Is it possible to build a big block for great performance and good economy?

oldkimmer · Jul 9, 2020

Way more efficient. And better time. Just better all around. U can have a 4000 stall or even a 5000 stall and drive it in the street no problem. Acts normal till u stand on it. Google Precision of New Hampton. Kim

Bad B-rad · Jul 9, 2020

I do not rebuild transmissions for a living, so I dont have experance tearing into 100's of trans,but any small block 727 I have encountered have had drums that took 3 clutches, and had maybe 4-8 springs vs the big block 5 clutch and 8-12 springs.
I have had big block with 4 clutches that will except 5. I am talking the thick/factory 0.95 ones not the thin 0.61 ones I have never got into using the thinner ones, or any roller bearings, or aluminum drums. Again I just done stock rebuilds.
EDIT: Stock style but better seals/bands/clutches

Bad B-rad · Jul 9, 2020

I had a TCI 3500 stall behind my 440 about 15 years ago, biggest I have ever gone.
I loved it when WOT, not so much for daily driving to work, IMO

Bb70charger500 · Jul 10, 2020

Big block and good mpg don't go together!
That being said
My 64 Chrysler 300 has a 413 in in .
Not a power house but say 300+ hp under 350 and it can get 20 mpg
Never looked at rear gears but I'd assume it's highway gears . It loves the highway!

If you want a ground pounding big block I would ignore the term mpg!
If you want mpg I would ignore big blocks !

Now me my daily drivers both get 12-15 mpg ones srt8 6.1
Other is a f250 king ranch
So anything over 15 is great to me!!!!!
Long trips I take wife's car 25-28mpg or the 64 300 at 20 ish

Along time ago I had this great 74 charger 318 904 8 1/4 I swear that car got 28 mpg all day long ! I drove that car everywhere but God was it a slow charger

Bad B-rad · Jul 10, 2020

"Hang on that is nonsense. If a 727 took 35/40 hp, no slanty in the world could turn it, and there would never have been thousands and thousands of taxi-cabs that ran them." Quote - AJFORMS.

Here is one of the posts I read, found on MOPARTS.com
Info from TCI,
1991 issue of Hot rod Mag.

powerglide....18 hp
904...........24 hp
c4............24 hp
727 ..........45 hp
400 ..........45 hp
c6.............63 hp

Bad B-rad · Jul 10, 2020

AVG HP required to operate:

These numbers are from an article in Car Craft Magazine.

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp

Paul_G · Jul 10, 2020

Power loss through an automatic trans is something to consider. So is power loss through the rear differential. I have read that the Dana rear ends in the 6 pak and Hemi cars consumed more power to operate than the 8 3/4" do. So it is a trade off, efficiency or strength.

Bad B-rad · Jul 10, 2020

Paul_G said:
Power loss through an automatic trans is something to consider. So is power loss through the rear differential. I have read that the Dana rear ends in the 6 pak and Hemi cars consumed more power to operate than the 8 3/4" do. So it is a trade off, efficiency or strength.

Yes sir,
I have heard that an 8 3/4 can handle a lot more power then people think.

If you were building a big block for power and economy, then everything you do to save weight, and reduce any parasitic loss would be a great start.
Like use of electric fan, and water pump, maybe even manual steering.

I wonder is there is any (beneficial) weight savings using a B engine vs RB, if someone was going to build this theoretical engine.

Bad B-rad · Jul 10, 2020

I guess we would have to set some basic parameters, as far as we dealing with just the engine, and limited to the stock transmission, and rear end, or any trans and rear end.

GrabberOrange69, had a great simple idea, worth expanding upon, a 250 shot of N2O.
If you built a engine from the start, knowing your going to use 250 shot of gas, It may make the engine side of things a bit less complex.

Is it possible to build a big block for great performance and good economy?

oldkimmer

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Bad B-rad

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Bad B-rad

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Bb70charger500

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Paul_G

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