New heads on the way for my Dart, few changes

What do you realistically think the 1 7/8 vs 1 5/8 are worth on a deal like that amx Rod posted? Worth a full tenth on a motor like that maybe ?

i really dont know. I have never( until now) had a small tube on such a motor.
My guess is the better the head, the more its gonna like a better header. This head, while still small, is fully 200cc, lot bigger than an eddie. So its not gonna “ lay down” as quickly on the big end as for instance what i now have.
I have been 6.78 with what i have, but only 10.77. Its definitely wheezing on the big end. A bunch. 6.78 should be much quicker in the 1/4. I have the car geared to run 1/4, so it isnt that.
The shortblock that guy has those heads on isnt trick or anything. Its 11.5 compression typical stroker. It does have a nicely done super Victor on it, but the cam isnt huge at all. 263@50. And that is the first time out with it, new everything, motor, trans, vert, everything.
That car has some huge tires on it. Has to be some ET in running much smaller meats on it and not dragging those steamrollers down the track..lol