Engine Advice Needed - CA Smog

[Jwillis]

I have a 79 Chief with a 360 in it. My plan was to do a vortec swap but the more I read about CA smog the less I feel like that’s the right choice. For the most part I wanted to do the vortec for reliability and fuel economy.

At the same time I love the old school technology of a carburetor and it feels cool to keep that with the Jeep. I’m comfortable spending the money to do the swap so I’m wondering if there are better options.

Is there a way to update my 360 to improve the mpg and performance (I’m hoping to get around 14mpg)?

Can I swap in a different engine that has a carb that is a better engine?

I’m thinking a new transmission and transfer case is in my future as well.

Any help is appreciated!


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[Stuka]

Howell has a CA smog legal EFI kit. This would result in better reliability and slightly better economy.

Doing an engine swap can be done in a smog legal way. Basically the engine has to be newer than the model year of your Jeep, and you have to retain any emissions equipment that came with that engine. Which is basically a cat, evap system, and the air cleaner setup. Then you go to a referee and have them verify everything.

There is also a few people that have purchased a GM smog legal crate engine. This is obviously the most expensive as its all brand new.

[Jwillis]

Howell has a CA smog legal EFI kit. This would result in better reliability and slightly better economy.

Doing an engine swap can be done in a smog legal way. Basically the engine has to be newer than the model year of your Jeep, and you have to retain any emissions equipment that came with that engine. Which is basically a cat, evap system, and the air cleaner setup. Then you go to a referee and have them verify everything.

There is also a few people that have purchased a GM smog legal crate engine. This is obviously the most expensive as its all brand new.

Thanks! Is this the smog legal crate your mentioning? https://westcoastengines.com/53-crate-engine/


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[Stuka]

Howell has a CA smog legal EFI kit. This would result in better reliability and slightly better economy.

Doing an engine swap can be done in a smog legal way. Basically the engine has to be newer than the model year of your Jeep, and you have to retain any emissions equipment that came with that engine. Which is basically a cat, evap system, and the air cleaner setup. Then you go to a referee and have them verify everything.

There is also a few people that have purchased a GM smog legal crate engine. This is obviously the most expensive as its all brand new.

Thanks! Is this the smog legal crate your mentioning? https://westcoastengines.com/53-crate-engine/


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It is not. I was speaking of the GM E-Rod engines.

https://www.chevrolet.com/performance-p ... ansmission

I do not have any knowledge of the one you posted. But I know several people here in CA have E-Rod engines in their Jeeps and pass smog.

[Jwillis]

Howell has a CA smog legal EFI kit. This would result in better reliability and slightly better economy.

Doing an engine swap can be done in a smog legal way. Basically the engine has to be newer than the model year of your Jeep, and you have to retain any emissions equipment that came with that engine. Which is basically a cat, evap system, and the air cleaner setup. Then you go to a referee and have them verify everything.

There is also a few people that have purchased a GM smog legal crate engine. This is obviously the most expensive as its all brand new.

Thanks! Is this the smog legal crate your mentioning? https://westcoastengines.com/53-crate-engine/


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It is not. I was speaking of the GM E-Rod engines.

https://www.chevrolet.com/performance-p ... ansmission

I do not have any knowledge of the one you posted. But I know several people here in CA have E-Rod engines in their Jeeps and pass smog.

Thanks! I’m looking into them now! They might be outside my budget but I’m figuring out all my options!


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[Stuka]

Build thread here started with a tahoe engine I think, but he ultimately went with an E-Rod: https://www.fsjnetwork.com/forum/viewto ... =12&t=6577

[j10jim]

Go with the Howell EFI kit. That is what I did 2 years ago and never looked back. I will have the J10 in Ouray, next week for the 2021 FSJ run.

[Jwillis]

Go with the Howell EFI kit. That is what I did 2 years ago and never looked back. I will have the J10 in Ouray, next week for the 2021 FSJ run.

I’ve looked into that. I’m just hesitant to spend that kind of money until I’m sure I’ll stick with this engine. Glad to hear you love it!


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[tgreese]

Realize that your swap won't yield the same mileage as the donor vehicle. It'll be better, but the old chassis won't have the same aerodynamics and bearings/axles/etc of the donor. The wind is a mighty barrier.

You can increase your mileage significantly by driving a bit slower. That plus the EFI conversion may get you close to the 14mpg goal. Keep the tire size and ride height down; both will increase drag and lower mileage.

I would not consider an engine swap without swapping in the modern overdrive automatic and its transfer case, along with the engine. The TH400 is very strong, durable and shifts nice but has lots of internal friction compared to the the modern automatics. This would be a good way to solve the Quadratrac issues too. The offset rear axle for the Quadratrac may be a problem with the centered GM transfer case. You should look into this before you make a decision.

[Jwillis]

Realize that your swap won't yield the same mileage as the donor vehicle. It'll be better, but the old chassis won't have the same aerodynamics and bearings/axles/etc of the donor. The wind is a mighty barrier.

You can increase your mileage significantly by driving a bit slower. That plus the EFI conversion may get you close to the 14mpg goal. Keep the tire size and ride height down; both will increase drag and lower mileage.

I would not consider an engine swap without swapping in the modern overdrive automatic and its transfer case, along with the engine. The TH400 is very strong, durable and shifts nice but has lots of internal friction compared to the the modern automatics. This would be a good way to solve the Quadratrac issues too. The offset rear axle for the Quadratrac may be a problem with the centered GM transfer case. You should look into this before you make a decision.

Thanks! I was communicating with Novak about what I need for the swap and they mentioned all the same things!new transfer case and transmission for sure and then a new rear axle. $$$$$$


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[tgreese]

Note that the rear axles from '80 up are centered, or you could find an axle from a '74-79 WT Cherokee with a manual transmission. Likely you would need to regear to make the axles match. A J10 rear axle is another possibility, though it will be a somewhat wider rear track to accommodate the J10 bed width. I suspect there are other axles from other marques that might work.

Some have done this swap without replacing the rear axle. Reports vary.

[Jwillis]

Note that the rear axles from '80 up are centered, or you could find an axle from a '74-79 WT Cherokee with a manual transmission. Likely you would need to regear to make the axles match. A J10 rear axle is another possibility, though it will be a somewhat wider rear track to accommodate the J10 bed width. I suspect there are other axles from other marques that might work.

Some have done this swap without replacing the rear axle. Reports vary.

Thank you for that info!


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[Stuka]

Note that the rear axles from '80 up are centered, or you could find an axle from a '74-79 WT Cherokee with a manual transmission. Likely you would need to regear to make the axles match. A J10 rear axle is another possibility, though it will be a somewhat wider rear track to accommodate the J10 bed width. I suspect there are other axles from other marques that might work.

Some have done this swap without replacing the rear axle. Reports vary.

As I recall, WT rear axles are the same between manual and automatics. Only narrow tracs had the different offset for use with the D20 or Quadra-Trac.

[tgreese]

Huh... the housings are different WHT or WMT, but the '79 model 17 axle shafts are the same for both. Must be some detail that's different with the housings. I wonder what the reasoning is, and if they split the offset for the WT.

[89_Wagon]

FWIW, I took a round trip yesterday to the white mountains of NH with my TBI + AW4 setup... Good mix of driving with steep grades, highway, ect. I got somewhere around 16 mpg with the AC blasting. That's with a 360 that has some kind of internal engine slapping sound. Keep in mind though, my suspension and tire setup is stock. I think an OD transmission could get you to 14 mpg and maybe higher on a carb setup.

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[letank]

my take: the carb works fine... simple, easy to fix - at least as long as we can get parts- The ignition box is an easy swap... in doubt you can go HEI... but keep your distributor gears

For the vapor locking... electric fuel pump, simple and easy to replace...

Redo the ground circuit with good contacts battery to engine, engine to frame and add a few, for the distributor and to the in cab accessories, just in case.

Recheck the PCV circuit, that pesky PCV valve has a plastic fitting... and yes the plastic will distort with time and create a slight vacuum leak... in fact the manual suggest replaced every 17K or less than 5 years... forgot the exact numbers...

Add a TFI coil and a large cap distributor... that is a very good upgrade, and the ammeter bypass

A swap will cost you $$$, as for the mpg gains, very unlikely to recoup any savings, because you will gain extra power and have fun with it. Unless you drive over 12Kmiles a year, little savings. Yes it will cost money... IIRC my last Ouray or Moab trips were in the $700 for round trip from California... around 13mpg average, even if some fill up claimed 14 or 15mpg, driving 60+mph... I had a trailer with 2 off road bikes. Stock height and tires... These things are shaped like a brick... not really a chance to gain significant mpg, unless driving 55mph... with AC you will use more gas, and our AC is not that good...

Also California gas is not good for mpg, we loose 1 to 2 mpg... that you gain when going out of state...

Of course when the engine will be tired... it will be another story... How many miles on the odometer?

[tgreese]

Ya know, I kinda think that $1500 for the Howell kit is not a big expense, considering how much a swap would cost. You should be able to sell the pieces for some large fraction of the purchase price, if you later wanted to go in a different direction. It will also greatly simplify the smog plumbing - look at the manuals on their product page https://howellefi.com/product/k247jpv8w ... 401-clone/

[Jwillis]

my take: the carb works fine... simple, easy to fix - at least as long as we can get parts- The ignition box is an easy swap... in doubt you can go HEI... but keep your distributor gears

For the vapor locking... electric fuel pump, simple and easy to replace...

Redo the ground circuit with good contacts battery to engine, engine to frame and add a few, for the distributor and to the in cab accessories, just in case.

Recheck the PCV circuit, that pesky PCV valve has a plastic fitting... and yes the plastic will distort with time and create a slight vacuum leak... in fact the manual suggest replaced every 17K or less than 5 years... forgot the exact numbers...

Add a TFI coil and a large cap distributor... that is a very good upgrade, and the ammeter bypass

A swap will cost you $$$, as for the mpg gains, very unlikely to recoup any savings, because you will gain extra power and have fun with it. Unless you drive over 12Kmiles a year, little savings. Yes it will cost money... IIRC my last Ouray or Moab trips were in the $700 for round trip from California... around 13mpg average, even if some fill up claimed 14 or 15mpg, driving 60+mph... I had a trailer with 2 off road bikes. Stock height and tires... These things are shaped like a brick... not really a chance to gain significant mpg, unless driving 55mph... with AC you will use more gas, and our AC is not that good...

Also California gas is not good for mpg, we loose 1 to 2 mpg... that you gain when going out of state...

Of course when the engine will be tired... it will be another story... How many miles on the odometer?

Thanks for the advice! 66k is on the odometer. I don’t know any of the history of the Jeep so I don’t know if that’s 66k or 166k.


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