gowhitten

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.

MotorHead

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

theandies

I know for a fact that mine will go 137mph and still had a little more.

gkull

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

mrvette

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....

vettesbydesign

gkull.....have you ever ran the vette,or whatever on the Silver Crown Classic there in Nevada?I have yet to make it,but have always dreamed of running it.I will.....
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.

vettesbydesign

To the OP.......take the car.Of course,we all wanna finish up front,but take the car,and represent us all!!!!

dmaaero

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

Yeller81USNRet

My 81 will go 85 MPH says so on the Speedometer.
Ken

Gordonm

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.

eastltd

According to the calculation my set-up would net 143.44MPH at the 6K rev limiter.

Unfortunately at the moment, I would need a pretty fast tow vehicle to hit that mark

How fast can two guys push a car?

ghoastrider1

ghoastrider1

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.

mrvette

The question is, really how much actual HP does it take to get 200 out of the 3 basic body styles of shark??? 68-72, 73-77, and 78-82??? I willing to bet the 68-72 takes less than the others....

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....

WillEE

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!!

HamadUP

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.

Gordonm

No way were these cars stock. These were fully race prepped C3 L88 cars that ran at Lemans. They rarely hit 200 and most of the time the drivers said the front end was lifting at 170 or above and the steering was real dicey at that speed. It will take way more than 500 HP to push a stock bodied C3 to 200 mph. I don't care if you have 10 miles. Go look at some Bonneville racers and see what they are pushing for bodies and HP. Again I say the difference between 130 and 200 is ten fold if not more.

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.

Guru_4_hire

My spedometer stops at 160.

Ron R

It comes in handy when you get pulled over. "Do you know how fast you were going?" "Yes sir, 85 Mph."

jnb5101

are you guys nuts?