This video has a a title that will bring up a lot of discussion and controversy. I got the quote from Tim Meyer's T shirt, for his TrackBoss Performance Products business. Although his shirt says Most outlawed Engine in history, I added Racing in History, more pertinent to what we are discussing. In this video I discuss what made the 351 Cleveland the most Outlawed Engine, specifically the 4 V cylinder heads. The iron 4V heads came from the Boss 302, that they ran and developed for the Trans Am racing series. The Ford Mustang, and Cougar were Fords flagships. Ford won the 1970 Trans Am season with driver Parnelli Jones running a Mustang. I have heard and read that the Boss 302 heads were developed back in late 67 early 68. The Cleveland started development around the same time, as I have the first Cleveland Block, with a date code of 1968. In fact that the Cleveland 4V heads I show, are really Boss 302 heads, with the water passages brazed closed.
I made the statement in the title, because the Cleveland has been penalized in every type of racing, and even the Engine Masters series. During the Pro Stock years, the Cleveland was penalized with the most weight per cubic inch, of any other engine combination. It had to carry more weight than the Hemi. The key to success in pro Stock, was not only the drivers, but the Ford 351 Cleveland's canted valve cylinder heads. They are a canted valve head, with the BBC being the closest in similarity. The valves are canted, and open away from the cylinder wall, and decreasing the effects of valve shrouding immensely. The ports are huge in comparison to other small cubic inch displacement engines of the time. the Boss 302 in 1969, initially ran 2.23 inch intake valves, in 1969, they were changed in 1970 to 2.19 inches. The standard intake valve size for the 4V heads. The exhaust were 1.71 inches for both Boss 302, and Cleveland 4v. They flow like gangbusters from the factory. They had screw in studs for adjustable valve train, as Boss 302, ran a solid lifter cam. Intake port was made to work above 4000 rpm, lower rpm, caused the air flow to have decreased velocity, and not the best low end torque. As seen in video they make intake port fillers to effectively raise the intake port track. Increasing the velocity and airflow. Darin Morgan told me the port fillers can add 30 ft lbs of torque, the fin that you see in the intake, is a band aid, as per Darin Morgan. he did say the fin placed in the port, does allow for pick up of 15 ft lbs. of torque.
In this video you will I will explore their main design flaw, the somewhat shortened and cramped exhaust port, that was made to fit shock tower cars, specifically the Mustang and Cougar. What the Pro Stock racers did, or have done was cut off the exhaust port, and add an aluminum plate that mounted on what was left of the bottom of the exhaust port, and secured with head bolts. This effectively raised the exhaust ports 1 3/4 of an inch. The aluminum port had many different shaped ports, from square to oblong, and round being the most popular shape . The plate was ported, and the short turn could be modified extensively. From reports, they say the plate added 20-25hp, I bet it added more like 40-50hp. Not sure who did this first, but did have a subscriber, wished I could find his info. He said Wayne Gapp, came to him, when he was working for Ford in 1970, with instructions and blue prints of cutting off the exhaust port. Not sure how true this is, but have heard nothing to dispute this.
The Ford 351 Cleveland is the most outlawed engine in history, If you find this quote, or where there this came from, let me know, and I will hook you up. I know that quite a few will dispute this, but that is what starts discussion. I would like to know who was the first to cut off the exhaust port and perform this modification.
22 сен 2022
