Smogger Dyno - 420+ HP

The following buildups are based on most people's expectations for street and towing engines, and are intended as a reference point. We tried numerous combinations, and chose these examples as representative of the most common type of buildups. Those of you looking for more serious Pro Street and race combinations should keep in mind that we have many dyno and track proven combos for you as well. A sound bottom end is important in any buildup, and for those wishing to build serious performance packages now (or in the future based on the bottom end you build now) should consider the 10:1 test engine with forged rods and balanced rotating assembly as the minimum short block specs. Remember that we are always happy to set you up with a custom tailored parts package to suit your current and planned future needs with your budget in mind. Package deals are usually priced with a discount included, as well.

Lets start with the advantages of using the 472/500 engine family as a basis for your next engine. This engine family has earned a reputation for longevity and power, partly due to the high initial build quality. You are starting with an engine with tighter specs than many new ‘high end’ cars, to include the squareness and uniformity (lack of casting shift) usually expected only in high dollar full race engines, from the bore centers, to the deck surface, to the rotating parts centerlines, to the exceedingly high nickel content of the castings (like a ‘Bow Tie’™ block that costs more bare than your complete core engine). These engines are also very light for their size, being within 60 Lbs of a small block Chevy, while still being tougher and more wear resistant due to the high quality materials and castings. They have numerous other advantages, including easy access to the distributor and oil pump, dry (no coolant passages) intake, individual ports (not siamesed to lower production costs while hurting flow), conveniently angled spark plugs (easy access in the tightest of installations), and internally balanced, eliminating the need (and inefficiency) of external balancing.

For this exercise, we'll go step by step and show you how to gain 120+ HP and 60+ Lb-Ft of torque with a stock short block, keeping things truly street able and running on pump gas. Here at Cad Company, we have dyno tested a large majority of the bolt on combinations for street applications of both the low and high compression 472/500 engines, simply following the clear, detailed installation instructions provided with the parts, and not spending time ‘dyno tuning’ or ‘dialing in’ each combination, to get a true representation of what you can expect by following these examples. Remember that most engine dyno facilities claim up to 10%, or more, gain is possible by spending a day dialing in your chosen combination. Remember to choose your dyno facility carefully, as race engine shop may tend to compromise part throttle drivability on you street car engine for maximum WOT power, and vice versa for a street performance tuner.

We will start with our low compression buildup, and move on to the high compression engine later on. Our low compression short block was based on a ’76 spec rebuild, and was built with 8:1 instead of 8.5:1 compression due to piston modification for later race combos not detailed here. The short block was bored 0.060" over, with 0.002" piston clearance, reconditioned stock rods with ARP fasteners on an OE crank turned .010/.010 (not balanced), and assembled following stock clearance specs using the following parts:

And the dyno says: 493.5 Lb-Ft at 2600 RPM and 302.1 HP at 3600. While it had only dropped to 291.4 HP at 4200 RPM, keep in mind that that is where new (not 100k+ mile, 30 year old) stock spec springs begin to show valve float. At this point, the Edlebrock 2115 intake (Pg 21) was installed, retaining the stock Q-jet carb (Pg 22). While the stock rubber end gaskets work fine with OE intakes, they tend to split with the installation of aluminum intakes. A bead of silicone does nicely here. Proper port sealing was assured by using our exclusive high grade composite intake gaskets (Pgs 10, 21). (Note: this combo likes more ignition advance than the stock combo). The results were +20 HP at peak, but our torque band was moved higher, and we lost 35 Lb-Ft at 2000 RPM and 7 LbFt at the torque peak. Both with the 2115 and back to the stock intake for testing an experimental (now in our regular lineup as the CTA 120 TD) RV cam (Pg 12), we found around 15 Lb-Ft and 25 HP either way. This thing made 512 Lb-Ft and 323 HP (same peak HP as the 2115 with the stock cam, with the torque peak at 2700 RPM) by itself, still idling smoother than most stock 454s.