Been a really long time since ive posted anything on here or anywhere for that matter and im finally finding interest in my 65 Coronet again but now i have acquired a beautiful 871 Mooneyham blower complete setup for a 440
I am new to the blower world and havent ever ran one but find myself very intrigued by this arrangement of Mayhem
Im going to start from the shortblock and work my way up .
Ok that being said for a street/strip car and im talking more street than strip how long will a nicely prepped stock block live keeping the boost at 10 psi MAX theoretically
Am i just wasting time and money ??
Plan on a forged 440 crank and Manley H beams and Arias Dished pistons
Indy SR Heads Cam is going to be decided by Dwayne Porter
Any Input or ideas will be appreciated Thanks Matt

A girdle is a must. I suggest the whole rotating assembly from 440Source if you don't have it yet. Opt for the best bolts throughout.

Buddy of mine had a stroked 440/493 in his street car with an 871 on pump gas...Car was wicked! Easy horse power, tire frying mayham.

Who Makes a decent girdle For these things now days ?

Sell it and go with Holley EFI!

you will be much happier...

my 2 cents

You would be a lot better off starting with a 400 block, that blower at 10 lbs. of boost at WOT will probably break the main webbing in any of the stock 440 blocks, girdle or no girdle, in very little time
I've seen stock type 440 blocks that are not supercharged break the main webbing above 700 HP
Or better yet spring for a after market aluminum or cast grey iron block, if you can find and swing a deal for either one
IHTHs

Believe me i have thought about that with alot of consideration LOL
Ive done about everything ive ever wanted to do to cars but the blower has been on the bucket list for many years and i own the silly thing now so i will try it and waste countless dollars and then change it out for something more friendly im sure, just like i Tried A Jerico 4 Speed and i would give it a 10 on the fun scale but also a 10 on the miserable side of reality LOL

Cab ....Who has an iron block that is decent now days
I heard Mike and the gang at Muscle motors has something going on but dont know if its takin off yet ??

MM is closing up according to them earlier this year, several other vendors, Ray Barton, Chicago Connection and several others are suppose to be getting those blocks as they come out of the foundry and machine shops
I'm going to wait until all the bugs are worked out of those blocks before buying one
Bob George racing and other Indy dealers are able to get you a good Indy wedge, both high deck and low deck, aluminum block

Stock block,,,,,,,671,,,,me thinks 5 or 6 lbs of boost and 7.5:1 and run on pump gas!

I would go a slightly different direction. Stock stroke, 7.1 rod, aluminum main caps and girdle. Bigger cubes won't matter. You will have more than enough torque and power at 10 psi boost. Longer rod ratio will be easier on the stresses thrown at the block.

BCR girdle and maincaps, that 8-71 significantly underdriven on E85 at 9:1 compression. S/F....Ken M

with Mike here. Alcohol is super friendly here. That much boost is going to require some expensive gas and the tune up must be perfect. With gas, the lean or fat conditions are a LOT harder on a girdled stock block. With alcohol you can add more compression for efficiency as well.

I guess I will see what happens on my 440 with 30 over pistons. 8-71 running 11 pounds currently under driven. I do have two fuel cells in the back though. One for pump gas and one for AV gas. Also running a MSD boost retard box too so I can dial timing out. See what happens.

I ran a 6V=71 on a stock 340 block for over 20 years at 13lbs. Even detonated 2 sets of pistons learning to tune. Never hurt the block. We also run a stock 360 block/cast crank at 21lbs. A buddy has run a stock 440 block, iron heads, 8-71 on alcohol to 5.60's in the 1/8. A sensible tune , thick crown pistons it'll be fine for mostly street.
Doug

440Source...

I love Roots blowers, the main advantage is the Instant torque at any RPM, no need to have any sort of high stall converter. The key is you are very seldom going to need to go to WOT and maximum RPM but if you do you want some sort of boost retard which is really your safest bottom end protection.

Very good cooling is also essential, you may be surprised how much heat even an underdriven GMC style blower builds, those ribs are there for a reason. I would probably limit the boost to maybe 7 or 8 pounds which basically increases your effective displacement another 50% in terms of torque production.


I would like to do a 470 low deck with a 2.200 journal 3.90 stroke and a 6.800 BBC rod but to use an RB manifold you would need to run some sort of Stage VI head....so to run an RB I would still do a 3.90 stroke but with a 7.100 BBC rod. A girdle would be addeded insurance but for me strong but lightweight internals are essential because the RATE of ACCELERATION of the crank under load goes way up in a boosted motor.

For a blower set-up I like to run another 1/2 a thou of P/W clearance with the finish hone over the piston MFG spec with a fairly long skirt, piston rattle at TDC and excessive rock at BDC under load is what you want to try to minimize at all costs. Run a BIG radiator and aluminum heads and to save the bottom end, keep the max RPM down under 6000. The problem with boosted motors is they make so much power it's easy to overrun the safe zone of the block because the power doesn't percievably drop off in terms of the Seat of the pants, however, even though you don't feel it you are still transmitting all those high torque + High RPM stresses into your block. Methanol/water injection is also a great investment, keeps the blower cooler and the tune safer.

An 8-71 would probably run at least 10-15% under-driven. key is to incorporate some boost limiting is not as easy to accomplish with a wet (fuel through the blower case) system, if all the fuel was injected below the case (as in a modern OEM like the hellcat) it would be easier to dump excess pressure. The thing to remember is you only boost when you give it enough air to make boost so in a way, limiting the carb max CFM can also keep your bottom end safe. But I would do this with a large carb with a throttle stop rather than too small a carb for the street. But in safe race tune with race gas you can always back the stop off.

Have fun! I'd love to do another Blower motor someday, I always had a blast.

1 to 1 drive is only about 4# on a 440

Clanton,

only 4 psi? Is that right?

I think it's more than that (but correct me if I'm wrong) because if you remember the 71 series Rootes was designed for a Detroit Diesel....which are 2 strokes. And the supercharger was required just to get enough air into them, I only know this because I worked on and learned a ton from working with big Deisel mechanics as a 'young-un'.

So when you put the blower on a 4 stroke of the same discplacement, each revolution of the blower is packing only 1/2 the cylinders/displacement PER REVOLUTION... so the boost is actually proportionally higher. I think that's how the early Hot-rodders figured out how they could make them work

They used 6-71's on 426 Hemis for decades at close to +/- 1:1 ratios and we know it will definately make more than 4 psi of boost. There are pretty generous efficiency losses between the seals and the case, not to mention air density losses from heat but still the displacement calucation was based on the GMC/ALLISON/Detroit Diesel standard 71 cube cylinders. I thing there was a 53 inch Cylinder as well, a lot of early smallblosks ran 4-53 blowers

i would think an 8-71 on a 440 could be significantly under-driven on the street and easily make big boost.

One of the west coast fastest 10.5 outlaw racer has said more then once that high boost pressures are a failure of head flow or some other related failure on the motor, in other words make sure the motor can handle the airflow in and out
The better the motor, the better the results

Rolled around the idea of doing this in my Duster for Nostalgia class I run. If I were to do it, I was going to build a low deck 383 stroker with 440Source parts & girdle at 493 cubes and an 871. I can tell you, it would be a blast, but I worry about the heat between rounds. As we run, the rounds get quicker. On pump gas NA, its not an issue, but on Roots, I am thinking it would add a bunch...Been kinda thinking an F1R procharger on water injection would be better for heat.

Dragula brings up a good point! Anyone run one of those "Superchillers"? Like they have on bada$$ boats? Wouldn't coolant temp. even be enough to make more power or stay in the game longer? Add extra capacity to the cooling system too!

This is wrong. My 8-71 currently is under driven by 5%. I can go from 20 inches of vacuum to instant 11 pounds of boost by flooring it. Feels good too pulling hard. Do not see me needing to over drive it by swapping the pulleys. A race car driven on the street but power and giggles when I want it.

I built a vintage 354 blown Hemi's 10 years ago.

Stock block and heads... Venolia pistons...8-1, 8 lbs. boost, stock rods bushed with good bolts... Si stainless valves... stock rockers rebuilt... Clay Smith cam...very mild with a 113 lsa...525 lift... 240-ish duration (the blower mellows out the cam a bit). I ran an old Carter 750 single. Nicely built engine with good parts and machining.

You don't need a girdle, aluminum heads, dual 850's, fancy rods or a mega crank IF you keep the boost down to 8lbs. and keep your hoof out of it. You can have a very nice DD with good fuel economy and loads of driveability.

Now if you want 4 mpg, an uncontrollable idle, gas dripping from the exhaust, overheating in traffic, etc. then go all out. I didn't want that...

There are thousands of blown factory built cars running hyper pistons, stock rods, etc. getting 100,000 miles or more without issues.

I also helped a friend build one of these. It was a 354 with a tunnel ram and a blower on top of that. Cost a lot more than doing a blown wedge, and at the end of the day, only made a shade over 500hp...Lots of torque and reliability, but was a big disappointment. Especially with today's wedge heads where 700hp pump gas NA is no problem.

Yes I run a Blower shop intercooler.[15yrs]

The boost recorded is dependent on many things,You got 11# I got 4#.

Boost is a function of back pressure(and heat expansion). A set of worn out 906's is going to make more boost but less power than a set of B1's at the same drive %. S/F....Ken M

If its a race only deal, run mechanical injection on alcohol, and there won't be a heat issue. That's assuming alky is allowed in your Nostalgia class.

It won't cool down the blower itself. They get hot.

Yeah, I see that. Good point. Boats run cool lake water through them so I see where that would really help cool things. It makes better sense to cool the air before the blower. Heat rises right? The cooler beneath the blower is really helping the engine more than the blower.

Dave

With cooling the air before the blower the problem is now the air will get hot from the friction of the vanes. Detroit 8v92 is a good example also. Inter cooler is below before air enters engine after turbo. Another example would be a GMC Typhoon or Syclone as how they are inter cooled. No room under hood to clear so they had a good idea how to fit it in. You need to cool air after the turbo or the supercharger.

When you compress air it heats up and expands, roots type coolers mounted under the blowers can block the air flow into the motor so you see limited gains on the dyno or track with them
I think alcohol injection into the top of the blower would help cool down the intake air temps under the blower and make the motor make more power

Being on the street helps since things don't generally break until it hooks.

The track will be the challenge on breaking things. Run a small narrow slick with a ton of wheel speed of the line (almost spinning) and it might live a little longer, maybe.

Throw a good pair of E85 Dominators on it, and that'll help keep down the temp.

I like the tuning of EFI for sure. The trade off though is a complicated mess of one thing fails, you're dead in the water, or it taking charge of things from faulty information from a fouled sensor ect.

Carbs are what they are, but if I had to put a blower motor in a plane, and ride in it myself, I'd never use EFI lol.

Here is mine with the intercooler.

Too cool Clanton! Love it!

Clanton

Looks good. I will put one up of mine but just noticed I never took pics of once it was done but only during assembly. Take a pic tonight. On the upper radiator hose too I found one that fit without having to use a flex tube. Was off a Ford if I remember right? Will see what it was off of and the Napa part number.

Clanton,do you think the intercooler you use works better than W/M?

DSCN3008 copy by todd, on Flickr

Water outlet on the block I used a short straight outlet

Hose I used I can't find number. I have one written down but not the correct one. Might be one I was seeing if it fit and wrote it down. Will see if I can find it out when I take car out tomorrow stop by Napa and look for same one.

For me I think it works better but I only used a base kit from snow.[2x 625 ml,min]

Thank you for looking for the part# and the pics,Very nice!

Clanton

Hose is off of a 1998 Dodge 1500. Napa #8726.

You will need to shorten it towards the radiator and a little on the height to clear the blower snout. After that you would think it was supposed to go there.

I think the hose for a late 80's Lincoln Mark VII 5.0 will work too, it did on mine

Thank you for the part # both of you.