Originally Posted by woodsman
Originally Posted by superstreeter
I ran a set of 781 steel heads, with larger valves and some porting, then upgraded to the afr 305s,,,the car ran .15 quicker, pretty disappointing,,so don`t get your hopes up,,I think your going to need an extra 130 hp to get that goal, I have found that once you get into the 10s - 1/4 mile,,it takes about 20 hp to get an extra 10th
superstreeter we are think about changing heads on my brothers truck how much HP do we need to shave 3/10th.
After giving this more thought, probably not every change a person makes to his combination will be the same. what I said earlier was my gain with the change, other heads being changed to the 305cc may make more or less HP, changing other items on a vehicle can make big gains as well, without even changing the horse power level, I put the car on a diet for example, took off 200 lbs,car picked up about a 1/4 second, changed the front disc brakes to aerospace duel piston and lighter rotors, this gained me 1/4 second, lighter wheels, driveshaft, tires, transmission, headers, exhaust, etc...will all make big differences in performance, I did several of these over the winter and picked up a second off my time without even touching the engine. Do a slide rule 1/4 mile - hp test before you change any of these items, and you`ll see, your engine will get credit for more horse power, and it hasn`t changed a thing...( other than the weight difference),It doesn`t seem right but you could start out with a 500 hp car at the beginning and end up with something that shows 600 when your done, but I still think you need more than 10 horse to gain a tenth, once you hit the 10.0 range for 1/4 mile or 6.0 range for 1/8 th ,it takes more