There are several good aftermarket aluminum head designs today, and Trick Flow Specialties Twisted Wedge head is great one! These heads can add roughly 50+hp out of the box to your L-69 and are fully smog legal. They aren't cheap, but by the time you spend money getting your stock heads ported, refinished, and all the valve work done you will have spent nearly the same amount as simply purchasing a set of these heads.
They don't make a specific head for the 305, but that's OK, since the narrow heart-shaped combustion chambers and modifed valve angles will clear the walls of your smaller 305 cylinders without a problem! Don't worry about switching from a 58cc combustion chamber to the 64cc chamber on the TFS heads, they more than make up for the small drop in compression you lose.
The Edlebrock heads are also a good choice, but they come with 72cc chambers and smaller runners, and do not feature the narrower valve angles to adequately clear the piston walls with a stock bore. While not a bad head choice, they typically only gain 35-40hp on the L69 and cost about $100 more than the TFS heads in fully assembled trim.
Estimated Cost $850
A Dual Electrictric fan with a shroud can save you power (5-10hp) if your cooling system is adequately designed. There are several brands available and none seem to be very remarkably better than any other so I would say price and warranty should be your only influencing decisions on which one to buy. Since electric fans are typically less efficient than the stock fan, it is a good idea to upgrade your cooling system with a larger radiator or aluminum (etc.) when using an electric fan.
It should also be noted that you can convert a GM electric Fan unit from the Camaro, or GNX for use as well, but this requires the fabrication of your own custom shroud.
Estimated cost $70
ECM Chips from various aftermarket Manufacturer's cannot control much with a carbuerated engine, but it does modify the Air/Fuel Ratio and improves the spark curve. Remember that on a carbeurated engine, there is not much one of these chips can control and gains are usually very small however, on the 87-88 SS's the electronically advanced distributer is a good reason to consider this option.
Usually one of these performance chips give excellent results on fuel inmjected engines, however this is an option that you may wish to pass up on the 83-86 models. I have found that the ADS chip for the 350 H.O. certianly provides a small difference, if not eye opening. If your have an 87-88 SS and have swapped in a 350 or larger engine you probably want to run one of these chips as the Timing on these vehicles are controlled by the ECM and the stock chip
isn't adequate for larger displacement engines with an eye toward performance. Estimated cost $110
A Transmission Cooler is mandatory if you want to send more than 300lbs-ft. of torque through your tranny. I personally like the B&M Super Cooler as it features a much improved design over the tubular pass designs of most other brands. Unless your radiator does not have a trans-cooler built-in you should run your lines through the radiator trans-cooler first and then into your aftermarket tranny cooler, this will aid in cooling your trans down much better than just the aftermarket trans-cooler by itself!
Estimated cost $45
Light alloy wheels can shave a few 100ths of a second at the track, and the lower unsprung mass aids in handling and traction. Make sure you order rims with the correct backspacing and offset, as well as bolt pattern! The Generally accepted backspacing on the SS is 3.5" - 4" other wise you will be required to notch your frame or add wheel tubs. The offset depends on your backspacing but it generally should be 5mm-19mm positive offset. The bolt pattern should be 5x4.75".
About the widest rim you can fit is a 10" rim but the disadvantage of this is that it requires a 3.5" backspacing and a 19mm positive offset which just manages to squeeze a 275/50 tire under the rear with a "rolled" wheel well lip.
Estimated cost $120ea.
An Aluminum Water pump from EdleBrock wieghs half as much as the stock waterpump, and increases coolant flow by 30% or more. This will help you cool down the engine which will probably get very hot during 90+ degree days in the summer. A cool engine always makes better power, and with the redesigned impellar of the Edlebrock pump you can pick 4-8hp with this simple bolt-on swap. There are other good Hi-volume pumps available as well but the Edlebrock unit is the only one I have found to offer a "long-neck" version that
doesn't require the use of spacers. Estimated cost $150
This Completes the STAGE 3 buildup of the 83-88 Monte Carlo SS
Using the Rebuilt Carb, Edlebrock Intake, Crane Cam, Crane Rockers, MSD Ignition, Auburn Differential.