81 Corvette Engine Build
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Joined: Nov 2011
Posts: 64
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From: Medford OK
81 Corvette Engine Build
Hey guys i've got an 1981 Vette thats pretty much stock so far in everything but the exhaust which has been upgraded to the standard Magnaflow headers, pipes, and mufflers. Im looking to pull around 350-400 hp out of it. What would I need to do to get this kind of power and what would it cost me approximately.
Heel & Toe
Joined: Sep 2011
Posts: 18
Likes: 0
From: Amarillo Texas
Go with the top end kit for now.
My uncles 81 with an edelbrock intake, holley 650, headers and flowmasters put down an "astounding" 170 hp.. To achieve 350-400 you should go with heads/cam and a bigger carb setup and see how that does.
Your looking at spending AT LEAST a couple grand for a good top end kit. I know edelbrocks runs around $2k a little lower or higher depending on setup. But with all cars you cant just focus on the engine, after you get close to that 350-400 it would be a good idea to get a stall and shift kit, then all the way out back switch to some lower gears. My uncle just spent around 8 grand on a 400 engine and hughes performance transmission. I spent $5k on my 383 stroker. Horsepower is gonna cost you money, it just depends on how much your willing to dish out..
My uncles 81 with an edelbrock intake, holley 650, headers and flowmasters put down an "astounding" 170 hp.. To achieve 350-400 you should go with heads/cam and a bigger carb setup and see how that does.
Your looking at spending AT LEAST a couple grand for a good top end kit. I know edelbrocks runs around $2k a little lower or higher depending on setup. But with all cars you cant just focus on the engine, after you get close to that 350-400 it would be a good idea to get a stall and shift kit, then all the way out back switch to some lower gears. My uncle just spent around 8 grand on a 400 engine and hughes performance transmission. I spent $5k on my 383 stroker. Horsepower is gonna cost you money, it just depends on how much your willing to dish out..
Thread Starter
Advanced
Joined: Nov 2011
Posts: 64
Likes: 0
From: Medford OK
Go with the top end kit for now.
My uncles 81 with an edelbrock intake, holley 650, headers and flowmasters put down an "astounding" 170 hp.. To achieve 350-400 you should go with heads/cam and a bigger carb setup and see how that does.
Your looking at spending AT LEAST a couple grand for a good top end kit. I know edelbrocks runs around $2k a little lower or higher depending on setup. But with all cars you cant just focus on the engine, after you get close to that 350-400 it would be a good idea to get a stall and shift kit, then all the way out back switch to some lower gears. My uncle just spent around 8 grand on a 400 engine and hughes performance transmission. I spent $5k on my 383 stroker. Horsepower is gonna cost you money, it just depends on how much your willing to dish out..
My uncles 81 with an edelbrock intake, holley 650, headers and flowmasters put down an "astounding" 170 hp.. To achieve 350-400 you should go with heads/cam and a bigger carb setup and see how that does.
Your looking at spending AT LEAST a couple grand for a good top end kit. I know edelbrocks runs around $2k a little lower or higher depending on setup. But with all cars you cant just focus on the engine, after you get close to that 350-400 it would be a good idea to get a stall and shift kit, then all the way out back switch to some lower gears. My uncle just spent around 8 grand on a 400 engine and hughes performance transmission. I spent $5k on my 383 stroker. Horsepower is gonna cost you money, it just depends on how much your willing to dish out..
Heel & Toe
Joined: Sep 2011
Posts: 18
Likes: 0
From: Amarillo Texas
That setup should have you easily around 400hp depending on cam and heads of course. Depending on how good your block is now depends on if its easier to go with a fresh block or keep yours. You never know what your gonna run into until you pull it out. I had to get a new block for mine and start from scratch. Do plan to get it bored .030 over if 383 is your plan. You'd be good on the exhaust side since you've got a good pair of headers. You'll also be looking at going ahead and upgrading your distributor with the added horsepower as well as your wires. You can easily get into a few grand for all this. But I couldn't be happier with my 383
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Joined: Nov 2011
Posts: 64
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From: Medford OK
The block is the original with 59,000 easy miles on it. It doesn't use hardly any oil. The plug wires were also replaced when the headers were installed and high performance wires and plug ends were installed. The only issue i've ever really had with the car is that right now the alignment on the rear wheels is off. Instead of being around 0 degrees they are very obvious to the eye off in that one could eyeball them at around 3-5 degrees off. That sure makes for an interesting driving experience haha. Would I additionally need to upgrade the fuel pump to account for obvious increased need for pressure when the 800 opens up?
Heel & Toe
Joined: Sep 2011
Posts: 18
Likes: 0
From: Amarillo Texas
http://www.summitracing.com/parts/EDL-1721/
This is the pump I use but I know of others who stay with the stock pump and it run just fine.. I've heard that the stock ones are capable of handling up to 375hp but not sure how true that statement is. The only reason I went ahead and replaced it was to be on the safe side.. I'd say you have a hell of block if its at 59k! With that you should be able to stick with your block and save some $$ which is always good. I know my uncles 81 gears sat at 2.92 if Im correct? With 400hp you should look into lower gears while your at it if you wanna be able to handle the power.
This is the pump I use but I know of others who stay with the stock pump and it run just fine.. I've heard that the stock ones are capable of handling up to 375hp but not sure how true that statement is. The only reason I went ahead and replaced it was to be on the safe side.. I'd say you have a hell of block if its at 59k! With that you should be able to stick with your block and save some $$ which is always good. I know my uncles 81 gears sat at 2.92 if Im correct? With 400hp you should look into lower gears while your at it if you wanna be able to handle the power.
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
QuadraJet carb more than enough for 400hp
best value ... Delivered to your USA door for about $3200 ... all this
http://www.yearone.com/Serverfiles/p...archid=6446007
* Horsepower: 400+
* Torque: 400+ ft/lbs
* Compression ratio: 9.7:1
* Dyno-tested: Yes, includes 8" balancer & 14" flexplate
* Dyno sheet: Included with engine's output
* Vacuum produced: 12hg @ 800RPM
* Recommended fuel: 92 octane
* Max recommended RPM- 5800
* Block: Seasoned 4-bolt iron
* Crankshaft: OE cast iron
* Pistons: Hypereutectic
* Connecting rods: Powdered metal
* Camshaft- Hydraulic roller with YearOne proprietary specifcations
* Rocker arms: Stamped steel 1.6:1 ratio
* Cylinder heads: Ported Dart Iron Vortec
* Valves: Stainless steel 2.02 int/1.60 exh
* Valve springs: Heavy duty
* Bore x Stroke: 4.04" x 3.48"
* Intake manifold: Dual-plane aluminum
* Oil pan, timing cover, valve covers included
* Engine fasteners: High tensile strength
* Warranty: 12 mth/12,000 mi
best value ... Delivered to your USA door for about $3200 ... all this
http://www.yearone.com/Serverfiles/p...archid=6446007
* Horsepower: 400+
* Torque: 400+ ft/lbs
* Compression ratio: 9.7:1
* Dyno-tested: Yes, includes 8" balancer & 14" flexplate
* Dyno sheet: Included with engine's output
* Vacuum produced: 12hg @ 800RPM
* Recommended fuel: 92 octane
* Max recommended RPM- 5800
* Block: Seasoned 4-bolt iron
* Crankshaft: OE cast iron
* Pistons: Hypereutectic
* Connecting rods: Powdered metal
* Camshaft- Hydraulic roller with YearOne proprietary specifcations
* Rocker arms: Stamped steel 1.6:1 ratio
* Cylinder heads: Ported Dart Iron Vortec
* Valves: Stainless steel 2.02 int/1.60 exh
* Valve springs: Heavy duty
* Bore x Stroke: 4.04" x 3.48"
* Intake manifold: Dual-plane aluminum
* Oil pan, timing cover, valve covers included
* Engine fasteners: High tensile strength
* Warranty: 12 mth/12,000 mi
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
Gears should be your first upgrade on an '81 before you even touch the engine. Then the crate motor listed above with the stock carb (if its still there) would be the best bang for the buck. Nothing wrong with doing a 383 like you plan though. Just don't use an Edelbrock carb.
Thread Starter
Advanced
Joined: Nov 2011
Posts: 64
Likes: 0
From: Medford OK
Gears should be your first upgrade on an '81 before you even touch the engine. Then the crate motor listed above with the stock carb (if its still there) would be the best bang for the buck. Nothing wrong with doing a 383 like you plan though. Just don't use an Edelbrock carb.
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
For me, it isn't the top end but how it feels around town and on the freeway. Changing to a higher numerical rear gear (my '80 has a 3.55 from the factory) gives a rush of acceleration when I need it or when I want to show off a little. With a hotter cam you'll need a better gear for torque multiplication if for no other reason.
Thread Starter
Advanced
Joined: Nov 2011
Posts: 64
Likes: 0
From: Medford OK
$$$
It looks like around $8,000 is going to my budget. I live in a pretty small town and one of my buddies works for a racing engine builder in a bigger town nearby. He has access to balancing equipment and everything but he does all the work in his own shop on the side for projects like this. Since I'm planning on over 400 hp a new clutch will be needed. Any suggestions?
Racer
Joined: Nov 2011
Posts: 261
Likes: 1
From: Montgomery TX
It looks like around $8,000 is going to my budget. I live in a pretty small town and one of my buddies works for a racing engine builder in a bigger town nearby. He has access to balancing equipment and everything but he does all the work in his own shop on the side for projects like this. Since I'm planning on over 400 hp a new clutch will be needed. Any suggestions?
