How fast will a C3 go?
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Joined: Aug 2006
Posts: 9
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From: Seattle WA
How fast will a C3 go?
I am trying to figure out how fast my old C3 might go. I have a '75 C3 with a built up 427 ci engine, Holley double-pumper, 3.08 posi rear-end and 700r4 tranny built to Bowtie Overdrive stage 3 specs. My brother is thinking about taking a couple cars next year to the Texas Mile and I wonder, with a little work and a roll cage, whether or not it is worth throwing the car on the transporter.
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
You need a chin spoiler on the front of your Vette like the 80-82 models or a bolt on like the 78-79's otherwise the front end will lift up and you probably won't want to get rolling more that 100mph. Properly set up and with enough power 180-190mph is possible who know maybe 200mph. 
There are some road racing guys on this forum that can give you a better idea, also gkull has allot of experience with this and can give you the info and setup and hp you need to reach your goals
There are some road racing guys on this forum that can give you a better idea, also gkull has allot of experience with this and can give you the info and setup and hp you need to reach your goals
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
You did NOT say what rpm of redline. But you would get a faster mph top speed with 3.73 or 3.90 rear gears
Last edited by gkull; Dec 19, 2008 at 12:57 PM.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Contrary to popular belief I can assure you a chrome bumper vette with NO spoiler/lower section in front can easily pass 150 mph and that is with the top and windows down....plenty of oompfgh left in the CAR, it's ME that can't do it....
with a 308 and a 700 and a 427, you have the gearing you should easy do 180, and 200 is more like it.....
I have proven the stock electronic tach is accurate in my car, and according to the www.secondstrike.com site, /technical/gearing calc.....
the engine with a 336 gearset and a 275/50/17 tire would be turning 5800 rpm at 200 mph.....damn close....so obviously for a 308 gearset knock 10% of that off....call it 5500 rpm, just loafing.....
Don't forget that your single largest issue is tires, you simply have to have a full Z rated tire, that means your 15" wheels are outta there, and 17+ rims are the ones.....better off with full NASCAR type rubber.....
I am convinced it really don't take 700 horses like NASCAR to do 200 mph, not in a shark anyway, they need it for pulling power over the next guy get TO that mark much faster, and so forth.....
Take a film clip, love to see it....U Tube....
with a 308 and a 700 and a 427, you have the gearing you should easy do 180, and 200 is more like it.....
I have proven the stock electronic tach is accurate in my car, and according to the www.secondstrike.com site, /technical/gearing calc.....
the engine with a 336 gearset and a 275/50/17 tire would be turning 5800 rpm at 200 mph.....damn close....so obviously for a 308 gearset knock 10% of that off....call it 5500 rpm, just loafing.....
Don't forget that your single largest issue is tires, you simply have to have a full Z rated tire, that means your 15" wheels are outta there, and 17+ rims are the ones.....better off with full NASCAR type rubber.....
I am convinced it really don't take 700 horses like NASCAR to do 200 mph, not in a shark anyway, they need it for pulling power over the next guy get TO that mark much faster, and so forth.....
Take a film clip, love to see it....U Tube....
Last edited by mrvette; Dec 19, 2008 at 04:27 AM.
Safety Car
Joined: Aug 2006
Posts: 4,102
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From: Forsyth Illinois
I read in Hot Rod mag some years back where a all aluminum BB 69 Camaro ran over 200 mph there,and was running on 7 cylinders.
The same guy owned a Fox bodied Stang that ran 177 I think it was.
My 75 L82 w/a mild rebuild,4 gear,and 3.55s out back has seen the 137 w/more left,and the 6x2 DZ in the 68 w/4 gear,and 3.55s in the assend has seen 146 w/alittle more on the table,but had a bald Goodyear Eagle w/belts showing,so thought the envelope was pushed fur enough...that day.
New haeds,and cam combo should be done at the machine shop today.
Pro
Joined: Dec 2006
Posts: 665
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From: wilmington nc
With 26 inch tires an a .67 overdrive your looking at 200 mph @5400 rpm. Here"s your calculator
http://www.wallaceracing.com/gear-speed.php
http://www.wallaceracing.com/gear-speed.php
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Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
Cmon guys. A C3 running 200 mph. You are going to need a good amount of HP and good aero. The C3 is not very sleek, as much as we think it is. The difference between running 140-150 and 200 is huge. You think the Nascar guys are spending millions to get that extra few mph and you are going to take a stock bodied C3 with some extra HP and run 200. I would love to see this done but it is going to take some heavy mods to do it.
Yea I have had mine at 140 with what seems like a lot left but to get another 50or so mph out of it, I seriously doubt it. I don't know how "built up" your 427 is but you have better be packing some serious HP to get to 200. Lokk at all the Bonneville racers and see what it takes to go 200.
Yea I have had mine at 140 with what seems like a lot left but to get another 50or so mph out of it, I seriously doubt it. I don't know how "built up" your 427 is but you have better be packing some serious HP to get to 200. Lokk at all the Bonneville racers and see what it takes to go 200.
Drifting
Joined: Jul 2006
Posts: 1,871
Likes: 6
From: Sault Ste. Marie Ontario
With 26 inch tires an a .67 overdrive your looking at 200 mph @5400 rpm. Here"s your calculator
http://www.wallaceracing.com/gear-speed.php
http://www.wallaceracing.com/gear-speed.php
Unfortunately at the moment, I would need a pretty fast tow vehicle to hit that mark
How fast can two guys push a car?
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
Cmon guys. A C3 running 200 mph. You are going to need a good amount of HP and good aero. The C3 is not very sleek, as much as we think it is. The difference between running 140-150 and 200 is huge. You think the Nascar guys are spending millions to get that extra few mph and you are going to take a stock bodied C3 with some extra HP and run 200. I would love to see this done but it is going to take some heavy mods to do it.
Yea I have had mine at 140 with what seems like a lot left but to get another 50or so mph out of it, I seriously doubt it. I don't know how "built up" your 427 is but you have better be packing some serious HP to get to 200. Lokk at all the Bonneville racers and see what it takes to go 200.
Yea I have had mine at 140 with what seems like a lot left but to get another 50or so mph out of it, I seriously doubt it. I don't know how "built up" your 427 is but you have better be packing some serious HP to get to 200. Lokk at all the Bonneville racers and see what it takes to go 200.
No greater truth has been spoken on this subject. If 200HP will get you 100mph ,400 will NOT get you 200mph.just doesnt work that way. co-efficienty,drag,wind AND road resistance,,gets alot greater/faster, the faster you go.
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
and it take maybe 120 hp to push a shark to 100 mph, and only 350 to run 200mph.....even the sharks with the super lo performance engines could easy to 120-140 so the above quote is way off in the calculations.....He got the concept of square law ok, but the initial numbers are way lo....
NOW, in saying the above, I did not say it would get there pulling like a F15 or something....but it's going to take way less than a mile.....maybe 1/2 mile at most....
Pro
Joined: Mar 2008
Posts: 716
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From: Albuquerque New Mexico
For what it's worth a trusty 'ol guy I know said he got his mostly stock '74 up to 145mph on a stretch of AZ hiway. He thought it had a tad more but that after going that fast for quite a while his side-pipes started to get that blue-ish finish from the pro-longed heat. I would think that with your big block and O.D. tranny combined with 3.08s you should be able to significantly top that. I would assume you also have sufficient tires designed to handle these type of speeds. Sounds like a fun adventure!!
Melting Slicks
Joined: Jan 2003
Posts: 2,877
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From: Doha
St. Jude Donor '08
I remember I read somewhere that the '68/'69 L88s were known to be able to hit 200 MPH with stock everything! .. and I do know that its relatively easy to upgrade any C3 to a L88 rated suspension, which is the only difference between the L88s and rest of C3s of the same era.
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
I remember I read somewhere that the '68/'69 L88s were known to be able to hit 200 MPH with stock everything! .. and I do know that its relatively easy to upgrade any C3 to a L88 rated suspension, which is the only difference between the L88s and rest of C3s of the same era.
Most of those guys running the open road races that are up in the 180 mph range have gobs of HP and body mods to keep it stable.
