With the increasing number of members here lately, I figured we should put together a nice organized thread with a performance "mods" list for 2nd gens. I'll need suggestions to add to this, and I'll add them to the main post when you suggest them. This is all out of my head, so if you see any errors please let me know so I can fix it!
Detailed Sections will be broken off into their own FAQ thread and linked from here (such as the rear disc conversion).
Spax Springs (1.3 inch drop)
King Springs (1.5?? inch drop)
Eibach Pro Kit (1.3 inch drop) EIB-4023.140
B&G Springs (1.6 inch drop)
Suspension Techniques (Drop Unknown) S-052B-FR
Ground Control Coilovers (Adjustable Height)
Rumored to exist and have been discontinued
Koni Internally Adjustable
http://www.classicgarage.com (New Old Stock, Discontinued)
Koni Externally Adjustable Rears From 2g Prelude
Discontinued, occasionally show up on eBay.
See the Koni Part Number FAQ: https://www.3geez.com/forum/2geez-tech-performance/54639-koni-part-numbers.html
And install HowTo: https://www.3geez.com/forum/2geez-tech-performance/58060-2g-koni-eibach-install.html
Swaybars appear to differ between 82-83 and 84-85 models due to a possible track width increase in 1984.
http://www.addco.net (Possibly Discontinued, stock seems to be dwindling)
http://www.whiteline.com.au (Expensive shipping from Australia, need to find North American distributor)
Honda OEM Rear Swaybar
If your 2nd gen came with no rear swaybar, the 84-85 LX Hatchback came with a rear sway that might work on base models. The 85 SEi also has a rear swaybar that will fit sedans if you also use the SEi control arms.
Weber Progressive Kit (DGEV 32/36)
Make sure you specify if you have an 82-83 or 84-85 engine! Adapter plates are completely different and are not compatible!
HowTo is nearly identical to the 3rd gen: https://www.3geez.com/forum/frequently-asked-questions/38161-weber-32-36-34-38-a.html
For custom carbs, same principles apply, manifold modifications recommended to supply fuel to CVCC auxiliary chambers.
Some headers have been seen on eBay for the 82-83 EK1 engine. 1981 and earlier EK1 headers will not fit. More information is needed.
Any 4-2-1, or shorty 4-1, header from a 2nd gen Prelude, or 3rd gen Accord will also fit the 84-85 Accords with the ES, ET or EZ motors. These will require modifications to emissions control systems, and probably will not bolt to the factory exhaust system. Welding to the factory exhaust will be requred, EGR and air suction systems will either need to be deleted, or pipes modified to reconnect properly to the new header.
Available exhausts are listed in the 3rd gen section here:
The only ones that won't fit are any of the 4-1 long tube headers. These do not have enough clearance between the front crossmember and header. The 4-2-1's are very close as it is, and some people report that they hit slightly when the engine rocks which may require some crossmember grinding.
Colt Cams will do custom grinds on these camshafts. Cams are not interchangeable with earlier pre-1982 EK1 engines due to port layout change. Other companies listed in the 3g Accord camshaft FAQ may do grinds on this cam as well.
Not many people (anybody?) has done camshafts for these cars. I suspect a 2g Prelude with a 1.8 motor will have a slightly more aggressive cam for a bit more power. Colt, Delta and anybody who does grinds for 3rd gens should be able to grind a cam for a 2g Accord. A cam spec from a 3g should yield similar results in the 2g Accord.
If you have an 84-85 Accord with CVCC (ES2 motor), your only swappable, OEM cam will be from a 2g Prelude with CVCC as well (ES1 motor). If you have a non-CVCC motor (ES3, EZ or ET), A20 cams and A18 Carb'd cams might be options. A custom grind is highly recommended though. Look to 3g Accords for grind specs.
For any motor, the most common mild grind is a grind somewhere around 270. Typically it offers the best streetability, and good top-end power increase.
3rd Gen Accord Camshaft FAQ:
Engine and Head Swaps
This is actually pretty extensive. I'll get to this later.
See gear ratios here: https://www.3geez.com/forum/2geez-accords/59778-2g-gear-ratios.html
Any 1.8 liter Prelude transmission (ES1 or A18) will bolt into a 2g Accord directly.
A20 transmissions will bolt to the motor, and allow usage of bigger flywheel and clutch, but it has bigger driveshaft splines. You'll need A20 starter and '85 SEi axles and hubs or see the Axle Swap Info thread here: https://www.3geez.com/forum/2geez-accords/51211-axle-swap-info.html
The A20 transmission swap provides no known benefit aside from possibly being slightly stronger. Gear ratios are about the same as carb'd ES2 transmissions.
Front brakes can be swapped from 86-87 Accords. They have slightly thicker rotors and bigger pads and calipers. All you need are the rotors and calipers. This also means that the JDM F1 Edition Accord two-piston calipers bolt right in. They also use the same pads as the rest of the 86-87 Accords. You may need to modify (bend or remove) the backing plates so they don't rub on the thicker rotors.
Rear discs from the 2g Prelude (DX or Si) swap directly on to the rear spindles. HowTo Here: