Have a 78, 440. All stock except for a set 0f 69- 906 heads and 770 holley avenger carb.

I am looking to see how much it would cost to get that motor to about 400HP.

Or is it better to just buy a crate motor.

This is just a street driven car/ daily driver. Not looking to go crazy, just get more power.

Thanks

Pretty simple to get 400 HP out of your 440, should be no need for a crate engine. If the engine is fresh just put a good dual plane aluminum intake under your 770 carb, install some headers and good free flowing dual exhaust, good ignition system and you should be pretty close to 400 with maybe a little extra, good luck.

$5,000.

Do you want a rebuild or do you just want to mod what you have to 400 horsepower?

The 78 440 will have the smogger low CR pistons. Your actual CR will be around 7.8:1. Now if the short block is in good shape, you can get 400hp out of it, but it will be less streetable than a comparable 440 with better compression.

$3500 with a little luck and you doing the assembly.

If your motor is sound i.e. not burning oil and quiet, a simple cam change and a set of headers should easily get 400 HP. Must find a good cam for a low comp motor though....

The motor was a replacement motor. It runs fine and only has about 3000 miles on it.
Is it worth rebuilding to get it up to 400 hp or just better to buy a crate motor?
I would like to get more compression, and better heads if thats a better route than mickey mouse the motor.

The comments are all over from simple $500 to $5000.

I wouldn't be able to justify rebuilding if it's only got 3000 miles on it. If all else is running well there are better places to spend your money. I wouldn't even take a cylinder head off.

For a low CR build with stock heads I would find a used edelbrock CH4B intake. Good dual plane intake, and with stock heads IMO a better choice than an edelbrock performer RPM. Buy yourself a set of cheap summit headers, but spring for some decent gaskets. For a cam, I would take a look at hughes "whiplash" cam for 440. They ground that cam to make power while maximizing cylinder pressure in low compression 440's just like yours. Then do yourself a favor and do your torq converter. Don't leave a stock converter in there, buy something that will stall to 2800-3000rpm. This will help cover the bottom end torq that the smogger piston 440's are soft on. I haven't heard good things about the street avenger carbs but no real experience. Also you will NEED to recurve your distributor. If you're not going to recurve your distributor, you might as well not even unbolt the intake from that 440. Dialing in your spark advance will make or break a low CR 440. Also what's your rear end gear ratio?

Why the focus on "400" horsepower?

Its just a number.

There are soooo many things to consider; that's why you're hearing $500 to $5,000.

It all depends on what YOU want to do with the vehicle; not just that you want "400" horsepower.

The whole thing has to be a plan; you have to match cam, intake, carb, stall converter, gear ratio, and tire size all to what you want out of the vehicles purpose.

Is fuel mileage important? Is high rpm important? Is 75 mph for freeway driving important?

So my point is there are many things you can do to a vehicle to make it perform and FEEL more powerful and like it has more horsepower, without really adding horsepower IN the engine. You shouldn't focus on wanting "400" horsepower as much as doing the things to make it perform "better" - for whatever it is you're looking for.

Change your gear ratio.
Add an intake manifold and carb.
Add headers.
Add a bigger cam.
Change heads.

If you want to change compression more than what you can do with heads and thin head gaskets, thats when your money will be falling out of your pocket. Like the poster above said "$3500 and you assemble." And why I said, "$5,000." Getting into an engine for a complete rebuild isn't cheap.

I'm just offering some advice and points for you to think about. I'm not critiquing or judging you or anyone else's comments, just trying to help.

I'll dare to say it.........

get some closed chamber 516 heads, shave them .060, add the 1.74 exh. valve, invest in a cheap harbor freight die grinder, bowl port the heads with a few select stones, add a MP 284/484 cam, a used aluminum dual-plane (like a CH4B, Weiand or Perf. RPM), your carb, headers and an easy 400+ ponies with moooocho torque at 2400 rpm and up.

Far & away less than a crate motor or $5000.

Ok, the car is a 70 challenger with fast ratio steering, so not sure if headers will fit or not.
The car is a standard.
Rear gears are 3.55

The reason I said 400hp is just to clarify that I'm not looking for a stroker motor, just a point of reference. Mild build.
Since the motor is in great shape, I was hopeing to get better response.

Are the 906 heads a good option for this motor or would bolting on different heads make a big difference?

Read this:

http://www.hotrod.com/how-to/engine/mopp-0805-mopar-engine-build-guide/

If you have access to a compression gauge you can save yourself (and us) a lot of time. Write down what compression you have in all 8 cylinders and post that. If you can check the engine vacuum then even better.

If you have low cylinder compression then there are not any "cheap" fixes to get you to 400 hp. If you have decent compression then some bolt on parts probably get you there.

3,000 miles, it's just broke in. A cam, intake and hedders would wake it up.

Maybe this will give you a few ideas. We invited the neighbors over for a 'dyno day' at the shop and made a few changes to a 7.5:1 compression 440 over about eight hours and made a dyno pull after each change. It wasn't designed to be a perfect combination, we started with stock 906 heads and used parts we had laying around.

Low compression 440 dyno test.