Build or buy 408?

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R

Ryan.

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Battle Ground, WA
I've decided on going with a 408 for my 71 Duster but I still have some questions.. Would it be more cost effective to buy a 360 and build one? Or would it cost about the same so I should just save myself the headache and buy a 408 crate engine? I've been looking at some of the crate engines and they run anywhere from 5K-7K depending on what you're going for.. I'm also trying to decide if I should go with EFI or not..

The goal I'm trying to achieve is something that I'm able to drive to work every now and then but also go to the strip and give the big block guys a run for their money. What are your thoughts?
 
Do yourself a favor and skip the crate engines from big companies and contact Brian at IMM in Indio, CA, or Mike at MRL in Michigan.
They're both regulars here and will do better by you than some engine out of a catalog.
 
There are a ton of variables to consider. On the one hand you need:

1)a place to do the work that you can keep tied up with the project for awhile

2)a competent machine shop that you can trust. I'd suggest you choose one that has more experience with high performance Mopar engine builds. They'll be more likely to know whatever tricks there are to help you out.

3)tools. You need to assess what tools you will need to get the job done.

4)knowledge. Talk to Mopar engine builders. Read. Check out some of the build threads on sites like FABO for suggestions on component choices. A poor cam/intake/exhaust/carb combination might yield you more power than the engine produced in stock form but not as much as one with matched components. Understanding things such as how to degree the cam and measuring ring gaps will be important if you're doing the assembly.

Either route you choose you should make a plan first. Know how you will set up the rest of the car (which transmission, gears, converter, etc...). Estimate how much street time the car will see. It's not as much fun using a 6mpg car as a daily driver as a 15mpg car. Many will say gas mileage doesn't matter but the thirstier it is, the less you'll probably drive it. On the other hand, you may end up disappointed if the power level is of more importance to you than the miles per gallon and you build for economy. So you do need to set some goals.

Having an experienced engine builder do the work for you offers you some advantages:

1)Your garage won't be tied up so long.

2)less mess to have to contend with.

3)You can focus on other aspects of the car build while the engine shop is building the motor.

4)An experienced shop is less likely to screw something up. If you're careful it shouldn't be too likely that you will either.

5)Many engine builders dyno their work. It gives them a chance to make sure everything is working as it's supposed to and provides you with solid reference numbers to use. - Knowing a motor's torque curve can help you set up the car.
 
71beater said:
Do yourself a favor and skip the crate engines from big companies and contact Brian at IMM in Indio, CA, or Mike at MRL in Michigan.
They're both regulars here and will do better by you than some engine out of a catalog.
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- Totally agree. Crate motors can be a crap shoot. Guys like Mike at MRL will work with you to get you what you want/need. Either build yourself or have a GOOD shop do the work for you. I'd skip the off the shelf crate motor idea.
 
Built my own 408( KB hyper pistons/reworked stock rods/Edelbrock RPM's home ported/flat tappet solid cam) After all the machine work & assembly, had over 7k in it. I like the idea of IMM/MRL/or even RAMM ( a member here) ,to do one up for you.
 
The only way you will ever know ABSOLUTELY, POSITIVELY: what your clearances are...if your cam is in right.......compression?...how's the deck surface??? is if you do it yourself.

My way of thinkin' is only the cook knows forsure what's in the soup, and sometimes even the best chefs in the world might forget the oregano.

If you have the time and tools you can do it. Get a good "recipe" from this forum, find a GOOD machinist and away you go.

Then again, you can buy one from one of the reputable guys mentioned above.
My 2 cents worth.
 
Tools aren't an issue, but I can always use more knowledge. I think I'd really like to build my own, I'll just have to do more reading on ideas for the 408. I already have A518 transmission, and an 8 3/4" rear end with 391 gears.. From what I have read it sounds like those would work well with that engine.

Might it be better to buy all the parts individually or purchase a stroker kit? Does anyone have a kit they recommend?
 
Ryan. said:
Tools aren't an issue, but I can always use more knowledge. I think I'd really like to build my own, I'll just have to do more reading on ideas for the 408. I already have A518 transmission, and an 8 3/4" rear end with 391 gears.. From what I have read it sounds like those would work well with that engine.

Might it be better to buy all the parts individually or purchase a stroker kit? Does anyone have a kit they recommend?
Click to expand...

It's an adventure,for sure .. The Scat rotating assembly is nice,get the forged piston option, if possible .. I would have it checked for balance, these kits are close, just not dead on.. ( look for one or two grams difference, if possible).. Cylinder head wise: anything flowing 255-260 @ .500" -550"@ 28" is good to go, Edelbrock's reworked, MRL'S CNC stuff, IQ52/ RAMM/IMM(Brian ,Indio CA) are all excellent choices.. To port them yourself: an option,don't recommend it, whoever ports the heads,should get cam choice.( unless you know difference) I learned a lot,( stressed a lot,too..)
 
I like buildin my own stuff.
 
I'll Sell you my 410 Stroker. I have Videos of it running. Photos and only 735 miles on it. Pm me for more details
 
turning your own wrenches will save you $$, teach you some things and give you that warm fuzzy "I did this" feeling.. until my current car, I always did and honestly, I dig the car but it just doesn't have that same sense of satisfaction.. YET. :twisted:
 
I build all my stuff and do customer work here and there, rust repairs & paint to complete drivelines. Only thing I can't do, based on really trying too many times before the idea sank in, is glass. I pay a glass guy.
So I can relate to the insecurity and need to pay a professional. Especially when the spend is great, that peace of mind carries a lot of value, in addition to normally getting more for each dollar spent.
If youwant to build an engine, go for it. If you have lofty performance goals, lack the tools and shop space, or are on a limited realistic but tight budget - you might want to pay a professional. You're in WA - as for board members here there are a couple I'd be comfortable with: IQ52 (Jim Leroy) in ID and OU812 (Brian @ Indio Motor Machine) in CA. There may be others closer to you. Ask around your local enthusiasts. They don't have to be a "Mopar shop" although in terms of having Mopar honing plates it might make a difference. They definately need to have talented machinists and modern equipment.
 
Ryan. said:
Would it be more cost effective to buy a 360 and build one?

would it cost about the same so I should just save myself the headache and buy a 408 crate engine?

I've been looking at some of the crate engines and they run anywhere from 5K-7K depending on what you're going for..

I'm also trying to decide if I should go with EFI or not..

The goal I'm trying to achieve is something that I'm able to drive to work every now and then but also go to the strip and give the big block guys a run for their money.
Click to expand...


1. Same cost or more if you have one built vs. a crate engine. Most likely more. Building it yourself? How lucky do you feel? What are your engine building skills?

2. 5-7,000 will go really quick. start just adding up part costs.

3. Do you have someone around you that has a chassis dyno and is a whizz with aftermarket EFI? If not, stay away. A good running carb will do everything you need it to and it's easy to work on.

4. A 408 is a big block for all intensive purposes. It's just physically smaller. You should be able to run with the big block guys no problem. My experience has been over and over that larger cubic inch engines are much friendlier and forgiving on the street.
 
If you want fuel injection with an overdrive in a well handling and stopping ride that looks good and performs well, you may want to consider this. Getting all of the above taken care of first and then later building and dropping in a 408" stroker motor that gets good mileage, will perform very well and is reliable might be a wiser way to go. You can likely do the motor swap in a weekend and sell the 5.9 to help recover some of your costs.

Instead of spending the $ on a stroker motor first, and then trying to upgrade the car to take advantage of it after, try it the other way around. Find yourself a nice used, low mileage 5.9 Magnum. reseal it, maybe throw in a reground cam, fresh springs, a nice double roller timing chain and do a manifold mod on the beer keg intake. Get the car running and set-up with EFI, disc brakes, suspension and sub-frame connectors at a minimum and work the bugs out of it.

Once you have it running, handling and stopping the way you want it to, then build yourself a nice stroker motor or buy a short block and heads from MRL, Hughes or someone else.

This will give you a well-functioning platform to put you motor into and allow you time to absorb lots of information about building a car to suit your intended use. It also gives you more time to save more money for your build. A lot of guys I work with have some fantasy about using this part or that, but most of it usually never matches what they are going to use the car for. In other words, have a plan to reach your desired outcome and stick with it.
 
This /\ /\ /\ is a good idea.

You won't regret spending for an OD whether it be a factory of a GVOD. I have the GVOD and I'd never have another car without one. The first time you are on the interstate with 4.56 gears behind you and you are under 3,000 RPM you'll understand.
 
I build all my stuff and have a machine shop that I trust. As mentioned when you build your own you know exactly what's in it and you can build it exactly like you want. IMO before you order the first part you need sit down and decide what your expectations are, then talk to people who have built and ran these engines to see what you need. I don't put much stock in computer programs predictions, I'd rather talk to peoples who have been there and done that.

I recommend Dave Hughes a lot, he's always been helpful and has years of experience building Chrysler engines. Plus, his cams have ran hard in everything I've put them in.
 
roccodart440 said:
This /\ /\ /\ is a good idea.

You won't regret spending for an OD whether it be a factory of a GVOD. I have the GVOD and I'd never have another car without one. The first time you are on the interstate with 4.56 gears behind you and you are under 3,000 RPM you'll understand.
Click to expand...

The A518 transmission has OD so I should be good to go on that. The way the car sits now, it has the 318 from the factory which runs fine but long term that's not what I want. I have what I need to put disk brakes in the front and I'm about to buy some suspension parts then install the 8 3/4" rear end and transmission. I think I would probably drive it around like that until I am ready to put the 408 in.

Are there any major advantages to going with EFI? Or would I be better off keeping it simple and going with a carb?
 
EFI can, read that can, make for easier startups and warmups. It allows for more infinite tuning with the possibility of less maintenance. Essentially it allows turn key, mindless operation.

My advice, and I've played with both is to go with a carb because when the EFI has an issue you are dead in the water and at someone else's mercy and ability.
 
"save myself the headache" How much time do you have. Time is money too. Is your time worth the potential headache, or do you get excited for the challenge to build it yourself?

I have way too many priorities to fret over building an engine, so I let someone who knows exactly what they are doing, perform that task. I'll enjoy it just as much, and I've pretty much touched every other part of the car, so plenty of satisfaction with my overall result.

Do some research on costs, then decide what your budget would allow, if you have someone do all or part of it.
 
FredS said:
"save myself the headache" How much time do you have. Time is money too. Is your time worth the potential headache, or do you get excited for the challenge to build it yourself?

I have way too many priorities to fret over building an engine, so I let someone who knows exactly what they are doing, perform that task. I'll enjoy it just as much, and I've pretty much touched every other part of the car, so plenty of satisfaction with my overall result.

Do some research on costs, then decide what your budget would allow, if you have someone do all or part of it.
Click to expand...

This /\/\/\
 
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