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Is an L48 worth adding performance?

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Old Dec 22, 2017 | 03:04 PM
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C6 and C7 Corvette Z06's do 11's or less (10.9 C7Z06) in the 1/4 mile....A C3 would need at least 600 Gross HP (not Net like the newer cars are rated) to keep up and/or beat. How much HP and traction do you think a C3 needs to do 3.2-3.6secs 0-60 MPH?
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Old Dec 22, 2017 | 03:07 PM
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How many z06 Corvettes do you see? How many are driven by people that can make them run that good?
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Old Dec 22, 2017 | 03:15 PM
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Originally Posted by 7t9l82
How many z06 Corvettes do you see? How many are driven by people that can make them run that good?
Actually I go to Gillette Stadium with my 10 C6Z06 for their car show every 2 weeks during April-Oct and see about 15-20 C6/C7 Z06's every time. The Automatic C7Z06's can punch out low 11's easily as well as 3 sec 0-60 MPH consistently. Regardless, a C3 needs mucho Gross HP to post numbers like that either way like I said originally......
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Old Dec 22, 2017 | 03:34 PM
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I wasn't referring to a club or group that shows up at a drag strip, and I wasn't talking about a car that could beat everything on the street. I was however talking about a car that could take on and beat a fair number of modern cars. The fact is alot of these new cars are driven buy people that just can't turn a number. Most of these clowns can't shift worth a darn and have no ability .
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Old Dec 22, 2017 | 06:13 PM
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WOW. 5 pages and we lost the OP at post 26. To answer his question as best as I can. You mentioned selling the car and if that is your plan then no, you will never get your money back from motor upgrades. If you want to use it as a fun little cruise car for a while then a cam intake and some old school head work will make it a fun ride. Add some coated headers and chambered exhaust and it will sound awesome.
You don't need 400+ ponies to have fun in a classic car. In fact, most C3's on the road today would be unsafe with that kind of power without extensive chassis and brake rebuilds. Going fast is a lot of fun but not stopping in time will spoil your day.
Jerry
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Old Dec 23, 2017 | 09:17 AM
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Originally Posted by shenango
WOW. 5 pages and we lost the OP at post 26. To answer his question as best as I can. You mentioned selling the car and if that is your plan then no, you will never get your money back from motor upgrades. If you want to use it as a fun little cruise car for a while then a cam intake and some old school head work will make it a fun ride. Add some coated headers and chambered exhaust and it will sound awesome.
You don't need 400+ ponies to have fun in a classic car. In fact, most C3's on the road today would be unsafe with that kind of power without extensive chassis and brake rebuilds. Going fast is a lot of fun but not stopping in time will spoil your day.
Jerry
I agree completely that a classic C3 probably on the street does not need 400+ Gross HP to be fun and without major mods could be unsafe on the street with that type of power.

When I was rebuilding/upgrading my OEM L-82 355 4 speed 3.70 gears, I specifically targeted a reasonable strong gross HP figure with good bottom end and most importantly, tremendous mid range torque from 2,000-4,500 rpm. Even with a completely rebuilt/upgraded suspension, custom blueprinted/rebuilt OEM steering box, OEM stock brakes with Upgraded carbon/metallic pads with the 4 piston calipers, and ultra High performance 17 rims with 255/45/17 ZR rated rubber AND STILLL with my 425+ Gross HP, the engine's potential cannot be reached on the street...great for road course racing, but somewhat marginal when you wind the motor out to 6,000 RPM on the street.

There is Zero compatibility versus my 10C6Z06 in terms of safety margin with high HP since the Z traction, steering, handling, braking and stability are FAR superior to the C3.....
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Old Dec 25, 2017 | 08:36 AM
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the first 30 years, 53 to 82,all they did was put in a half-assed IRS and better brakes after the first 10 years. other than that there was almost no engineering done to suspension and handling. it was and is a beautiful car with a fair bit of motor. come 84 they actually started doing real work on suspension and brakes... and they apparently never stopped. the handling and stopping today is way more than 30 years more advanced than it was back when these beasties were being built.
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Old Dec 25, 2017 | 09:10 AM
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Originally Posted by derekderek
the first 30 years, 53 to 82,all they did was put in a half-assed IRS and better brakes after the first 10 years. other than that there was almost no engineering done to suspension and handling. it was and is a beautiful car with a fair bit of motor. come 84 they actually started doing real work on suspension and brakes... and they apparently never stopped. the handling and stopping today is way more than 30 years more advanced than it was back when these beasties were being built.
The C4 suspension and steering were far superior to the C3's but the brakes on the other hand for the C4's were actually a step backwards and inferior in basic design to the C3's. The 4 single piston calipers (aluminum would be the only advantage) with 11.5 inch discs, smaller brake pads than the C3's, and with a smaller caliper that would flex a ton under severe braking. The real brake advantage of the early C4's was the superior tires. GM upgraded the brakes to the "big" brake package to address the shortcomings in 1988 with 13 inch front rotors and dual piston front calipers...The quantum leap forward in Corvette brakes came with the C6Z06 with 14 inch rotors/front 6 piston calipers and 13 inch rear rotors and back to the c3 basic caliper design of 4 pistons at each rear wheel.

The C3 basic design was Years ahead of it time and when working correctly are terrific brakes even today on the street.

Up to the VERY recent few years, it was very rare to get a fixed multi piston Front AND rear calipers on sports cars with oversized rotors..

Last edited by jb78L-82; Dec 25, 2017 at 09:46 AM.
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Old Dec 25, 2017 | 09:19 AM
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Originally Posted by derekderek
the first 30 years, 53 to 82,all they did was put in a half-assed IRS and better brakes after the first 10 years. other than that there was almost no engineering done to suspension and handling. it was and is a beautiful car with a fair bit of motor. come 84 they actually started doing real work on suspension and brakes... and they apparently never stopped. the handling and stopping today is way more than 30 years more advanced than it was back when these beasties were being built.
There is a large difference between a L-48 and a L-82 . I have owned two L-48 which had no power and one was barely broken in. Now the L-82 stock 77,000 miles with a four speed and never rebuilt is like a rocket ship compared to the L-48 . I would rather drive my L-82 than my 300 hp. 93 vette . There is so much character to the C3 and people always rave at its looks. Also you can repair the C3 easily were the later cars are all computer controlled and a pain to work on. Happy New Year!
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Old Dec 25, 2017 | 01:37 PM
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Originally Posted by fake
There is a large difference between a L-48 and a L-82 . I have owned two L-48 which had no power and one was barely broken in. Now the L-82 stock 77,000 miles with a four speed and never rebuilt is like a rocket ship compared to the L-48 . I would rather drive my L-82 than my 300 hp. 93 vette . There is so much character to the C3 and people always rave at its looks. Also you can repair the C3 easily were the later cars are all computer controlled and a pain to work on. Happy New Year!
You are absolutely correct...there was and is a BIG difference between stock L-48 and L-82's back then and today.

The issue boils down to a few points of view:

1. There are some who either owned or own base/passenger car L-48 C3's and don't want to admit that the 2 cars are not the same...in fact there is a big difference if the cars are stock or near stock. Any bolt on mods or emission deletions will help both an L-48 or L-82 but the L-82 will always respond better to mods because of the superior baseline architecture. And you are correct, I personally have driven brand new L-48/L-82's, autos/4 speeds both when new and even today, and the stockish L-48 is an absolute dog compared to a stockish L-82 today and back in the late 70's..zero comparison....and please don't chime in that I had such and such an L-48 that smoked an L-82....not possible in a equal race with stock engines. The documented numbers at the time support everything said here and by others.

2. The L-48 2 bolt main block, cast crankshaft, L-48 rods can support a 400 Gross HP upgrade. The L-82 4 bolt main, forged rods, forged crankshaft, can support MUCH more HP and do it with much of the stock components.

3. If you scrap everything in both blocks for a stroker crank, the L-82 will be still be the better base block it is a 4 bolt main

The L48 is a GM passenger car engine and The L-82/LT-1's were not......

Last edited by jb78L-82; Dec 25, 2017 at 02:12 PM.
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Old Dec 25, 2017 | 02:24 PM
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And if you do gut an L82 to do the 383 thing, please send me the crank and rods...
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Old Dec 25, 2017 | 02:33 PM
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Originally Posted by derekderek
And if you do gut an L82 to do the 383 thing, please send me the crank and rods...
My L-82 355 has the OEM forged Crank, OEM Forged L-82 rods, numbers matching 4 bolt block, L-82 OEM aluminum intake, L-82 cold air intake system AND makes 450 Gross HP....a 383 conversion was never even a consideration for me and sure glad I kept it an L-82 bored....Let's put it this way, I have zero fear of the power of just about any 383......
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Old Dec 27, 2017 | 03:05 PM
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Originally Posted by jb78L-82
..Let's put it this way, I have zero fear of the power of just about any 383......
Let me know if you bring your C3 to Jersey some time.
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Old Dec 27, 2017 | 04:27 PM
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Originally Posted by BKbroiler
Let me know if you bring your C3 to Jersey some time.

Not ever single 383!...obviously, a 383 built to the max 500-550+ Gross HP is going to win every day....most are not.....more like 425-450 Gross HP range.....

Last edited by jb78L-82; Dec 27, 2017 at 04:29 PM.
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Old Dec 27, 2017 | 04:49 PM
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Originally Posted by jb78L-82
Not ever single 383!...obviously, a 383 built to the max 500-550+ Gross HP is going to win every day....most are not.....more like 425-450 Gross HP range.....
Just poking a little fun. But, performance is really in the combination of parts in the car. Dyno numbers don't tell the whole story. I have no dyno experience, but plenty of 1/4 mile data. Using published weight to trap speed charts (3,640 lbs incl me, 110 mph) yields 400 hp, at most. I assume thats net, flywheel hp. I've made a number of runs in the 12.15 to 12.20 range. My point is, my 400 hp 383 is fairly mild, but in my car, in a heads-up race, it will outrun many much more powerful cars.
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Old Dec 27, 2017 | 05:06 PM
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Originally Posted by BKbroiler
Just poking a little fun. But, performance is really in the combination of parts in the car. Dyno numbers don't tell the whole story. I have no dyno experience, but plenty of 1/4 mile data. Using published weight to trap speed charts (3,640 lbs incl me, 110 mph) yields 400 hp, at most. I assume thats net, flywheel hp. I've made a number of runs in the 12.15 to 12.20 range. My point is, my 400 hp 383 is fairly mild, but in my car, in a heads-up race, it will outrun many much more powerful cars.
Wow..those are pretty impressive 1/4 miles numbers...I would assume 12.1-12.2 times would be 390-400 RWHP HP, not Gross/net....That's impressive.....
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Old Dec 27, 2017 | 05:44 PM
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Originally Posted by jb78L-82
Wow..those are pretty impressive 1/4 miles numbers...I would assume 12.1-12.2 times would be 390-400 RWHP HP, not Gross/net....That's impressive.....
Thanks
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Old Dec 27, 2017 | 10:20 PM
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Originally Posted by BKbroiler
Thanks
Using 3640 lbs and 110 mph and the calculator on the Drag Times .com it says 378 rwhp . Very good numbers .
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Old Dec 28, 2017 | 10:53 AM
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Originally Posted by gveld
Using 3640 lbs and 110 mph and the calculator on the Drag Times .com it says 378 rwhp . Very good numbers .

Thanks. I'm happy with that number. The numbers vary depending on which calculator you use. Kind of like dyno results.
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