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Discussion Starter #1
Looking for a torque graph of a stock C code or A code engine. Mine's a stock C code and it's getting an autolite 4100 soon. Just looking for something to plan my rear gears for.

I did this in Excel this morning, still not sure if I want to go with the 3.25 or the 3.55. It's clear that once the T-5 is in, the 2.79s gotta go.

The vertical bold lines show what I consider a "reasonable" shift range between 1500-3500rpm. I assumed the engine redlines at 7,000 rpms and deleted all data above that.

The green entry is for final cruising at 70mph

Thanks
-Matt
 

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I dont think a factory C code with a 4V carb is the same as a factory A code.
I think the higher compression of the A code would give you a different torque curve than a C code with the 4 bbl carb.
Didnt the C codes have dished pistons and the A codes flat-tops?

Joe
 

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Discussion Starter #3
I dont think a factory C code with a 4V carb is the same as a factory A code.
I think the higher compression of the A code would give you a different torque curve than a C code with the 4 bbl carb.
Didnt the C codes have dished pistons and the A codes flat-tops?

Joe
Yeah. But I doubt that I'll be able to find a torque curve of my exact setup. But I can look at an A code curve or a C code curve and make an educated guess. That's one thing they hammer into us here at school, "Engineering Judgement"
 

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Ahhh an engineer...I should have suspected so. What with the Excel sheets and the questions about "reasonable shift ranges".

Tell ya what kid...put the 3.50s in it and shift up (without lifting your right foot) when you hear a loud clacking sound...thats your stock valve-train protesting your crude methods.

By the way:
Five surgeons were taking a coffee break and were discussing their work. The first said, "I think accountants are the easiest to operate on. You open them up and everything inside is numbered."
The second said, "I think librarians are the easiest to operate on. You open them up and everything inside is in alphabetical order."
The third said, "I like to operate on electricians. You open them up and everything inside is color-coded."
The fourth one said, "I like to operate on lawyers. They're heartless, spineless, gutless, and their heads and their butts are interchangeable."
Fifth surgeon said, "I like Engineers...they always understand when you have a few parts left over at the end..."


Hahaha...I joke I joke. Just trying to make you smile :)

Good luck with your project and your education.

Joe
 

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Discussion Starter #5
By the way:
Five surgeons were taking a coffee break and were discussing their work. The first said, "I think accountants are the easiest to operate on. You open them up and everything inside is numbered."
The second said, "I think librarians are the easiest to operate on. You open them up and everything inside is in alphabetical order."
The third said, "I like to operate on electricians. You open them up and everything inside is color-coded."
The fourth one said, "I like to operate on lawyers. They're heartless, spineless, gutless, and their heads and their butts are interchangeable."
Fifth surgeon said, "I like Engineers...they always understand when you have a few parts left over at the end..."
Hahahaha! I find myself with left over parts all the time. Usually I look at something and think "What the hell does that thing do? I don't need it."
 

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Looking for a torque graph of a stock C code or A code engine. Mine's a stock C code and it's getting an autolite 4100 soon. Just looking for something to plan my rear gears for.

I did this in Excel this morning, still not sure if I want to go with the 3.25 or the 3.55. It's clear that once the T-5 is in, the 2.79s gotta go.

The vertical bold lines show what I consider a "reasonable" shift range between 1500-3500rpm. I assumed the engine redlines at 7,000 rpms and deleted all data above that.

The green entry is for final cruising at 70mph

Thanks
-Matt
I think you'll be lucky to make 6200 without float. The operative word, being "lucky".
But, have fun anyway and let us know how boxes you needed to collect the parts. LOL
Happy Motoring!
 

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They'll tend to float at 5400. Or you'll get point bounce in your dizzy, and THAT will keep it from revving higher.
 

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Discussion Starter #8
They'll tend to float at 5400. Or you'll get point bounce in your dizzy, and THAT will keep it from revving higher.
Wellll, I can replace the ignition. That's easy.
 

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having had several A codes back in the 70's below the 100,000 mile mark i will say you will be doing good to get 5000 rpm with a stock one cause that cam just aint big enough to go higher. the C code came with dished pistons and the A code had flat tops and both had 4 valve releifs.
 

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+1 on that.
5000 is about what you see with a factory A-code cam & valvetrain.
 

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+1 on that.
5000 is about what you see with a factory A-code cam & valvetrain.
I had C and A-codes back in the day. They would rev to 5000 before valve float but it was a waste of time. They were all out of breath about 4500 (maybe because of worn valve springs).
 

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Discussion Starter #12
You guys just keep lowering that RPM band. It steps down every time there's a new reply...
 

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We're not lowering the rpm band. That's inherent with the valve train design. 5000-5200 for valve float is pretty close. The K code and Boss 302 had solid lifters and were designed for around 6000 rpm at peak horsepower.
 

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I had a stock C code with a Holley 4 barrel on it back in the 80's when I was in high school. I put 3.40's in the rear, and I think its pretty safe to say these guys are exactly right. I ran it as hard as I could, but at about 5,500 it was all over.

You'll like the T-5, but 3.55's are definitely the max you'll want if its got the 3.35 first in the trans. You'll run out of gear and your engine will run out of breath real quick if its stock.

If your on a limited budget, try it with the 2.79's. A 3.35 first in the trans (if thats the T-5 you have) will really make a difference.
 

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+1 with "Slim". I'll admit, my comment of 6200 Rs was very generous and based on old days of racing against the the BP mustangs. But, as noted, was the solid lifter GT 350s.
Obviously, the reason it came down was through direct and probably hands-on experience by the guys making their comments. But valve float can be good as it is a good "built-in rev-limiter" to save your engine.
I have a well thought out and purposeful built engine and it's red-line is a reliable 7000 with peak shifting at 6500. This is only 1500 above a 45 year old factory built engine.
Happy Motoring!
 

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Hey,

I looked at your spreadsheet and it looks like you've got the 2.95 first, which is probably a nicer trans. I think you'll be happy with either gear with a 3.25 or a 3.55, it really depends on you future plans. If you want a lot more cam in the future go 3.55's.
 

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+1 Much agreed! I have it all. T5z+nice cam+3.55. 16 mpg Plus get out of the way I'm coming through!
Ken
 

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Even though the motor quit pulling at 4500 my brother put in a 4.11 gear with a wide ratio 4-speed. Got off the line very quickly and with a Hurst shifter he got to 60 mph in a hurry. Surprised a lot of big blocks.
 
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