Modifying automatic c4
Thread Starter
Instructor
Joined: Dec 2023
Posts: 192
Likes: 30
Modifying automatic c4
Is there a point to do this? This is the first “cooler” car I’ve bought and honestly don’t care for a manual like most people need. But is there a point to modify a fully stock automatic 84’ corvette (other than exhaust that’s already done). Like I said it’s the first car I’d be doing anything to and was just wondering
Pro
Joined: Mar 2006
Posts: 517
Likes: 142
From: Caribbean/Florida
All depends on what YOU want out of a car...
Most people love the handling of the 84' Crossfire cars but are not happy with the 205HP and 290LBS of torque.
Thus, 25 more horsepower to equal an 85' at 230HP greatly improves the way your car feels and performs. The suspension in your car and the aerodynamics of the body can handle much more horsepower...
The Callaway Twin Turbos made over 400HP the ZR1 405HP in stock trim, so theoretically your car would or could easily handle 500HP. Now the fun factor and the performance will only increase with the addition of extra horsepower...
The LT1 cars with 300HP to the LT4's 330HP is probably a good overall spot for your chassis.
For every 30HP increase the performance basically matches the jump in performance year over year during the C4 production run.
Most people love the handling of the 84' Crossfire cars but are not happy with the 205HP and 290LBS of torque.
Thus, 25 more horsepower to equal an 85' at 230HP greatly improves the way your car feels and performs. The suspension in your car and the aerodynamics of the body can handle much more horsepower...
The Callaway Twin Turbos made over 400HP the ZR1 405HP in stock trim, so theoretically your car would or could easily handle 500HP. Now the fun factor and the performance will only increase with the addition of extra horsepower...
The LT1 cars with 300HP to the LT4's 330HP is probably a good overall spot for your chassis.
For every 30HP increase the performance basically matches the jump in performance year over year during the C4 production run.
Thread Starter
Instructor
Joined: Dec 2023
Posts: 192
Likes: 30
All depends on what YOU want out of a car...
Most people love the handling of the 84' Crossfire cars but are not happy with the 205HP and 290LBS of torque.
Thus, 25 more horsepower to equal an 85' at 230HP greatly improves the way your car feels and performs. The suspension in your car and the aerodynamics of the body can handle much more horsepower...
The Callaway Twin Turbos made over 400HP the ZR1 405HP in stock trim, so theoretically your car would or could easily handle 500HP. Now the fun factor and the performance will only increase with the addition of extra horsepower...
The LT1 cars with 300HP to the LT4's 330HP is probably a good overall spot for your chassis.
For every 30HP increase the performance basically matches the jump in performance year over year during the C4 production run.
Most people love the handling of the 84' Crossfire cars but are not happy with the 205HP and 290LBS of torque.
Thus, 25 more horsepower to equal an 85' at 230HP greatly improves the way your car feels and performs. The suspension in your car and the aerodynamics of the body can handle much more horsepower...
The Callaway Twin Turbos made over 400HP the ZR1 405HP in stock trim, so theoretically your car would or could easily handle 500HP. Now the fun factor and the performance will only increase with the addition of extra horsepower...
The LT1 cars with 300HP to the LT4's 330HP is probably a good overall spot for your chassis.
For every 30HP increase the performance basically matches the jump in performance year over year during the C4 production run.
Pro
Joined: Mar 2006
Posts: 517
Likes: 142
From: Caribbean/Florida
No problem with the automatic... we built a friends 84 automatic and it would beat me out the hole and to the 60 foot mark every time. I have a 86' 4+3...
In a drag race setting the automatic is the most consistent car, repeatable performance... Today's cars are nearly all automatic... so this is the current reality as the slush box shifts faster than the human can shift gears...
In a drag race setting the automatic is the most consistent car, repeatable performance... Today's cars are nearly all automatic... so this is the current reality as the slush box shifts faster than the human can shift gears...
Thread Starter
Instructor
Joined: Dec 2023
Posts: 192
Likes: 30
No problem with the automatic... we built a friends 84 automatic and it would beat me out the hole and to the 60 foot mark every time. I have a 86' 4+3...
In a drag race setting the automatic is the most consistent car, repeatable performance... Today's cars are nearly all automatic... so this is the current reality as the slush box shifts faster than the human can shift gears...
In a drag race setting the automatic is the most consistent car, repeatable performance... Today's cars are nearly all automatic... so this is the current reality as the slush box shifts faster than the human can shift gears...
Pro
Joined: Mar 2006
Posts: 517
Likes: 142
From: Caribbean/Florida
The Intake manifold is number 1 (I think some guys just use to buy a carb intake and make a plate to drop the CFI throttle body on it)..., Headers and dual exhaust would be number 2... a good cam or just some very nice springs and 1.6:1 full roller rocker arms... number 3
If its an automatic, 2,400 to 2,600 stall converter, number 4, and 3.45 to 3.55 rear gear ratio change Number 5, maybe a shift kit in the tranny and upgrade to the 89' transmission servos, number 6... modern sticky tires like Nitto... number 7
Lastly with the 84' I think they have forged pistons and only 9:1 compression ratio so a plate Nitro-Oxide system with 100Hp jet for fun and 150hp jet for racing...
Of course you will want to do this on a fresh bottom end, and if needed a little more cubes with a rebuild to 355 Cubic Inch, (If you go this far you may want to get a cheap 383 rotating assembly and get the extra cubes and power that comes with it).
Buy the best plugs, wires, cap and rotor and coil you can buy... a good tune up will optimize all improvements...
If you did half these things the car will come to life, if you did 3/4 even more fun... all the above, money allowing, it would be a total blast and smile generator, it get addictive! Remember the 2023 C8 Z06 runs 11.2 in the quarter mile so any lighter weight c4 with 400 gross horsepower should get you into the high 11's.
Good Luck...
If its an automatic, 2,400 to 2,600 stall converter, number 4, and 3.45 to 3.55 rear gear ratio change Number 5, maybe a shift kit in the tranny and upgrade to the 89' transmission servos, number 6... modern sticky tires like Nitto... number 7
Lastly with the 84' I think they have forged pistons and only 9:1 compression ratio so a plate Nitro-Oxide system with 100Hp jet for fun and 150hp jet for racing...
Of course you will want to do this on a fresh bottom end, and if needed a little more cubes with a rebuild to 355 Cubic Inch, (If you go this far you may want to get a cheap 383 rotating assembly and get the extra cubes and power that comes with it).
Buy the best plugs, wires, cap and rotor and coil you can buy... a good tune up will optimize all improvements...
If you did half these things the car will come to life, if you did 3/4 even more fun... all the above, money allowing, it would be a total blast and smile generator, it get addictive! Remember the 2023 C8 Z06 runs 11.2 in the quarter mile so any lighter weight c4 with 400 gross horsepower should get you into the high 11's.
Good Luck...
Pro
Joined: Mar 2006
Posts: 517
Likes: 142
From: Caribbean/Florida
The 350 Cubic Inch Small Block Chevy has the most aftermarket parts support in the world... The Two piece rear main-seal block, was used from
1967 to 1985... all bottom end parts will work... Forged Crankshafts, I Beam connecting rods, Pistons, rings bearings, camshafts, valvetrain, heads will work on your car, from cheap economy rebuild parts to many thousand dollars high performance rotating assembly, balanced and blueprinted... you can bore and stroke the motor as well... You can build from mild to wild... Bullet proof and can be abused for years! So any hotrod shop can sell you parts and a good machine shop can build what every you want. The number one trick most owners did to the crossfire was jerk the intake off and slap a carb and manifold on there in its place, no more crossfire restrictions and again this route would be sky is the limit on what you can chose from... personally I prefer the challenge of improving what the factory built...
Cheers and Good Luck
1967 to 1985... all bottom end parts will work... Forged Crankshafts, I Beam connecting rods, Pistons, rings bearings, camshafts, valvetrain, heads will work on your car, from cheap economy rebuild parts to many thousand dollars high performance rotating assembly, balanced and blueprinted... you can bore and stroke the motor as well... You can build from mild to wild... Bullet proof and can be abused for years! So any hotrod shop can sell you parts and a good machine shop can build what every you want. The number one trick most owners did to the crossfire was jerk the intake off and slap a carb and manifold on there in its place, no more crossfire restrictions and again this route would be sky is the limit on what you can chose from... personally I prefer the challenge of improving what the factory built...
Cheers and Good Luck
