Sam's Offroad has sold and installed hundreds of these kits and recommends the following accessories for a smooth installation with better fuel Economy & Performance.

HEI Distributor for Jeep 258 Sam's Price $179.95 Top of your Howell EFI conversion with an HEI Ignition System. Comes complete with Cap, Rotor, Coil & Taylor 8MM plug wires. Guaranteed better than the Motorcraft System!
K&N 7" Air Filter  Sam's Price $79.95 When installing the Howell Fuel Injection kit on your Jeep or Toyota your old air cleaner will not work. We suggest going with the K&N seven inch diameter air cleaner. This air cleaner gives you better flow plus you can close your hood without any clearance problems. Comes with extended air cleaner stud & wing nut too!
K&N 11" Air Filter  Sam's Price $89.95  We suggest going with the K&N 11" diameter air cleaner on V8 EFI Applications. This air cleaner gives you better flow plus you can close your hood without any clearance problems.
K&N Filter Recharger Kit    Sam's Price $16.95 Under normal street driving conditions we recommend cleaning your filter every year with K&N's cleaning solution. This is all you need to clean and re-oil your K&N filter.

Dual Fan Control Kit Sam's Price $79.95  Uses 190 degree cylinder head temperature sensor and Heavy Duty GM fan relay to operate electric cooling fan automatically.
Borla Headers 258 Jeep Sam's Price $569.95  Borla 17053 Headers, Shorty, Stainless Steel, Natural, Jeep, CJ7, 258, L6, Each, 1981 - 86 BORLA Cat-Back™ exhausts feature patented, straight-through and multi-core technology to unleash hidden horsepower. Increased exhaust velocity adds power, driving excitement, fuel economy and the distinctive BORLA Sound of Power respected by motoring enthusiasts everywhere. Each system is built from premium austenitic stainless steel, superior to T-400 series knockoffs, to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow and power, and precision computer-controlled CNC manufacturing ensures an accurate fit. Best of all, BORLA stands behind every system with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.
Heated 0xygn Sensor GM 4 Wire Oxygen Sensor Sam's Price $74.95 ted This sensor is needed when running headers.  The reason is that exhaust gases cool down at idle a lot more with headers than their counter part the stock exhaust manifold.  When this happens the regular 02 sensor will not activate because the temp reading is to low thus making the ECM make the engine run to rich.  In short the heated 02 sensor tricks the computer to run correctly.
GM Valve Cover Ventilation Spacer Sam's Price $24.95 ted Crank Case Ventilation Ring - You will not be able to use your stock air cleaner with the Howell EFI Conversion kit. When removing your old air cleaner you will notice a hose that hooks into it and then hooks into the back of the valve cover. You will need to retain it so this part will let you hook up the hose. It fits between the air cleaner and throttle body.