hello, i have just purchased a 1981 corvette,i noticed that the 81 vette only has 190 HP, but has a 350 engine with 280 lbs of torque. why is this? and what are some easy ways i can make my vette have more HP. Also any easy upgrades that can be done, Thank you.

 

Cam, headers, high-flowing cat.

 

Do this.....
Remove entire computer system.....Cat....Tail Pipes and Mufflers
Remove Engine....Replace with Bill Mitchell 415 ci Small Block Crate Engine.
Remove Trans....Replace with HP police 700R4 with special racing clutches
and shift kit.
Remove Stall Converter.....Replace with Super Yank 3500.
Remove all U-Joints.....Replace with Spicer Zerless Joints.
Remove Rear end....Replace with 3:70 Gears.
Remove all Stock Suspension System....Replace with VetteBrakes System.
Install Smart Struts....Bilstein Sport Shocks....
Install MT ET Streets.....Go to track and run 11's....Be Happy....Then
Go home and stay there untill you can find a friend to install 8 point roll cage....5 point safety Harness....shaft loops....
There are no cheap or easy ways to perfomance.....or you'll waste your money like I did.....go right to the good stuff first....so later you won't have all the cheap stuff to replace and get rid of when you buy the good stuff..... :D

 

The stock exhaust is pretty restrictive on a stock '81. I'm pretty sure you can make some decent power out of the stock computer carb/intake setup with some new heads, a cam, and a dual exhaust.

 

:iagree: See my sig. That's respectable power without going crazy on mods, and running all stock computer, carb, and distributor systems. :yesnod:


-Justin

 

Here is my 81 4spd, it didn,t cost an outragous amount of money and it goes ok. The only mistake I made was putting to much cam in and have since changed it for a more torquey Comp Cam. With the original Edelbrock RPM cam the clutch lasted less than 500 miles, it needed to much to get it going and the first time I took it to the track the clutch was completely destroyed. The new one is probably overkill but it isn,t going to slip. Have a look on my site for some better pictures and a couple of short mpegs.

J.


[Modified by JHL81, 6:52 AM 8/9/2003]


[Modified by JHL81, 5:08 PM 8/9/2003]

 

I have domed pistons (10:1 compression), crane 2030 cam and a freeflow cat. This has made a big difference. I haven't had it on a dyno, but I had to have added atleast 50hp. A custom exhaust will proabably be done after I get it repainted.

 

so far, all good suggestions. the question that we need to provide you with more specific information is what are your specific goals? do you want 600hp, regardless of street legal or smog? just as much as you can get without tearing into the engine? are you looking for a particular HP number or drag ET?
to answer your first questions, the car had a very low horsepower rating primarily because of the restrictions required to meet smog and fuel economy standards. the torque number vs. the HP number is an indicator the exhaust was a major restriction in the system. torque numbers tend to fall off as RPMs increase while HP increases...typically. the problem is/was that the exhaust, more specifically, the early 'pellet-type' catalytic converters were extremely restrictive. they flowed reasonably well at low RPM (hence, good torque) but severly impacted the evacuation of exhaust gases with increasing revolutions.
very important to note that, it's your first key to making more power. if your not so restricted by smog laws, replace the single cat with two high flow cats or even 'test tubes' (open pipe) to reduce the restriction. that will free up ~10hp by itself. if you can, junk and replace the entire exhaust system. the nasty pipes, headers and cat that came on the system from the factory is just gawdawful.
i'm not a computer hater so i never recommend tossing the computer, they have some reliability issues but when they work, they work just fine. they don't significantly hinder your ability to modify either. you can't generally use a solid lift or roller cam with the early computer engines due to internal noise interfering with the knock sensor readings, but any of the more streetable hydraulic cams will work just fine.
the q-jet flows bunches of air so tossing it in favor of a holley isn't what i would consider to be money well spent. just make sure it's in good tune and you'll be fine. you might want to add a nice ignition system to the factory distributor but otherwise, that system is fine too and required to work with the carb/computer system.
aside from that, it's just another SBC and the same rules pretty much apply i.e. 'no replacement for displacement', more compression, more cam. all will help--in moderation.