Aluminum vs Cast Iron bell housings

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64whiteghost

64whiteghost

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Whats up guys.

I have a question.

Im building a 1964 plymouth valiant. 340 450hp. 4 speed. 8 3/4 3:73 posi.

Im curious if there is a difference between the aluminum and cast iron bell housing. ?
 
Assuming you're talking four speed bellhousings...
Cast iron is single pattern only (4 speed, 10 1/2 or 9 1/2 inch clutch, 130 or 122 tooth flywheel depending on the engine they came on), aluminum is dual pattern (3 and four speed patterns, all used a 130 tooth flywheel with a 10 1/2 inch clutch). Aluminum could also have the large bore for the OD transmission's bearing retainer.
They all use different pivots, clutch forks, and ballstud brackets dependent upon their original application, but those parts can be swapped for correct ones for your use.
 
Cast iron is stronger and heavier. Aluminum is weaker and lighter.
 
Mopar64340 said:
Ok so aluminum would not be suggested for a 450 hp motor ?
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In terms of strength from a clutch explosion, it won't matter. If you want something for strength, scattershield is the way to go.
 
Do not use the 4 bolts that held the gearbox to the iron bell, they are too short for the aluminum bell.
 
Mopar64340 said:
Ok so aluminum would not be suggested for a 450 hp motor ?
Click to expand...
Clutches and cast iron flywheels have been known to explode. The higher the torque, horsepower and rpm, the higher the risk. A scatter shield helps contain an explosion much better than a steel bell. An aluminum bell does nothing. A Kevlar blanket over a scatter shield is even more protection. A steel flywheel is much stronger than a cast iron one. Don garlits lost 1/2 his foot to an explosion. Don’t loose yours.
 
A scatter shield will most likely require sheet metal surgery on the trans tunnel in an early A body.
 
Private Idaho said:
A scatter shield will most likely require sheet metal surgery on the trans tunnel in an early A body.
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Choose wisely, an Ansen if you can find one. Maybe a quicktime, but I have not tried one in an early A. Best insurance is an SFI pressure plate and flywheel.
 
66fs said:
Choose wisely, an Ansen if you can find one. Maybe a quicktime, but I have not tried one in an early A. Best insurance is an SFI pressure plate and flywheel.
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A Lakewood definitely requires surgery; an Ansen less so, if I remember correctly. I agree the QuickTime looks promising, but have not had the opportunity to try one either. (Don't you feel like we're dating ourselves by even remembering Ansen "Blow-Proof" bellhousings??:))
 
Not much difference when comparing the factory cast iron vs. aluminum. They are just good for restorations or low hp/rpm street use. Blew stock iron one years ago and it was a mess, pushed floor up about a foot and ripped through. Like said above, any real hp, and especially if on slicks, or I suppose drag radials nowadays, get the aftermarket shield.
 
Professor Fate said:
A Lakewood definitely requires surgery; an Ansen less so, if I remember correctly. I agree the QuickTime looks promising, but have not had the opportunity to try one either. (Don't you feel like we're dating ourselves by even remembering Ansen "Blow-Proof" bellhousings??:))
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I still have an Ansen to go in the 66 next engine I try.
 
Outsder said:
Not much difference when comparing the factory cast iron vs. aluminum. They are just good for restorations or low hp/rpm street use. Blew stock iron one years ago and it was a mess, pushed floor up about a foot and ripped through. Like said above, any real hp, and especially if on slicks, or I suppose drag radials nowadays, get the aftermarket shield.
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I ran the 71 340 bellhousing and flywheel behind a 273 in a 64 Barracuda that would run to 6,500 rpm easily and was there often. They came from a Duster that was drag raced most of it's 100,000 mile life, slicks and all. The stories are enough to scare you though, and yours is first hand knowledge.
 
Ya it's not a problem until it is. A few years later I had another like failure, but with all the SEMA stuff, as my racing effort was more "serious." This time everything was contained, so I can definitely say the shield works.

I think I still have box with bits of some of my blow up parts, clutch and engine pieces; I used to spin them pretty high and once in a while some failed. That said, I run a stock BH on my '70 and have no concerns, though it's strictly a street car and I would never put slicks on it, rev it above 6,500, and drop the clutch like when I was racing years ago. So I guess it all depends on how you are going to use your car, but to the point, my experience, is that neither stock BH is significantly safer if there is a failure.
 
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Flywheel for sure on the first one, clutch housing on later one, in either case, a lot of weight to be throwing around. Lost a few 8 3/4"s and driveshafts before I switched to the Dana. The scariest failure was even later when I was making some more significant power, going into 4th gear at 120 something mph, and it broke all four ears off the trans case and the trans rotated and destroyed various other things.
 
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