Our good friends over at Dart Heads never cease developing new products for the drag racing and performance marketplaces. At PRI in 2012, they had three different cylinder heads on display that are fresh for the 2013 season, each of which are poised to be prime movers in the marketplace thanks to their design features.We also covered the upgrades to Dart’s aluminum Chevy and Ford small blocks,in addition to their new LS block, in another post from PRI. Check it out here.
Their Big Chief big-block Chevrolet heads are cast from virgin 355-T61 aerospace alloy and feature huge 402 or 424 cc raised intake ports and an 18-degree rolled valve angle to provide superior flow. The CNC-porting and huge 2.40-inch intake and 1.90-inch exhaust valves aid in that area as well. They are available in both 4.500-inch and 4.600-inch bore space versions and can be ordered in many different configurations. As these heads are state-of-the-art pieces of wizardry, Dart recommends giving a call to their tech line before you place an order. Any engine build of the caliber that would require a serious-flowing set of heads like these will benefit from their technical assistance during the ordering process.
The next big piece they had at their display was the new Pro 1 LS1 CNC cylinder head. These bad boys are cast from the same 355-T61 alloy, and use beautifully-contoured CNC-machined 250cc cathedral-style intake ports to achieve maximum airflow. The 68c combustion chambers have also been CNC’d for consistency and performance, while the chamber shape has been designed to promote flame travel. Manganese bronze valve guides and hardened valve seats are standard fare, and there has been additional metal built into the casting above the ports that corrects a notorious issue and provides room for future upgrades. These heads use a 2.08/1.60-inch valve package, and as such, Dart recommends that they be used on 4.00-inch bore and larger engines.
Also in their 2013 cylinder head lineup is the new Pro2 380cc big-block Chevy CNC cylinder head. Just like the rest of Dart’s lineup, they are cast from 355-T61 alloy right here in the USA. They are designed to be a bolt-on to existing BB setups, but do feature a 2-degree rolled intake valve angle to help promote flow. The 121cc combustion chambers have a heart-shaped design and are CNC-machined for consistency. The Dart engineering team raised the spark plug location in these castings to improve flame travel in the chamber to aid in a more complete burn of the mixture. In a nod to the aftermarket porting business, they’ve also seen fit to include brass tubes in the adjacent head bolt holes to allow the ports to be widened without fear of breaking through the casting.