GT 40 heads ?
01-28-2008, 09:47 AM
#21
3rd Gear Member
Join Date: Mar 2007
Location:
Posts: 636
RE: GT 40 heads ?
i would never tell anyone that you would be fine running "any cam" without checking piston to valve clearance it only takes a few minutes and it could save your motor. a .500 cam with 1.7 rockers would give that cam about .530 lift and from what I here .530 is right on the borderline to hit the piston.just my 2 cents good luck with those heads
01-28-2008, 09:58 AM
#22
5th Gear Member
Join Date: Jan 2006
Location: Puerto Rico
Posts: 3,926
RE: GT 40 heads ?
ORIGINAL: nitrous_bob
oooh.... you might have idle issues on an aod car but maybe not, no w/ .500 lift and 1.7's you will not have to notch them, but .500 is pretty much the magic number. a little bigger and you never know.
oooh.... you might have idle issues on an aod car but maybe not, no w/ .500 lift and 1.7's you will not have to notch them, but .500 is pretty much the magic number. a little bigger and you never know.
Total valve lift and the possibility of Piston-to-Valve problems ARE NOT related. Therefore, there is no magic lift number that will ensure the valves could not hit the piston. I've installed F, X, B and E cams with 1.6 and 1.7 ratio rockers and still have to see one with clearance issues after I've checked ...... YOU need to check in YOUR setup...... FWIW, my junk has the X-303 with 1.72 ratio rockers and 289 heads, that's .583" lift..... did I have to notch? ...but I checked and made sure clearance was not a problem.
01-28-2008, 10:46 AM
#23
5th Gear Member
Join Date: Oct 2005
Location: Ohio USA
Posts: 4,616
RE: GT 40 heads ?
Im looking at your modifications you have already and see great potential.
X303 should be run alone without 1.7 Roller Rockers with your setup. Unless you want a glob of upper torque, in exchange for reduced Horespower.
The other Letters, will be ok to use 1.7 Roller Rockers, but work fine alone.
You should lose the chip and have it reburned or dyno tune the car.
As far as the springs, they are upgraded springs and belong there. Ported makes power, and so
does COMBINATION.
This is not a stroker engine and you dont want all your power in RPM ranges, your not going to see.
Bullseye, 260 Flywheel Horsepower 320 Lbs Flywheel Torque without a tune @ 5,490 rpm.
With a tune, id say 270 and 325 @ 5,200 rpm
X303 should be run alone without 1.7 Roller Rockers with your setup. Unless you want a glob of upper torque, in exchange for reduced Horespower.
The other Letters, will be ok to use 1.7 Roller Rockers, but work fine alone.
You should lose the chip and have it reburned or dyno tune the car.
As far as the springs, they are upgraded springs and belong there. Ported makes power, and so
does COMBINATION.
This is not a stroker engine and you dont want all your power in RPM ranges, your not going to see.
Bullseye, 260 Flywheel Horsepower 320 Lbs Flywheel Torque without a tune @ 5,490 rpm.
With a tune, id say 270 and 325 @ 5,200 rpm
ORIGINAL: URLACHER54
ok i got a used set of GT40 heads that were rebuilt and have about 2000 miles on them, but the guy i got them from said i probably cant use the springs he has on there that they might be to high.so my question is what do i need to make these bolt on my car with no notching of the pistons or anything like that. what is the max spring size, what roller rockers (1.6 or 1.7) and what cam E303, X303, B303 etc. i do know i will be using the 93 Cobra intake and i have the heads and they have the studs for the rockers but i dont know what or how to change the springs too.
ok i got a used set of GT40 heads that were rebuilt and have about 2000 miles on them, but the guy i got them from said i probably cant use the springs he has on there that they might be to high.so my question is what do i need to make these bolt on my car with no notching of the pistons or anything like that. what is the max spring size, what roller rockers (1.6 or 1.7) and what cam E303, X303, B303 etc. i do know i will be using the 93 Cobra intake and i have the heads and they have the studs for the rockers but i dont know what or how to change the springs too.
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