Build a Hot-Running Mopar 360 for Street and Strip


Affordable Small Block Mopar Power

The Mopar 360 is the easiest and cheapest way to build a fast small-block Mopar. It makes more power than the 318 and it's a lot cheaper to build than a 340. It's also the easiest to find. After-market support for the 360 is great, and with the right parts it can easily make 450 horsepower and still have great street manners. If you need more inches, it's easy to drop in a stroker crank and get 406 cubic inches.

Why Build a Mopar 360?

If you want an affordable high performance small-block Mopar, the 360 small block is your best choice. Parts and information are easy to find, and since it's a fairly popular engine, they are not too expensive.

Why is the 360 the best choice for a high performance small-block Mopar? Size and availability. The 318 is a great engine, but it gives up too many cubic inches in a purely performance application. The 340 makes an awesome performance engine, but it's rare, hard-to-find, and expensive. That leaves the 360.

The 340 does have a better performance reputation, but the 360 is actually a pretty good choice too. It offers 10 more cubic inches than the popular 350 Chevy, along with shaft-mounted rocker arms and a better rod ratio. Parts availability is almost as good as the small-block Chevy, if a little more expensive. It's pretty easy to get 400 HP from a Mopar 360 using mostly stock type parts. With the right modifications, you can get up to 500 HP on pump gas without nitrous or other power adders.

If you've never rebuilt one, How to Rebuild the Small-Block Mopar from SA Design has all the info you'll need. This book covers both the earlier LA series and later Magnum small blocks so it doesn't matter what style 360 you have. If you are only interested in the LA series engines, I actually prefer How to Rebuild Small-Block Mopar Engines from HP Books, but it's sometimes hard to find a copy at a reasonable price.

The Most Cost Effective Modification

There's an old racing proverb that says, "there's no replacement for displacement." The easiest way to go faster is to build a bigger engine. In the past, this could be very expensive. However with the proliferation of low-cost, semi-custom parts, this is no longer always true. For example if the crankshaft in your 360 needs to be reground, it's almost just as cheap to by a new (cast) one from Eagle or Scat. Or maybe your stock crank is OK, but you want to upgrade to a forged crank. You can do so for only around $700.

In both cases, the stock stroke (3.58") crankshaft costs almost exactly the same as a stroked (4") crank that will turn your 360 into a 408 (assuming a 0.030 overbore). Besides the extra 48 cubic inches, the longer stroke pushes the pin further up on the piston. This gives you a couple of advantages. First, it reduces piston rock. This makes your engine quieter at start-up and helps reduce friction, making your engine last longer and helping it produce more power. Second, it shaves about 1/4" of solid aluminum of the top of the piston, making it lighter. For example, if you're using Keith Black pistons, the 408 package (piston and pin) is at least 23 grams lighter (almost 1 oz.) than the equivalent 360 package. This is dependent on application, in some instances the difference is substantially more.

About the only extra work you need to do to gain these advantages is a little block clearancing on the bottom end. That's it. Any competent machine shop should be able to do this for you. If you want more information about building big inch small block Mopars, you should check out How to Build Big-Inch Mopar Small Blocks. This book tells you everything you need to know.

360 vs. 340

In stock form, the 340 is a better performance engine. If built to the same specs though, the 360 will make at least as much power as the 340 at a lower RPM. The 360 is also easier (and a lot cheaper) to find. For racing, the 340 has more potential, but for street use the 360 is a better choice.

Hotrodding the 360

Like most American V8 engines, the Mopar 360 can make decent power using mostly stock parts. If you're serious about making lots of power with decent reliability though, there are some areas that should be tended to.

Scat lightweight crankshaft
Scat lightweight crankshaft | Source

Forged Crankshaft

The stock Chrysler 360 crankshaft is cast iron and externally balanced. It's OK for moderate performance or light racing use, but if you're planning on making serious power it's better to go with an aftermarket forged crank. Both Eagle and Scat make reasonably priced forged crankshafts for the 360 (the Scat cranks are slightly more expensive but a better reputation for quality). Besides being stronger than the factory crankshaft, the aftermarket pieces are internally balanced so make sure to get the correct harmonic balancer and torque converter (or flywheel) to go with it.

Scat connecting rods small block Mopar
Scat connecting rods small block Mopar

Connecting Rods

The stock 360 connecting rods are OK for street use if have them Magnafluxed and checked for straightness, replace the rod bolts, and have them resized. By the time you do all that it's almost as cheap to go with a set of aftermarket connecting rods. The aftermarket rods are made out of better steel and they're also brand new. You know they haven't been abused by a previous owner. For me it's an easy choice. Up to around 450 horsepower the I beam rods are better (cheaper and lighter). If you're making more than 450 horsepower get the H beam rods (and send me your build recipe).

Pistons and Rings

The Mopar 360 never came from the factory in a high compression version. Factory pistons were cast and could have as much as -0.100 deck height, making for low compression and crappy efficiency. For a performance build, you should go with after market pistons with close to zero deck height. Use hypereutectic or forged, depending on intended power level. Using a piston design that uses 1/16" rings instead of the stock 5/64" reduces friction and gives you some free horse power. For pump gas, don't run over 9.5 compression with iron heads or 10.5 with aluminum heads unless you really know what you're doing.

Lunati VooDoo cams
Lunati VooDoo cams


There are almost as many opinions on camshaft selection as there are engine builders. When building a small block Mopar, the main thing to keep in mind is that most cam companies' "stocking" cam designs are likely optimized for the small block Chevy, and are unlikely to be the best choice for you Mopar. Make sure to work with an engine builder or cam grinder who is knowledgeable about what works best with the small block Chryslers. No matter what cam you run, you should upgrade to adjustable rocker arms. The stock, stamped rocker arms aren't adjustable and they cost you valve lift because they only have about 1.42 lift ratio instead of 1.5 as advertised. After market adjustable rocker arms have a true 1.5 ratio (they are also available in higher ratios) and offer adjustability. This is important even with a hydraulic can so that you can properly adjust lifter preload.

Intake Manifold and Carburetor

The Edelbock Performer RPM Air Gap is the best intake manifold for the Mopar 360. It's a lot taller than the stock intake, though, so be sure to check hood clearance. It works great with a Holley 750 vacuum secondary carburetor (3310 with secondary metering block installed). The stock 360 4-bbl intake is actually a pretty good piece too so if you're on a tight budget don't feel bad about running it. The only downsides is the weight - cast iron is a lot heavier than aluminum. Also, tuning parts for the factory Thermoquad can be hard to find. Of course, the ultimate setup would be a factory Six Pack - they're available brand new as a complete package for around $2000. In spite of being over 40 years old, the Six Pack runs almost as strong as the performer RPM and looks a lot better.

The 360's stock intake manifold and Thermoquad carburetor is actually a pretty good setup and can save you a lot of money over an aftermarket intake and carb. Back in the 1980s, Bob Lambeck was running 12 seconds in a 360 Duster equipped with the stock intake.The only downsides are the extra weight of the stock cast iron intake manifold and the difficulty of finding a decent Thermoquad carburetor. Personally I don't think the weight of the intake is a big deal on a streetcar, and you can find good re-manufactured TQ's for as little as $120 with a simple Google search, which is an outstanding deal - in fact I got one for the 360 build I have planned this summer.

The Final Word

The Mopar 360 can make an excellent performance engine. It was introduced with a 2-bbl carburetor in 1971. Not intended as a performance engine, it also featured a cast crankshaft and low compression ratio (8.5 to 1) cast pistons. When the 340 was discontinued in 1973, the 4 barrel induction was transferred to the 360 but the cast crank and low compression ratio remained. Quality control was also not exemplary during this time frame. That, combined with overly large main journals caused the 360 to gain a reputation for spinning bearings. In spite of this rocky start, the 360 can be built into an excellent street engine. All you need is attention to detail and proper selection of parts.

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Please sign my guestbook. 19 comments

chris 7 days ago

1974 Plymouth fury iii with 360 great post

Jim 3 weeks ago

Definitely very useful information, I am building a 2010 dodge charger with the early 80,s 360. Of course there's a crap load of mods but when it's done it will be a one of a kind. If anyone out there has made this swap email me with your recipe, any help to save time and money will be appreciated. @ . Thanks for the posts!!

matt 6 weeks ago

Definitely useful and well sourced info. I'm building a .030 over 360 for my 87 Dakota. Thanks to what I've learned from this article. I'll be going with the 408 stroker set up. Just bouncing between a proform aluminum carb and a six pack set up. I plan on making it a beast.

chuckjones 3 months ago

thanks for all the information about rebuilding the 360 because I'm going to be one and it will be my first timeI'll take pictures of it and keep all the information to let you know how the performance and my setup is thanks a lot

big ed 11 months ago

on the strong 360 for the street mention above what are your head recomendations 24 months ago

360LA, Hands down the best steet/strip motor on the planet, .528 mopar solid lift cam, J-heads ported and polished, 9.5 street friendly compression, I beam rods, M1 single plan intake with a 750DP. Trans. 727 with a 4200 stall converter, 4.30 gear, M&H Dot wrinkle wall 28" tires, you better hang on, cause you just built a 12.5 second ride in a 3500lb car.. Have fun!!

Vegas10 2 years ago


Have a 1990 Ramcharger that is well on it's to being a real head turner but as we all know looks aren't everything. Currently has a stock 360-2 barrel which doesn't come close to giving me the power I not only want but need. I love my Mopar but this is a real dog that needs major league help. Could use your suggestions..stay with the 360 and rebuild, go big block, go with a new crate engine...I know, the possibilities seem endless. Thanks,

CampingmanNW profile image

CampingmanNW 2 years ago

413 was the Mopar for me. I put that engine in a 1953 Ford F-150. There were only two things that Truck would not do when I finished. One, accelerate straight down the road and pass a gas station. Thanks for a fun look back.

kyle-d-redman 2 years ago

please emai me at im about to rebuild a 360 and put it in my 85 dodge power ram truck in place of the 318 that's in it.........i was wondering if a holley 650 would work on the thermoquad manifold?

anonymous 3 years ago

@anonymous: We are building a 1918 Dodge Brothers roadster with a 360,can't find streetrod headers.

anonymous 4 years ago

need that to put in my 38 y old citroen 2cv

anonymous 4 years ago

Hi Roy nice post, I am 3rd generation mopar, My dad and I built a 1915 Dodge brothers roadster candy apple purple w/ 360 it moves like nobody's business, we have always used TQ's if we could get them, I have 3 in good condition stockpiled back. my oldest son is building his first 360. well enough rambling just wanted to say nice read hear.

glenbrook profile image

glenbrook 4 years ago Author

@anonymous: Hi Roy,

I got my Thermoquad from an outfit in Texas called AAAA Automotive. My guest book won't accept html but I put a link above under Stock Intake Manifold. You can also call them at (903)546-0024. They're open M-F, 8-5 central time. They're friendly and ship fast.



anonymous 4 years ago

would like to know where you got the thermoquad carb ?great info

Tradeshowhobo profile image

Tradeshowhobo 4 years ago

Great lens. thanks.

tdove 7 years ago

Thanks for joining G Rated Lense Factory!

Charlino99 profile image

Charlino99 7 years ago from USA

I remember the Mopar. Nice lens.

Suzie-Shine profile image

Suzie-Shine 7 years ago

It's all way beyond me! But sure it's of value to others.


norma-holt profile image

norma-holt 7 years ago

Well constructed lens with heaps of info for the enthusiast. Well done

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