Randy, the Bulldog heads that are on my engine have 2.19/1.81 valves..they are ported and have been flowed...we even milled the heads for 72cc chambers to get a 12.8 compression..the cam was cut to take advantage of the flow numbers..

the larger the opening, the more that's going to get in and duration of course is how long you let all that in and so on...you already knew that...

Im going to say..have the largest valve cut in..

so to take advantage you may need a new cam as well... definitely flow the heads...