It's a hydraulic roller with custom lobes. I think it would be really hard to get the torque down low with a flat tappet. The carb has center hung bowls and metering blocks on both ends. 1.320 venturi, 1.686 baseplate, with special boosters. We just used the 1850 main body to get something small enough to work with. The entry is reshaped and it is re-tapered under the venturis to match a 780 base. We did it with low lift and OE rockers with nothing to fail, with intent for years of service. I've been joking about it being an FE Super Duty. The chamber is really good, and this program finishes it off real nice. 31° timing, huge low lift numbers, flows a little over 300 at .500 lift, 235 exhaust at .500 lift. I don't post everything we do, but this was kind of a fun and different type engine, and I thought it would be of interest to the truck crowd, of which I am a member. I sent Mike some more pics to post. He'll catch me up I'm sure. I'm just an old hillbilly and not smart enough to post all them pictures.
The truck is a '69 F-250 highboy..... more like an F350 on steroids now. The man has owned it for years. It has had the frame reinforced in places, heavier springs on both ends. Not a show truck.....a clean old truck that gets USED. It pulls tractors, heavy trailers, and a 28' enclosed car trailer. Dana 60 in front, Dana 70 posi rear, and a late model GM 5-speed transmission.
