The factory EFI does not like a narrow lobe separation on the cam.
I have a 97 Dakota 318 with the following mods running on a hypertech tuner
Cam 260/264 114 lobe separation .487" lift intake . 496" exhaust with 1.7 roller rockers
M1 intake
ported stock TB
ported stock heads @.500" lift 243 intake 180 exhaust
edelbrock shorty headers
flowmaster catback
This combo was good for 247rwhp/265 rwtq with no loss of drivability or fuel mileage (to my amazement!)