New Member - 1967 bel air - Impala Tech
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post #1 of 11 (permalink) Old 07-12-2019, 06:08 PM Thread Starter
Join Date: Jul 2019
Posts: 10
New Member - 1967 bel air

Hello all. Happy I found these forums. I own a 1967 Bel Air I picked up about 2 years ago. I've already installed air ride, and replaced the master cylinder and brake booster, and installed disc brakes in the front. The body is perfect, and it has 41k original miles.

It has a rather weak inline 6, and a powerglide but I am working on a 454 for it, and not sure on transmission yet.

I am looking forward to working on it, and will certainly be searching this forum for information.

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post #2 of 11 (permalink) Old 07-12-2019, 06:12 PM Thread Starter
Join Date: Jul 2019
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Here is a quick pic of the car prior to air ride. When I bought it, the previous owner had cut springs on it.
62BillT likes this.
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post #3 of 11 (permalink) Old 07-12-2019, 06:42 PM
Join Date: Jan 2006
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Welcome to the Team!

You will need a TH400 or 4L80e to hold a big block. PowerGlide, TH350, or a 700R$/4L60 transmission isn't strong enough (torque rating) is too low. They can be made stronger with aftermarket parts but then the stronger transmission cost more than the TH400 or 4L80e to get the same gearing. Not economical to try and fight the design limits set by the engineers.

Big Dave
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post #4 of 11 (permalink) Old 07-12-2019, 08:11 PM
Join Date: Jul 2016
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Originally Posted by UMDSmith View Post
Here is a quick pic of the car prior to air ride. When I bought it, the previous owner had cut springs on it.
I like it! looks sinister and low, and I dig the steelies and dog bowl / copo type caps.

I concur with Dave. I would recommend a th400 or a 4l80e for a big block, but you *can* get away with using a th350, 4l60 or 700r4 for easy cruising. Some of it depends on your rear end and desired gearing as each of these vary with 3 or 4 speeds. Each of these transmissions also vary on their overdrive percentages. a 4l60 has a decent low first gear with decent torque, for example.

it really depends on the intended use. It also depends if you want pure hydraulics or if you want electronic control. I would go with a th400.

Free Trivia: most tv shows from the 70s and 80s with show cars that would come standard with a th350 were always switched to th400s because of the amount of abuse the transmissions could endure by the stuntmen performing 360s, reverse driving, jumps, etc.
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post #5 of 11 (permalink) Old 07-12-2019, 09:18 PM Thread Starter
Join Date: Jul 2019
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Have the transmission issue solved. I picked up a low mile gen IV 454 with a turbo 400 attached. I also have a modified 700r4 but that is going in my 1970 c20 since I'm stuck with 4:11 gears in the Eaton HO52 rear. The 454 is in pretty nice shape. I have it almost all the way torn down. I'm going to build it myself. Probably only going to add a top end kit, and just stick with the factory crank and pistons for now.

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post #6 of 11 (permalink) Old 07-13-2019, 09:56 AM
Join Date: Jan 2006
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You didn't say were you lived in your location question. But unless you live in California or one of the 12 states that still subscribe to emission testing (under threat of loosing federal money, or delusions of saving the planet) then those dished pistons (7.4:1) static compression) are going to hurt performance. If you keep them the good news is you can burn kerosene like in my 1948 John Deere tractor that has the same compression ratio from back when gas was rationed. Because today's gas isn't much better than kerosene you are limited to 9.8:1 static compression which you can get with a small dome pop up piston.

A big block loves compression, as it was designed for the road back when 104 octane was sold at the pump at SUNOCO and American gas stations. It likes ignition timing for the same reason. It has a poor head design left over from the early sixties concept of bigger is better in head port sizing. That low compression is a band aid in an attempt to cover the boo-boo of poor emissions. The factory did it to please California in an attempt to remove nitrates from the exhaust.

Big Dave
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post #7 of 11 (permalink) Old 07-15-2019, 01:05 PM Thread Starter
Join Date: Jul 2019
Posts: 10
Thanks Big Dave. I'm in Maryland, but being historic, and also the Eastern Shore, we don't have emissions. I actually run 91 octane ethanol free in all my carb'd applications (mowers, 70 c20, 67 bel air) because I can let it sit for a few months and not worry about it turning to crap.

I have gone back and forth in my head on what to do with this Bel Air. I got a good deal on the 454 and TH400, so I figured I'd run that, but then I was leaning toward 5.3 or 6.0 LS, then I was back on the 454, then a BluePrint 383 for ease of I am very much still at the planning phase. It really will come down to cost and time.

The 454 is the first engine tear down I have done, so I figured it would be a good thing to build and learn with. I wasn't going to tear into the bottom end, but given that crap compression, I may have to at least change out pistons. I was going to buy one of the top end kits for the 454. I wasn't shooting for crazy numbers, something like 450hp 500lb/ft would be more than enough for me, as that will easily destroy the rear end as it sits right now.
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post #8 of 11 (permalink) Old 07-15-2019, 01:51 PM
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What sets the BBC apart from the SBC and even the LS-x series is torque. The longer arm offered by a BBC offers more torque than any SBC (normaly aspirated). If you buy a a 496 rotating assembly for your 454 block and bolt on a set of '049 or '781 (or any of the similar castings with an open chamber and a large OVAL port instead of the small round "peanut port heads cast from 1976 and up), then you can easily meet your 450 horse goals. With a 496 you will more easily make your 500 foot pound goals in torque. You will make even more horsepower with a set of larger valve smaller combustion chamber aftermarket aluminum heads as they will breath even better than the factory cast iron heads. And at 496 you can even use a factory rectangular port head as you are at the 500 cube break even point for use of the larger port head.

Where the LS can easily make 500 horsepower; it will never make 500 foot pounds just off idle the way a longer stroke BBC will. If you were to limit yourself to 400 cubes with a 396 I would tel you to use a 400 cube SBC instead as it is more efficient (can make 500 horsepower were the 396 can not) and it weighs 220 pounds less than 396. Additionally a 400 would be cheaper to build than a 396 as it has cheaper parts.

Each engine offers advantages. A 5.3, 6.0 or a 6.2 liter LS coupled with a 6L90 transmission would be viable (offering similar performance) due to the added gears in the transmission. It would allow a smaller engine to multiply what torque it has the same way a semi tractor can pull a big heavy trailer on the road with a 20 or more gear changes per stop light. It would fall flat on it's face with a two speed Power Glide.

Big Dave
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post #9 of 11 (permalink) Old 07-15-2019, 04:22 PM
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Location: San Jose, CA
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Welcome. beautiful car.

PS no emission testing in California for vehicles made in 1975 or before.
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post #10 of 11 (permalink) Old 07-17-2019, 10:21 AM
Join Date: Aug 2008
Location: Miamisburg, Oh.
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That's sure a good lookin' ride! Nice. Big Block torque For-The-Win!

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post #11 of 11 (permalink) Old 07-17-2019, 04:32 PM Thread Starter
Join Date: Jul 2019
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Thanks all. I'll be posting progress pics. I have a few automotive projects before I get to this, such as swapping transmissions on my c20, and mostly restoring a 74 f100 for my stepdad. Then it is finishing this one up.
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