What was the thinking that developed 1/2 flathead and 1/2 overhead valve

[pelago]

J ust wondered how this evolved when the engine came out. up to that time it was a flathead and then the new engine came out that was half and half. ford came out with a overhead v8 in fall of 53, the 1954 model. chevy had overhead valves,, but the willlys was half and half, curious

[gmwillys]

The simple answer to this question was that the designers wanted more power, without increasing the size of the foot print of the block itself. Willys was notorious for finding something that works, then leave it alone. For instance, the Willys wagon, no major design changes from 1946 through 1963. It wasn't until Kaiser came into the picture that some major changes came about. The 134 i4 didn't really change all that much from the Go Devil days through the Hurricanes, with exception to the head design, (1946 through 1971). The changes to the Hurricane engines were bigger valves used with the F head set up, with the intake over the exhaust, more room was made for the bigger valves. Compression was raised from 6.5:1 to 7.5:1, due to the reduction in size of the combustion chamber. Horse power was raised from 60hp to 75hp, with the F head upgrade. Torque was increased from 105 lb-ft to 115 lb-ft.