THese: http://www.summitracing.com/parts/tf...view/make/ford


or These:http://www.summitracing.com/parts/tf...view/make/ford

I dont see what the difference is. They are both 61 cc with the same lift and the same size valve...What is the difference?

 

so here is what I gather..

The first set, Has larger rocker studs.
a dual spring
a spring that is a little narrower
It has a lift with the potential of .600 in lue of .550

So even though I have a cam with a max lift of .538 i assume i should go with the track heat heads)the first listed) because of the dual spring which has a higher lbs rating than the latter..


Am I on the right track here?

 

I think its largely the spring size, and I dont know why they did that unless some new brand of spring likes a smaller wire size at a larger OD or something?

Although the "Track heat" heads mention CNC porting and the other heads dont mention it?

I would call Summit, it may just be an update to the part number and the older one is NLA.

 

i don't think either head has been CNC'd.

basically one's more of an emissions type head if that's the right terminology.

The track heat heads generally don't have the heat crossover. It's a passage that moves exhaust gas heat to the intake to heat it up. It's that little port in the heads at the center. Some also have a lengthwise port that connects each exhaust port to the end of the head. The track heat may not have that either.

i don't know if the valves are longer on the track heat and that's the primary reason it's capable of more valve lift or what (of course the springs have to match to the required installed height...).

 

I'd use the Trick Flow website to pick the heads. They have much more info in a better format than the Summit page.