A couple questions about supercharging a 440

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Dguyski

Dguyski

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Hey guys, I'm planning to supercharge the 440 in my '67 barracuda, and I've got a couple questions before i go ahead and start ordering parts. First off, how much could the stock crank handle with a 6-71 or 8-71 blower? I'm assuming it's cast because i don't know the serial number on the block, but i know the bottom end is Indeed fresh with about 500 miles on the new bearings. I will be installing a set of forged rods and pistons so I'm not worried about that, I'm just hoping i may not have to pull the engine to swap the crank. I'm shooting for 600hp, and I'm sure that's easily achievable with a blower and a proper tune job. Would a stock cast crank be up to the task if the rods and pistons are forged?

Also, i am going to install a hydraulic roller cam, the specs are 243/251 @0.050" and 0.560"/0.565" lift with 110 lsa. Would this cam work alright with the blower? Or would it have too much overlap? If it will at least support 600hp I'll be fine with it, I'd prefer to have a choppy idle if at all possible. Thanks for any advice in advance, I've never built a forced induction engine before but I'm looking forward to it!
 
I think you'll be fine with the cast crank but there are other considerations:

a) Cast cranks are externally balanced so you can't use a blower crank hub if you want to. Stock balancers aren't recommended (SFI rated are) but, if you do, the blower pulley registers are a different size and bolt pattern.

b) Double crank keys (not required) are recommended. That involves broaching another key-way in the crank snout.

c) Blowers will smooth the idle slightly of an otherwise 'choppy' cam. Blower cams have a wider LSA but the 110* will work fine. Just means you'll blow a little power out the tail pipe. Will you notice on a street car? No. Might help it run a little cooler too. BDS even recommends an LSA of 110* in a build like yours.

d) For a street car, no need for custom low compression forged pistons. I'm using Speed Pro L2266F for around 8.5:1 static compression. Snappier response when you're just cruising around (vs some ultra-low compression number).
 
What 70Duster440 said is great advice.

I wouldn't worry about cast crank at 600 horse. And yes that should be easily achievable. That cam would work fine. You're not gunna be putting crazy boost through it anyways.

My suggestion would be to go with the 8-71 instead of the 6-71. You will be able to turn it slower to make the same/more boost. Which is always a benefit. The slower you turn it. The less you heat the intake charge. The less chance of detonation you will have. You don't mention what heads you have. But they will also play a significant part in detonation reduction.
 
Thanks for the advice guys! I have stock cast iron heads at the moment, I'm not sure what the casting number on those are either but i was debating whether or not to have some serious work done to them or if it would be worth getting a good set of aluminum heads. I've looked at some edelbrock Victor max wedge heads with 290cc intake ports and 100cc exhaust ports, and some trick flow specialties with 270cc intake/74cc exhaust. It would cost me double for the aluminum heads what it would to have my local engine builder work the stock heads, plus i would have him go through the new heads with a valve job and make sure everything is up to snuff, so that would add to it. Plus i wouldn't be able to run stock valvetrain with the aluminum heads according to the info I've read about each one. But, i understand in the long run it would be worth it if i decide to turn up the heat and make more power. I really appreciate the advice, I just want to make sure she lasts!
 
If you have the money to spend on heads, valve train, and all that then go for. But one of the nice things about a blower is that they'll make up for deficiencies in other areas. You WILL see very noticeable gains in HP and torque with stock heads. It might not be ideal but it will work. Worse case you build pressure in the manifold you can't use because the heads are the bottleneck. But unless you're racing and you need all the trick parts to make every 10th count, I think you'll still make more power than you can realistically put to use on the street. The fact is, you don't make boost until you wind it up with the throttle wide open, under load. Most of the time you're not doing that. Still, at idle and cruise, it is forcing a charge into the cylinders and will very responsive.

If you want it to live you just need to control detonation. Forged pistons, good pump gas, and sane boost levels (watch your dynamic compression ratio) are where to start, IMO.
 
Like 70Duster440 mentioned. Blowers are GREAT for making up for deficiencies in other areas. You can have a shitty cam. With shitty flowing heads. With shitty compression. Drop a blower on it. And still make 500+ horse EASY.

The other nice thing is the throttle response. You'll have gobs of torque down low. It'll roast the tires everywhere.

For reference here's a boost/compression chart and blower drive chart:
88252d1088983437-blower-pulley-size-charts-chart.jpg


Compression-Ratio.jpg
 
My opinion, build the best bottom end you can afford while you have the engine out. It doesn't have to come out later on for upgrades. The best bottom end for your plans may very well be what is in there now. In my case, my builder put in a used Callies crank from one of his Top Fuel friends. Your cam sounds fine. Not sure you'll get the lopey idle you want because the blower will tend to smooth it out. Doesn't sound like you want to build a ragged edge race engine. 600HP sounds easy with what you are describing. In my case I could not keep the wiper motor in with the 8-71. We had to recess the fuse plug box. Had to take out the puller fans out and put in pusher fans in the front of the rad. There just wasn't any space left to do otherwise. Used a front engine plate instead of mounts. My engine has CNC'd Edelbrock heads. They will be fine until I can come up with some scratch for something more exotic - no rush. I think cast iron heads would work fine, but that they would tend to be a bit of a heat sink after awhile. I put in a 55GPM Mezerie water pump, no t-stat, and a 3 core aluminum rad for cooling. Maybe try and figure out in advance what size pulleys (teeth) you want to run. Pick what carbs you'll be using.You'll probably have to upgrade the fuel pump, regulator and supply line. You'll probably need a new throttle cable.Transmission may be a weak spot, depending how often you see how much boost you can make. Deep sump, rear mounted cooling fan for trans fluid. U-joint upgrade. Check out the differential. You'll need to modify the hood (if you are going to use one). Nice open exhaust system. You can go without doing any mods, but I encourage you to think of it as a package deal, not just slap it on and hope for the best. No matter what you do, like Lustle said, you will make power and I think 600 is a conservative estimate. You will be amazed.

thumbnail_IMG_3607.jpg Supercharged Duster.jpg
 
I found the stamping number on the block and the casting number on the heads, it's a 1978 440 with a cast crank and 452 heads. Now a background on the car: it's in a 1967 barracuda that spent most of its life as a drag car. It has a 8 3/4" rear end with 4.11 gears and moser axle shafts, the transmission is a 727 with a manual valve body and some beefed up internals, though I'm not sure what parts. I currently have a small cam in it, .465/.488 with 294/303 and a 112 lsa. I put a weiand hi-ram on it with 2 600cfm holleys, and it is awesome. But my wife of all people gives me sh*t about having things sticking up that aren't on a blower lol and i see that as an excuse to supercharge it, but i don't want to pull the engine if i don't have to. So pistons and rods are as far as i plan to dig into it. If i can run it around 600 hp on pump gas i think I'd be most pleased
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You're changing pistons, rods, cam, etc... without pulling the engine? That just makes no sense. You're making the job about 4X as difficult as it needs to be!
 
The less i have to dig into it the better, I'll only be spending more money the further i go, be it by necessity or by my sheer desire to buy new things. If i can achieve 600-ish hp safely with the rotating assembly and cam that are in it then i will leave it alone. The engine was rebuilt just before i got the car, I'll have to dig through the receipts to see who did it but everything is stock spec except what i mentioned before. If the cast pistons can handle the blower at a modest boost level without detonation then i guess I'm just over thinking it.
 
I agree with Bob, no need to go in the block as long as your static compression ratio is 8.5 or below. The cam is a little tame but will suffice. If you don't plan on more than 6 or 7 lbs of boost then you are good to go. I would change out the rear gears to maybe a 3.23 gearset. You will have gobs of torque to turn them. Spend your money on cooling and carbs. Look around you can usually find a used blower setup fairly cheap. Good luck, blowers are a blast.

Jack
 
As Coyote Jack stated blowers are a lot of fun ! I built a 1972 Dodge Colt with a 440 and 6/71 in late 1986 . I used the stock steel crank with the LY rods , just changed out the rod bolts to ARP . Used stock steel heads with a small amount of hand porting by me . Cam was the old 509 DC cam . For carbs used 2 750 DP set up by BDS . Back then they blocked the power valve and over jetted to make for the lack of the power valve .
Now they have manifold ref . power valves that take a signal from the manifold and will run much better . Blowers will not give the carb a signal to add more fuel , by getting the signal from the manifold the carb will open the power valve and supply the engine with more fuel . I will add pic's of a carb .
Just to let you know blowers are cranky , when starting up a cold motor , BDS recommends to pump the gas petal 3 times and count to 10 slowly and the crank the engine , when it starts try to keep it running but if it tries to stumble and cut off DO NOT pump the gas it will back fire and could damage something . I helped one of my friends build a 1971 Demon with a blown 440 , He called me and said that he could not get the engine to idle , looking at the carbs I saw that the rubber plugs on the bottom of the carbs were gone , I put my fingers on the 3 missing plugs and he started it up and it would idle , removing them it cut off . I asked he it it back fired and he said yes . So be care full when starting a blower motor up when cold .
Next be sure you put a large exhaust system on it , on my Colt With a lot of limited space I used see thru glass pack mufflers 2 1/2 inch . Power was good but take em off John Force Burn outs were unreal .
On the 1971 Demon we used a 8/71 blower and ran into the back of the blower hitting the wiper motor , I think that the car had a 2 speed wiper set up , If I remember straight a 3 speed wiper is a little different and when installed it still hit but with a little work with a file on the edge of the wiper gear box we got the needed space to fit the blower , just sealed up the gear box with a little gasket sealer and painted it .
Now for the good stuff , the Colt would run 0 to 100 in 7 seconds in second gear , would break the back tire loose in third gear at 35 mph when rolling , Would scare the crap out of your passenger . I used a 4:10 gear and a 3000 converter . Would idle at 750 rpm and had a hell of a lope .
I am now building a 66 cuda with a 472 crate hemi with a 6/71 and one 1050 cfm carb .
I posted pic's of the Demon , 1050 cfm QF carb with the fitting that goes to the manifold and a pic of the 472 Hemi in the car , Still looking for pic's of the Colt . Hope this will help you with your issues .
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demon 001.jpg
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What are you planning on running with the engine set back so far. That looks like it will be set on kill right from the get go. Thanks for the pics.

Jack
 
Coyote Jack said:
What are you planning on running with the engine set back so far. That looks like it will be set on kill right from the get go. Thanks for the pics.

Jack
Click to expand...
Jack , look up on FABO and find Old Man's 66 Cuda Funnycar build . There are posts and pic's on the car . It's an altered wheelbased stretched nose funny car for the street .
 
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