PI heads vs A429 heads

Trying to find more info on the differences between the two heads. and had some questions:

1. What kind of gain can one expect from a set of stock PI heads vs a set of A429 heads besides weight.

2. If i have a set of PI heads now, can the valve and valve train be swapped over?

3. I have currently a set of PI heads on a 466 10.5 compression, pump gas, lunati 61605 cam and supporting parts, wieand stealth. Is there anything I should possibly change out, maybe intake to a 4500 victor intake, ect. (have a domi that will go on if i swapp heads)?

Frank

How does it run now and what is it in ? Stock PI heads flow around 300/165 I think..A429 flow a bit more and have smaller chambers.

runs fine havent had it to the track yet, its in a 2002 mustang.

rmcomprandy wrote:First thing is your compression ratio will get raised about a point and the valve to piston clearance will be about .090" less.
Performance wise ... the A429 heads would blow away any PI heads on the same engine with similar head modifications.

So basically a increase from the compression increase and better flow. and the weight savings will be nice also

rmcomprandy wrote:First thing is your compression ratio will get raised about a point and the valve to piston clearance will be about .090" less.
Performance wise ... the A429 heads would blow away any PI heads on the same engine with similar head modifications.

Do the pistons need to be changed, or can one get by with flycutting for more clearance, if the pistons even have enough material to do so? Would a major increase in power also require a cam change? Is pump gas even something to consider with the increased compression? I am not considering doing this myself... just curious, and never researched these heads as they aren't in my gameplan.

longroofracer wrote:

rmcomprandy wrote:First thing is your compression ratio will get raised about a point and the valve to piston clearance will be about .090" less.
Performance wise ... the A429 heads would blow away any PI heads on the same engine with similar head modifications.

Do the pistons need to be changed, or can one get by with flycutting for more clearance, if the pistons even have enough material to do so? Would a major increase in power also require a cam change? Is pump gas even something to consider with the increased compression? I am not considering doing this myself... just curious, and never researched these heads as they aren't in my gameplan.

i know myself personally have plenty of PTV clearance....I guess a cam change would help bring more power with the better airflow.....Pump gas and alum heads is USUALLY good to 11.5 to 1

PTV changes with duration as much so as with lift. With more duration, the valve is opening more while the piston is at the top of the stroke. I know the Diamonds are cut deep enough from the factory to be compatable with very aggressive lobes. 11.5:1 C/R and aluminum heads running on pump gas takes a person who knows his beans with tuning. I would not personally try it myself, with the crappy pump swill sold around here. I am not a good tuner though.

run down of what i have now

d1 block 30 over
zero decked
srp forged flat op pistons
je rings
cat forged h beam rods
D2OE heads
crower roller rockers
comp cams spring kit
felpro gasket kit
Lunati 61605 cam and lifters
stealth intake untouched
edlebrock 750 carb
procomp water pump
frpp timing set
short tube headers into 3 inch pipe and pypes pro race mufflers
quicktime bellhousing with t56 trans and 3.73 gear in back

wanna trade out the pi heads with a429 heads victor intake and 1050 dominator carb, maybe a header swap at some point.

future upgrades after- 9 inch rear and c4 trans

car is a 2002 mustang
kirkey front seats, alum rear seat delete, all original wiring and electronics stripped, no heat ac or stereo
fuel cell in trunk (rci alum 16 gallon)
rear has 373 gears, eaton posi, alloy usa axles 31 spline,
greg weld wheel
mt drag radials 275/50/15 iirc
6 inch cowl hood
arc8000 control panel, msd 6al2 box
aeromotive ss fuel kit with -8 to and from regulator

maximum motorsports rear lowers (adj wieght jackers)
granatelli k member with mm arms adn coil over kit
manual steering rack and steering shaft (flaming river)

i think thats most of it

quick clarification, the a429 cobra jet are stock location valves, and no the canted valve of the scj or p51 right?

frank13 wrote:quick clarification, the a429 cobra jet are stock location valves, and no the canted valve of the scj or p51 right?

A429 heads will work., why I say will work , can,t say the same , some had the valve placement a little off