ray7459

I have about $2400 and I would like some advice on how I can best use it to increase the horsepower in my 1981 corvette. It's pretty much all stock except I have the exuast dulled out with 3 1/2" pipe and a flowmaster.

Durango_Boy

How's the bottom end? Do a compression test and see if your bottom end is in need of rebuilding.

Then...

Vortec heads.
Vortec manifold.
Stock carb W/ tune.
New timing set.
Cam and lifter combo.
Time the engine.
Perform tuneup and fluid change.

That'll get you close to 9.5:1 and with the exhaust you already have, around 100 more HP.

You can save money by buying used Vortec heads, but you'll still need to have a little machine work done. You can also buy some Vortec heads from an after market company that are ready to bolt on.

With the Vortec heads, you will also need either self aligning rockers or guide plates and hardened push rods.

There are a few extra details, but that's a great way to get some extra HP.

SIXFOOTER

The keys to making an 81 strong is breathing. You already have the exhaust done which is a must for any HP mods. I assume you have some kind of headers, 3" pipe and flowmaster mufflers? What about the cat?
You will need at a minimum Heads and a better cam
do the job in stages, learn as you go and see what works as you drive it some between stages
do the heads and cam in one go, the intake should be an aluminum Edlebrock 2101 which is a good unit. Get the carb gone thru by a COMPETENT carb expert, If you have trouble finding one Me or one of the other 81 owners can help. Don't let some moron try and sell you a new carb, distributor etc without at least trying to get yours fixed up first.
There are several head choices: Used Vortec is a good one but requires changing the intake too. There is Iron Eagle, AFR ($$ but worth it).
There are several cams out there that would be appropriate for under 200 with lifters.

This will put quite a bit of power in your hands, approaching 300 hp.

Next I would change the 3 speed TH350 Auto tranny out for a TH2004R, it has a better gearset and overdrive, it is a near bolt in modification and can be built for serious power under $900 total.

Then there is the rear end, a simple gear change or change out the differential for an Iron unit from an earlier year, it is Much Stronger.

you should be able to do the heads, cam and tranny for under the $2400 budget.

NHRalph

First thing to do is check out the engine as it is,do a compression and a leak-down test. Then you need to determine just how much more power you want. Getting 300 horses at the crank, out of it is easy, a good intake manifold, good carb and headers, true duals and some head work and cam and your there.
Write up a plan on what you want, then you can do it as fast or as slow as you want and for a lot less then 2400.

Bill Lattrell

NHRalph, I agree with you. The only problem is the Hood Clearance with a good Intake manifold and,Carb. Edelbrock Performer Manifold (non EGR) #2101 won't work with hood clearance. With a EdelbrockCFM Manual Choke #1405,,,,,not happening have to purchase a induction hood.

cv67

Drop base wont fit? What about a carb hat with round tubing theres always a way. Anything but leaving an 81 stock!

Metalhead140

No need for a taller hood? I have a performer rpm intake (0.7" taller than the #2101) under my stock '79 hood with a drop base and 3" tall filter.

Ibanez540r

The OP's last activity was in 2009... not so sure he needs anymore help.