Deleted due to all the hate in DMs.

 

Rear tire diameter ?

 

Deleted

 

A different engine might have a better chance at making the speed goals you have. Why did you choose to use a L98 engine block for the build?

The L98 is a nice engine but 200 mph? My 1988 C4 has the L98 in it and it is an okay engine, certainly not a power house of an engine. My other Corvette is a C3 with its 427 BB built to be a L88 Clone. The torque that beast makes pulls the car to high speeds very easily. I would imagine the aerodynamics of a C4 "might" be able to to break into the 200 mph club but it will take a ton of money to make the power needed to get that fast.

If you started with a BB engine then your run might end north of 200 mph a bit less expensively. With the compression and engine build the 427 can go pretty quickly and "pass easily" at over 100 mph so going a bit more should be an easier target. I have a 3.36 rear and a Muncie 4 speed with my 560+ hp and it can run!

Knowing how bad the 1968 C3 wants to lift the front end at 115-120 mph I could not imagine it at 200 mph without some serious modifications and extra weight.

Have you calculated just how much power you will need to go 200 mph in a C4 Corvette? Twin Turbo's, Supercharger? Both? You will need a bit more carburetor to get the engine to the speeds needed. You might want to stick with the lower gear rear axle versus the 3.42-1 you are thinking about. To go that fast you need a lot of power and a low rear ratio to get the tire speeds you will need.

What car are you planning to do it in?

 

Deleted

 

That cam is capable of max HP around 6500rpm

The 2 intake manifolds you have are designed for operation and max HP below 5500rpm.

The 650cfm carb you have is likely borderline too small.

With the amount of money and effort you have invested in the rest of this build, I would suggest buying an Edelbrock Performer RPM or Victor Junior intake manifold. The Vic Junior might make a little more top end power but sacrifice some mid range. The Vic Junior is capable of legit 7000+RPM power...with the right cam. The cam you have will probably sign off around there.

A 750cfm 4150 style double pumper will feed that combination. Holley, Quick Fuel, Brawler, Demon. Any of those would suffice.

 

Totally not Corvette related, but when I was a punk kid with my 87 V6 Fiero... I remember having the pedal FLOORED... I had the needle pegged past the 120mph mark... I was probably doing 125-130 tops. I still had about 500-600 rpms left on the tachometer before it got into the yellow / redline area... but the car just wouldn't go any faster. No matter how hard I tried to push the pedal down further... it just sat at that same speed... haha...

I guess that's the point at which the friction in the road, and the coefficient of drag overcomes the 140 horsepower and 2700 pound chassis weight.

 

That engine isn't making 600 horsepower. With that cam/carb/intake setup, I'd be surprised if it makes 500 horsepower.

 

Agreed. Maybe a 450-460hp motor the way it sits, and I am being generous IMO.

 

500 is possible.
needs 1.65 rockers.= 600 lift
plus that will add 2 degree duration at .050 on intake and exhaust ,same advertised duration.
Heads must flow well to 600 lift . Idk about that. And min csa needs to be correct for the rpm . Better valve springs as well.

Victor jr opened up is mandatory
then 500 is possible.
full length header/ good duel exhaust mandatory .

 

Guy deleted all of his posts because he didn't like being told his 450 horsepower engine didn't make the claimed 600 horsepower.

 

I wonder what kind of hate he got in PMs?

I've noticed (and I'll get a lot of flack for this) on my short time here... that a large number of Corvette owners don't really know their cars. There are definitely a lot of smart people here... but many aren't really car people... but that's not a bad thing, what I mean is... they have no intention of fixing their car when people give them advice. I've seen a bunch of messages here where someone says, "something's wrong," and then unfortunately, after people respond, they're not mechanically inclined enough to actually do anything about it when people provide advice to them on how to fix it.

Not knocking people, but the only other place I saw that was on the Porsche forums when I used to have a Porsche. I suppose that's both a positive and a negative... the Corvette is a desirable car, but it seems like it also attracts people who, like this, have lofty and often unrealistic ideas. I suspect that's why there's also a lot of C4s that have low mileage and are inexpensive. Doctors, research scientists, lots of non-car people bought them and drove them until it became a problem.

When you start going on the more plebeian sites, haha... all the ones I'm normally on. You get real shade tree mechanics, hahah... here's how you fix a leaking EGR tube... take duct tape, wrap it around 10 times, and then heat the car up good so it becomes a melted plastic seal!