Muscle Mustangs & Fast Fords
Ford Mustang DSS Competition Engine Swap - Project ProCharged Pony - 331 Ways To Waste An LS1
Our DSS Competition Engines SuperPro Bullet finds its new home and gets tweaked by the master of mass airflow meters, Jim LaRocca.
In the last six months, our Midnight Blue Metallic Mustang project car has logged a mere 145 miles. Winter and travel have prevented further accruement, so there is some anticipation of getting the pony up and running. It's been too long since we last rumbled down the road, offering 3,500 rpm worth of Team Bassani to the nearest contender.
That's all about to change as we've successfully swapped in our DSS Competition Engines 331ci stroker short-block with help from Crazy Horse Racing in South Amboy, New Jersey.
Why did we pick a 331-inch motor over many of the other popular stroker kits you may ask? We posed the same question to Tom Naegele of DSS and here's what he had to say:
"Our 331 offers the best combination of rod ratio, piston design and ring package for the given 8.2-inch deck height engine. Some people don't consider the frictional losses, poor ring seal and compromised piston design that the larger strokers create. You can fix the problems associated with bigger strokers by using a taller 8.7-inch deck FRRP block, but that incurs more cost. A 331 is almost 40 hp better at 6,000 rpm than a 347. With the 331, we use a 5.315-inch rod, which allows for better ring placement on the piston and proper space between the top and second ring.
"The 347 is good for heavier cars where extra low-end torque is needed. Early on, many builders were using (and some still use) the wrong piston ring packages. This gave this combination a bad reputation for consuming oil. In some extreme cases, the poor rod ratio can even collapse cylinder walls as it side loads the piston in the cylinder really hard. But a 347 is good for 15-20 ft-lb more torque at 3,000 rpm.
"The 327ci stroker is a 331 with a standard bore. It's not a good choice for big-valve cylinder heads due to valve shrouding. The .030-inch overbore of the 331 unshrouds the valves and the machined block offers torque plate honing that a stock block wouldn't normally have. Both of these attributes are worth up to 40 hp. It's really a non-engine builder's combo as anyone with a toolbox can put one together. But you leave a lot of power on the table.
"The 318/320 was an economical combination we used to build before when modern strokers were still very expensive, but they're kind of obsolete now. When you get into the 355, bigger is not always better. Rod ratio, piston design and ring seal are traded for extra cubic inches. Some builders don't think about what they are giving up to obtain those cubic inches-usually around 40 to 50 hp and some reliability. This kit is not very popular anymore."
With that said, the 331-cubic-inch stroker package made sense to us since we would be using a stock-block. DSS has made great strides in getting the factory iron to survive under three times the stock power output, but it has its limit like anything else.