coil, a fuel line and exhaust and they would run.  The new ones seem to need a degree in electrical engineering to get them hooked up and running.  But that is the trade off to have a fuel system that automatically compensates for changes in weather, load and RPM.

Not having extra fuel being dumped into a engine is a large part of why the engines last so much longer today.  That and they can be built to tolerances that were beyond what race engines could be built at back in the 60’s.

Another issue is emissions.  I read that in California to swap an engine into a vehicle, the donor engine must be the same year or newer than the destination engine.  Plus you can’t put a truck engine into a car.  That doesn’t seem like a big deal, but a lot of the modern V8’s that are out there now are in trucks.

I can see the reasoning.  Trucks don’t meet the same emissions standards as cars do.  But I highly doubt that a 2000 Chevy pickup with an LS engine is going to pollute more than a 60’s Chevy.

Plus you have to keep the whole emissions system of the newer engine intact.  That means the catalytic converters, evaporative emissions and all that.  That makes it a lot more complicated since classic cars didn’t come with any of that.

I don’t know how many states follow the same rules regarding swaps as California, but I do know that all those rules add a lot to the cost of a swap.

That is too bad, because a modern motor in a classic car has a lot to offer.  I know the 5.7 Hemi when measured on a dyno like you would measure one you built puts out about 400 HP stock.  That is because of the differences in the accessories on the engine, and they way they are measured.  But that plus a cam swap, and you are 450+ HP with an easy to live with engine.  The LS engines are similar.

The Ford modular motors are not quite so HP friendly, but forced induction can fix that:

Engine Swaps

Ford even made them that way.

Another drawback to the Hemi and the Ford motors, is size.  With the Hemi heads on the Mopar, and the OHC heads on the Fords, they are wider than the standard small blocks.  They are lighter, but due to the heads, they end up being wider.

Plus, a lot of people like to stick with what they know.  The computerized fuel injection in modern car engines is complicated, and you either need to find someone to tune it for you, or learn how to do it yourself.  And it is possible to damage your engine if you do it wrong.  That is a big thought for people.

Even with the draw backs, I would love to have a Duster with a 6.1 Hemi in it.  Or a Charger.  Either way, a modern Hemi would make for a very fun car.

And the 1966 Impala in our garage would make a great place to swap a 5.3 LS engine.  Although it wouldn’t gain much for power, it would for driveability.  Too bad it isn’t in the budget right now.  Maybe some day.

How about you, what do you thing about modern engine swaps?


Modern Engine Swaps and their problems — 35 Comments

  1. Hi Pat, firstly I never seen engines so clean! then again irish roads and weather don’t help that. but again in ireland, we lack proper muscle in most of our cars, best hope here is an AMG merc or similar sports package on higher end, jags too.

    • The roads and the weather here in Minnesota don’t help engines to look nice either. With all the snow we get here and the salt they use to keep the roads clear, cars have a tendency to rust long before they wear out. It makes it hard to find good classic cars of any type around here. Most of them come from other states.

      At least there are some fun cars there.

  2. I have been to lots of car show, 10 this past year alone and have only seen 2 old cars with a modern engine swap. One was a Bel Air and the LS1 in it was pretty dirty looking.

    One issuse with emissions and modern engines is that when you install a 2010 engine into a old car. The old car must now meet 2010 emission standards and keeping the newer engine’s emissions intact. This can be a problem since modern cars use pressuized gas tanks and a gas tank pressure sensor to detect Evap system leaks. For a modern engine swap to be legal you can’t delete the gas tank pressure sensor since it is part of the OBD2 emission system. Old cars gas tanks can’t be pressurzied and modern gas tanks usually do not fit under old cars, and nobody seems to make retrofit OBD2 pressuized gas tanks for old cars.

    There is a story of a guy in CA who did a near complete LS1 swap into a 70s F body. Only thing he didn’t swap over were the gas tank and tank pressure sensor, and the CA inspectors failed him over that. He was forced to ditch the LS1 setup and go with a expensive E-rod kit which they gave the ok.

    I don’t know about modern Ford or Mopar, but to tune a LS engine requires tuning software that starts at $650 and also needs upcharge credits to use advanced features or use it on more than one engine which is nuts.

    • Yes, the emissions is a big deal, but here in MN, we don’t have to deal with emissions tests. And I still don’t see many swaps. And I think the emissions stuff is silly, since even if you pulled all the external emissions stuff off a modern engine, it owuld still be a lot cleaner emissions than an original engine from the 50’s or 60’s.

  3. Pat
    You mention that the Ford mod motors aren’t very accepting of HP unless you use forced induction.That is not true at all.You can actually take any mid 90s on up 4.6 or 5.4 SOHC and grind out the stock heads to make up to 70% better air flow and this is from stock heads..They have really done amazing things with the mod motors in the last 12 years now that we are learning about them..There are tons of aftermarket parts out there from Ford Motorsport and Edelbrock and several others. We are building a coyote right now to go in a 50 Merc custom.

    • Glad to hear I was wrong on that. It is good that there are performance parts available for them, since there are so many of them out there. Of course Ford carrying on the tradition of making parts that almost interchange with the Windsor/Romeo modular motors didn’t help, but that doesn’t seem to be anything new for Ford fans.

  4. Great article. I see very few engine swaps, and don’t know why. I’ve swapped late ’80’s era GM 3.8L V6’s into a couple vehicles, and they both work exceptionally well…and who says they need ‘tuning’? One swap was a 3.8 mated to a 700R4 into a 48 Chevy sedan, that car delivered 30 mpg with excellent power and was utterly reliable. Then I used one in a ’57 Dodge truck, and worked just as well. After studying a wiring diagram, I discovered only seven wires needed to be run from computer to key on or Batt power…and I’m not even a trained mechanic. Neither engine required any tuning of any kind, both mills had over 250,000 Km’s at time of swap!
    Next up will be a ’96 Vortec 350/ turbo 400 into a ’63 C-10. Then I’m putting Chrysler’s excellent 3.5L V6/auto trans from a late model 300 into my ’60 Plymouth.
    As far as cost, in my experience if you get the right donor, it is CHEAPER to swap than rebuild the original mill…rebuilding has gotten very expensive, I’ve averaged between 3-5 thousand to properly rebuild one, and with what result? To have a heavy old V8 that makes less power than a Modern 6, gets half the fuel mileage, negatively affect handling, is constantly on the verge of overheating, made up of parts that are getting increasingly harder and more expensive to buy, topped off with a temperamental carb that was outdated half a century ago, not designed for our modern garbage fuel, and dumps that raw fuel down the motor’s throat so it wears cylinder walls and everything else so the thing only lasts half as long?? No thanks. For less money I’ll buy a whole newer car and gut it! Anyone ever notice an injected mill feels like it has more power compared to an old carbed motor, even if the numbers on paper defy that?
    Seeing a modern injected engine with a carb adapted to it is like putting tractor tires on a Corvette.
    I say who cares about aesthetics under the hood? I prefer reliability and efficiency. “Chrome doesn’t get you home”.

    • Glad to see I am not the only one who likes modern engine swaps. For your 60 Plymouth, that sounds like a fun car. I would love to swap the 3.6 Pentastar V6 into an old Mopar.

  5. I am from minnesota. And I am looking at doing a 5.3 or 6.0 ls swap in my 84 Chevy c10 only problem I am coming up with is I want to keep both fuel tanks working and be able to switch them back and fourth . I also am trying to figure out how to make the cruise control to work with the ls swap. Any suggestions would be helpful

    • Byron,

      Great to hear from someone else from Minnesota. An LS swap into an 80’s full size sounds like a lot of fun.

      For the dual fuel tanks, the main issue is the fact that as far as I know, you pretty much need to run an in-tank fuel pump to get enough pressure for it to work. The reason is because then the pump just has to push the fuel out of the tank, and doesn’t need to try and pull it from the tank first. My first thought would be to have a fuel pump in each tank, and use relays off the switch on the dash that changes between them so that the pump in the tank that is on is active. The problem with this is that there may be a drop in the fuel pressure when you switch, since the point of the two tanks is to be able to switch on the fly, and that you have to buy two pumps.

      You can run one external pump upstream of the switch, but you would have to make sure it could handle being that far from the tank. That plus the external pumps are often noisier than the in-tank ones, since they don’t have the fuel around them to block the noise. I am not sure if they would have a shorter life span due to not having as much cooling because they are not submerged in the gas in the tank. That would be another thing to check on if you decide to go that route.

      For the cruise control, here are a couple of links to give you some ideas since I don’t have a pickup here to see how it works. They should get you started:

      • I thought of one other thing, rather than the dual tanks, you might also want to look at aftermarket fuel tanks that are larger. I have seen aftermarket fuel tanks for pickups with greater capacity so you could hold more gas, but not have to deal with making the two tanks work with the engine swap.

  6. I love the old style camaros and I love the new modern engines, suspension, transmissions. I wish GM would combine the 2. Since that’s unlikely I have to research it myself to put an LS1 into a 70’s Camaro. Thanks for your blog post.

  7. Hi There
    I have a 1965 Ford Thunderbird sedan with a 5.0 litre V8 fuel injected motor and 5 speed manual box from a 1999 AU sedan. I did most of the install myself and just needed a good auto electrician to make a wireing loom and install a computer and tune. the Tbird motor and gearbox were not working and the rebuild cost was nearly the same as the transplant. The performance is fantastic and fuel economy really good, next I want to install a blower just to see what it like.

  8. Hi, I’m from Chile and I’m doing a engine swap from a 2012 dodge ram regular cab to a 1975 chevrolet scottsdale, origilally equipped with straight 6 250 engine. (5.7 L HEMI, with auto transmission, replacing 4.1 L carburated engine with 3 speed manual trans)

    reviewing the options i found that the best choice is to purchase a crashed modern vehicle, condition run and drive, low mileage, and you will get all you need at a low cost and you only will have to fit new systems into old structure. So my new old truck will count with: New electronic dashboard; conditioning air; sound system; four wheel disc brakes and ABS brakes; Electrical assisted steering; cruise control; traction control. all this for about USD 20.000 including labour. If you considere that just an complete engine kit with ECU cost about USD 7000 is a great option, because I expect to get about USD 5000 selling ram body parts which I wont use on the project… For me the biggest issue has been administrative/law issues, because of customs regulations in Chile.. is a long story.

    • Sounds like an interesting project. I bet there aren’t to many Chevy trucks with a modern Hemi swapped into them. But given the space those old trucks have, it shouldn’t be any big issue. Just the usual electronics to figure out, and it seems like you have a good plan for that.

      I had a 1977 Chevrolet pickup, mine was the super base Custom Deluxe. It also had 250 straight six and a three speed. I still kind of miss that truck, with manual steering and brakes, there was pretty close to nothing to go wrong with it. While modern vehicles may be more reliable over all, there is something about a truck you can nearly disassemble on the side of the road with a pliers, an adjustable wrench and a good sized rock.

  9. I just found this post and was looking through it. Interesting stuff. I bought a 67 Camaro that had some of the ls1 swap done. I ripped everything out and did it right. It’s a 2002 Camaro aluminum ls1 with 4L60E transmission. Everything is a bolt on kit. Had a guy come in and reprogram the computer because it needed some fine tuning (i.e. it was looking for the cats). The car is a daily driver. I added air-conditioning to it and a Dakota digital dash. Made life way too simple. Gets 20 to 21 on highway and 16 or so in city.
    I have a 74 challenger with a 360. I have also have a long block 5.7 hemi in my garage. Maybe one day if the wife will let me. The conversion to do something like this is around $4000 for parts and that does not include the engine and trans.
    Let me know if you need anymore details on it.

  10. I am of two minds regarding engine swaps:

    an old car with a numbers matching engine, should be left as is. I was watching Fast and Loud, as they tore apart an old model T. It had a good WORKING engine. They yanked it out and put in a new (er?) engine.
    This is a travesty.

    Now if you find and old shell of a car, with no engine, no tranny, no interior, and you want to stuff it with modern stuffs, all electronics and modern conveniences, then I say “no harm/no foul.”
    If you want to make it a sleeper and keep all old stuffs while putting just modern iron in it, that would be okay too. As long as you aren’t ruining something that works and runs, I have no problem with it.

    • I am ok with pulling out numbers matching parts, as long as you keep them, and can go back to them if you want. I would rather see a car being driven with a modern drive train and the original numbers matching parts sitting safely in the garage, than seeing the car not being driven because the original stuff was too ahrd to deal with etc. Not many people any more know how to deal with carburetors, chokes, points, solid lifters etc. To say nothing of dealing with ethanol fuel with said parts.

      I love seeing and hearing the classic engines, but as long as the car is out there, it may get someone new excited about cars. And that probably won’t happen with it in the garage.

      Plus, if they are driving it with new stuff, the original engine can’t wear out and is being preserved.

  11. My wife and I just put an LS3 with a D-1 procharger in a 1970 Chevelle. It wasn’t an SS car, just a basic. We put a 4L60 tranny in it and it is a great street car. We see alot of LS swaps in our area. Pretty common on C-10 trucks also.

  12. Are there any resources out there so i can figure out electrical work a rounds? I have a 65 f100 with a 240 that finally passed away and i want to put my 4.6 from a 99 mustang in it.

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  15. I have a 1947 ford 4 door and a 1991 Lincoln town car and I want to put the 47 body on the Lincoln frame. The floor board is rusted out on the 47 so I’m thinking it will be easier to use the Lincoln floor than to replace the 47 floor and make it fit. anyone have any experience or ideas?

    • Also I have measured the wheel base on both and they have the same measurements. So the only fit I will hzve is on the floor board , do you think that will be to hard to match them , I can use as much of both to make it fit. I will use a rotisory to fit it up and doi the welding.

  16. Hello, I was going to drop a 1998 BMW 328i engine and transmission into a 1959 Studebaker Silver Hawk. I’m concerned about the electronics of the engine. Has anyone dealt with this problem.

    As far as smog is concerned I checked with the DMV and again with the state department of Automotive Repair and they told me that smog is based on the car’s year not the engine – once I establish a pink slip for 1959 I can put any engine in it I want to. This information was given to me with the knowledge that the car I was going to buy doesn’t have an existing engine.

    Do you think I’m being steered wrong?

  17. I put a 350 from a 79 Cutlass, mated to a turbo 400 tranny from an 84 Camaro into my 52 GMC half-ton truck. I also took the front clip assembly from the Cutlass as this made the engine install much easier. Of course, this meant if I took the steering column too, I could have disk brakes on the steering and of course…. power steering! It made good sense to swap the rear axle to and get rid of that horrible enclosed driveshaft and ridiculously slow gears! Hey, it’s a great ride now! Looks like a 52 but rides like a 79! I chose the 79 donor Cutlass because I could buy a “rusty but trusty” cheap ($600) and, by 79 I could avoid the points and condenser in the original. The swap also got me to a 12 volt system with an alternator rather than that problematic 6 volt generator system! Installed a new fuse panel and changed all the lights and bulbs to 12 v and I was “good to go”! Before the swap, it was a “cool ride” but it rode like an old farm truck with a box full of lumber!

    • Sounds like a great swap. The 78 to 88 GM A/G bodies are great for that, since they are pretty close to the same size, affordable and have great aftermarket support.

      I love the old trucks, and they are on the list of cars to own.

  18. This is ken from Texas I’m looking at putting a gen 3 hemi into a 64 dodge polara 2 door hard top. This will be my first modern engine swap and am wondering about issues that may arise such as wiring computers etc I have no experience with fuel injection everything I’ve ever done has been carb. I’m just wondering if anyone has any advice or things to look out for so that I can prepare for them during the planning stage I’m also wanting to put modern steering and suspension on ,any advice on parts dealers and websites were I can get information on troubleshooting issues that may arise I’d appreciate.thanks for your comments.

    • That sounds like a fun project. On the plus side, may 3rd gen Hemi swaps have been done, so it isn’t new ground. I would recommend checking out the For B Bodies Only forum at I know people have posted walk throughs of their swaps there and would be better able to answer your questions than I am.

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