Mopar 400 2bbl

MRL Performance · Jun 20, 2012

Here is our latest endevor, a BBM 400. Its a bit of a "Sleeper" as it is a stock looking 400 2bbl. The HP manifolds make it look a little better. Here is the run down, well as much as Im willing to tell yall anyhow.

400 BBM
4.375" bore 3.38" stroke
Stock 383 516 2bbl heads and intake
Heads were Not ported, only a blend for the new seats that we installed
Super light weight valvetrain, Beehive style springs, light weight valves
10 to 1 compression
2.08/1.60 valves
Holley 4412 500 2bbl carb
Super light weight internals, 2066g bob weight
Lunati Voodoo 60303 cam
MP iron adjustable rockers
Top end oiling mod
A few tricks here and there

Ran the water pump with the crank, not electric drive, and a real life 175* water temp. Timing was set to 34* total, A/F was 12.4-13.0.

Factory 400 4bbl rating is 190hp/305tq, and thats with a 4bbl

We ended up with 357HP @ 5200 rpm and 455TQ @ 3000rpm

It ran strong, pulled hard and sounded great. It had 16-17inches of vacuum at 800rpm, no vacuum advance. With a 4bbl intake and headers, this engine would make another 100hp easy.

Any way you look at it, its making a lot more power than a stock 400, with smaller heads, smaller intake, smaller carb. The advantages are, more compression and a mild performance cam, lighter pistons and valvetrain and few *Special* mods.

76CinnamonRT · Jun 20, 2012

I have seen so many people junk 400 motors too because they are under the impression that they don't run well...

Jack Meoff · Jun 20, 2012

Nice.
I'd like one of those.

bremereric · Jun 20, 2012

You got the longhorn stock water pump that looks like an ardvark.

slant6billy · Jun 20, 2012

I had a 72 400 given to me last year. My engine stand was rated for 1000 pounds. The 400 bent the stand. My thought was to use it in my f, but the f is front end heavy enough. I am going the route of small block, due to the weight. The power numbers look good, but what will the power look like at the wheels? depending the trans and torqueconverter, you could loose 100 to 150 hp through the drivetrain. What are you putting it in?

Erics5th · Jun 20, 2012

Why didn't you use closed chamber 915 440 heads for the bigger valves?

Roadrunner360 · Jun 20, 2012

nice build.........great hp and torque numbers........

Mroldart2u · Jun 20, 2012

So I am assuming an .060 over bore? well more like a .055 or so? and stock stroke.. I have one of these now and was contemplating on WHAT to do to/with it. IE: stroker, leave as is etc.... mine is a '72 2bbl in a 72 Newport..

efriedrich · Jun 20, 2012

slant6billy said:
I had a 72 400 given to me last year. My engine stand was rated for 1000 pounds. The 400 bent the stand. My thought was to use it in my f, but the f is front end heavy enough. I am going the route of small block, due to the weight. The power numbers look good, but what will the power look like at the wheels? depending the trans and torqueconverter, you could loose 100 to 150 hp through the drivetrain.

B motors weigh 620lbs while LA motors weigh 525lbs. 95lbs can be easily shaved off with aluminum components. As far as gross vs net HP a 12-18 percent reduction in HP was the figure I seen used a long time ago. So on this 400 motor, 357 gross hp X .85(15%loss)=303.45 net hp, not bad for a two barrel.

MRL Performance · Jun 20, 2012

.033" over 400. Yes you have to remember its a 2bbl with 383 2bbl heads AND 2bbl intake. The 915 heads are banned in the class of racing for this engine.

With these heads the way they are, flow about 243cfm@.500". With a RPM and a 750 4bbl, and headers, this engine will make 450+HP all day long!

I have another "Recipe" for a 400 that makes over 600+HP, as a 400, not a stroker.

Mroldart2u · Jun 20, 2012

MRL Performance said:
.033" over 400. Yes you have to remember its a 2bbl with 383 2bbl heads AND 2bbl intake. The 915 heads are banned in the class of racing for this engine.

With these heads the way they are, flow about 243cfm@.500". With a RPM and a 750 4bbl, and headers, this engine will make 450+HP all day long!

I have another "Recipe" for a 400 that makes over 600+HP, as a 400, not a stroker.

Well dang hope that one isn't a "secret".... :notworthy:

Erics5th · Jun 20, 2012

Ah, got ya. I had a '72 400 (that oddly enough came from a '72 Newport)in my '70 Fury III. Turns out it was a early 230 cast block. They had the extra material in the main bearing webs for extra strength. The later blocks did away with the extra beef. Just as strong performance wise as the 383 that came in the car originaly.

MRL Performance · Jun 20, 2012

Mroldart2u said:
Well dang hope that one isn't a "secret".... :notworthy:

Well it is and it isnt. If you order one, you get the build sheet. Its not something I give out freely. You understand, right?

Mroldart2u · Jun 21, 2012

MRL Performance said:
Well it is and it isnt. If you order one, you get the build sheet. Its not something I give out freely. You understand, right?

Oh i do understand..... As back in the day i was running an old junk yard 351w ford, and EVERYBODY was on the chevy bandwagon, and didnt know the difference between a 289 - 351. I had a pretty decent cam and headers, and was geared pretty low with a 4 speed... Long story short, I ate quite a few sbc's and bbc's with my "289" :jerk: It was one of those flukes ya know, ran way better than it should have, and that was when windors wasnt cool... the cleveland was the hot item then for sbf.... I wish i COULD afford for ya to build something out of my 400, but distance and money is a .... well you know... Any ways keep the builds coming, might be able to pick a pointer or two out of the avail info you do give....

Remow2112 · Jun 21, 2012

400 build

How did you get the compression up to 10:1? I run a .60 over 400 with SD intake, 452 heads, Summit 6401 cam (slightly larger then a six pack cam), headers with 2.5 exhaust and a 750 powerjection iii.

The aftermarket replacement pistons are only .80 in the hole. Which is great since most measure .120. :sad10:

I have done a best of 13.47 @ 101 in the 1/4. I am starting on my short block for the next motor (it is an addiction I tell you

) I planned on using KB240 pistions which are about .25 in the hole and was going to have the block decked to get 0 deck out of it.

Did you order custom pistons or how did you get to 10:1?

Thanks,
Dan...

MRL Performance · Jun 21, 2012

These pistons are at Zero deck. The piston rod combo is a trade secret and is super light. But its all off the shelf stuff. We are running the 516 head which is a closed chamber, that helps bump compression up. The 915 are closed chamber, that will bump up the compression too.

The piston/ring/rod combo is $1050 for this engine. But the bob weight is 2066g, way lighter than any factory BBm or SBM for that matter. Its light enough to internal balance a cast BBM crank without using any heavy metal. Plus with the reduced friction of this combo, I can spin the complete short block(without cam installed yet) with 1 finger on a 3/8 ratchet.

If you run the KB240 with the 452 heads, run the MR Gasket .020 thin head gasket as well. This will further bump the compression up.

slant6billy · Jun 21, 2012

Do the Magnum small blocks weigh less than LA small blocks? I assume they do but by how much?

MRL Performance · Jun 27, 2012

Report back from the customer after the first race with this engine:

" The engine has a ton of torque, I can spin the tires halfway down the track if I am not careful. Now I have to work on the set up of the car to handle all this power. I need to get it to dig harder coming out of the turns, all day I was driving sideways down the track and was still able to keep up with them. I finished 4th but I am sure once the car is set up so I can dig coming out of the corner, nobody will catch me."

What out you Chevy guys, MOPAR is Coming!!!!

BHA43 · Jun 27, 2012

I had a 440 crank in a 400 block, light pistons, closed chamber heads & fed it with a worked over Autolite 2bbl off a 429 Merc. Man that thing would pull down the straights!

Jack Meoff · Jun 27, 2012

I wish I had the coin for one of those slant builds you did.
Sure would be sweet in my Caravelle.

Mopar 400 2bbl

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