Not sure if this is too general a question, but thought I'd ask. I have a 426 hemi already built and in my car. I was thinking of taking to a shop to put it on a dyno. I plan to have them change to a solid cam and change the bearings, so I'll benefit from break in time too, but my question is about what does it cost to run/tune an engine on a dyno? I would imagine all shops are different etc. but $500? $1000? more? Thanks.

My last time was $150 per day here in Mich

Chassis or engine Dyno ?

Engine

It varies greatly. You have to figure 1-1/2-2-1/2 hrs setup and teardown time before you hit the key. Mr. P got a very good deal. Myself, I've only had my junk or friends motors on mine and I have yet to charge a dime. I just told them to supply the fuel and replace an egt probe if one failed. I've yet had to replace one. One of my friends motors was on for almost a week playing with the combo. Another was on about 3 days sorting it out.

$500.00 per 1 day session.

In the northeast, you can expect to spend $500-1000 depending on how long it’s on there.

Engine dyno time here in Oregon varies from $500.00 up to $750.00 per day.
Their are several machine shops that have engine dyno that will only dyno engines they build and do all the machine work on
I had my bracket car on a chassis dyno in Medford, OR last month for around a half day, we made 6 pulls on it and did some timing and jetting change on the engine. The dyno owner is a drag racer also and ended up charging me only $100.00 for that time and then came out to the local drag strip for the evening also to see my car run

I think I paid around $800 earlier this year at a top engine builder.

Thanks all, I appreciate the responses.

It is typically a full day or a day and half to get an engine on the dyno, run it and then pull it off. It may sound like fun work to some, but it really isn't. It is a lot of hot grunt work and it all has to be done correctly or else you can destroy an expensive engine in a hurry.

Asking about cost is fine but you really need to get one level deeper with your questions. Does the shop have headers that fit your Hemi? If not, do your car headers fit their dyno? If not then you'll need to spend another $500 for dyno headers. Which carb and ignition system are you going to use? The dyno shop typically will have a fuel pump, ignition system and carb that are known to work. If you drag your stuff in there you could add some time and money to the job. I'm sure everyone is going to shocked to hear that most carbs that people bring to dyno sessions are down on power compared to the dyno shop carb. Everyone thinks they know how to tune a carb but I've sat in on at least 100 dyno sessions over the past 20 years and rarely does a customer carb work great. The best approach is to use the dyno carb to create a baseline then try your carb to see how far off it is. Then spend some time trying to get your carb dialed in. But this approach adds a couple of hours to the dyno session so now your cost has gone up.

Other things to ask about is how much data will you get. Does the shop use O2 sensors? EGT? Airflow turbine? etc. It all depends what you're trying to accomplish. A street car probably only needs a basic run stand type of test while a serious race engine can benefit from hooking up all the sensors.

Andy is spot on. Although mine is setup for my use I run individual EGT probes and an O2 sensor along with an airflow turbine and automated weather station. I like to run the headers that will be used on the car and I have welded in EGT bungs with permission. I have a collection of various carbs but like to dial in what's going to be used on the motor. Using their carb and headers gives a more accurate account of what you can expect once the motor is in the chassis.
One Moparts member and dear friend brought his 512 street motor over to break in and tune. We fired it up to break in the cam, set the timing, and brought it up to 2200rpm. Right away it started leaking oil from the rear main and the A/R was Dead Lean. Shut it off and pulled the carb apart. It was a Demon Silver Claw, said he'd paid a premium to have to setup for his combo. Between the time he bought it and the time we dynod it the company had filed. Anyway once apart we found a broken drill bit still in the primary metering block. They left it in there and just drilled another hole next to it. The whole carb was pretty much junk. We threw my 850 Holley on it and it was spot on, the motor was using 780cfm so I recommended a 800 Edelbrock as it was a street cruiser. The rear main leak was caused by interference between the rear main ARP studs and the seal retainer.
In conclusion, look around, ask questions, try and find one where you can use your own headers and carb.

is that a 8 hr day ?

it depends on the dyno operator and owners
I've paid for a complete day when a part failed on the second pull early before noon and I have also paid for a day that we spent 12+ hours on the dyno making changes not including loading and unloading it on and off the dyno

Good post by AndyF.

Do they have Mopar flywheel, bellhousing, starter, headers, etc. And will you do the tuning, or them?
FWIW, I paid $500 basic dyno session and they did all the work (tuning, valve lash, carb & spacer swaps, etc.) In addition, I bought some carb studs and carb spacers to try from them.
They asked me to drop it off the day before so they would mount it all up, and I showed up the next morning to begin the dyno runs. I took it home that same day.
They had race gas, but I brought some 93 pump to use after initial pulls with their carb and race gas. Did back to back with my carb and both fuels.

I recommend starting with their proven carb, and swap yours after initial pulls and break-in are done.

Jim

Flywheel is a good question and so it bellhousing and motor mounts. It just comes down to a question of if the shop has everything needed for a Hemi or not. Most shops are not going to have the ability to run any engine. The Hemi has unique front motor mounts so if they haven't run one before they might need to build some brackets. If your Hemi has an 8 bolt crank then you'll need to double check to see if they are set up for that. Most shops are going to have the Mopar 6 bolt setup but they might not have an 8 bolt adapter.

You'll also want to ask about the water pump. Are you going to use a belt driven water pump or do you have electric? They will want you to remove the thermostat if you have one. I had one shop that required an input shaft bushing in the crank so their driveshaft would fit properly.

Thanks again all. Sounds like the best thing to do is go down there and talk to someone. Tell them what I have and what I am looking to have done. See what they say and what they will need to do the job.

Something that I have noticed speaking of carbs is that the 440 for my Plymouth will run about 3 jets rich on the dyno from its fastest times. I figure it is from the sealed air scoop forcing air at the carb?

Your results are not uncommon
As the professor Warren Johnson has said many times, we don't race dyno, do we
I've learn to get the tune up close on the dyno and then finish tuning that motor in the car it will be raced in at the track it races on I use the spark plug and time slips to help get me the best results at the track, when we have the time needed to get it done