stock gt40 valve train w/ trickflow stage 1 cam?
02-15-2008, 02:00 PM
#11
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RE: stock gt40 valve train w/ trickflow stage 1 cam?
ORIGINAL: golden_eye
Not entirely true. Cobras didn't come with an E-cam, but they did have a slightly beefier cam than the stock 5.0s.
Cobra's had a lift of 0.4797 whereas GTs are 0.442. If a Cobra had a stock cam the lift would be 0.4726 with 1.7 rockers. Doesn't sound like much but when half an inch is pretty decent lift (as far as what I have seen on average street cams)those fractions make a difference. I'm not too sure on the duration and other specs though.
ORIGINAL: my77stang
no, it was a stock cam with 1.7 rollers
no, it was a stock cam with 1.7 rollers
Cobra's had a lift of 0.4797 whereas GTs are 0.442. If a Cobra had a stock cam the lift would be 0.4726 with 1.7 rockers. Doesn't sound like much but when half an inch is pretty decent lift (as far as what I have seen on average street cams)those fractions make a difference. I'm not too sure on the duration and other specs though.
the cobra did NOT have a stock 5.0 cam... but it sure as **** wasnt an E cam
02-15-2008, 08:15 PM
#12
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Join Date: Mar 2007
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Posts: 636
RE: stock gt40 valve train w/ trickflow stage 1 cam?
If you put those 1.7 ratio rockers with the tfs stage 1 cam I think the exhuast valve is going to hit the piston! So you going to have to grind down the piston so it doesnt hit and while the heads are off you can get some valve springs good for .550 lift and stick them in.Then you will be good to go.Your going to have to change those springs if you use that cam anyway!
If you choose to go with 1.6 ratio rockers that cam will work with new valve springs of course..
If you choose to go with 1.6 ratio rockers that cam will work with new valve springs of course..
02-15-2008, 09:44 PM
#13
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RE: stock gt40 valve train w/ trickflow stage 1 cam?
O.K. I am working on the same thing and here is what I found out:
Spring pressure on GT40 factory springs-my heads have 50k miles on them and they only had 70 pounds of pressure at 1.75 install height.
I am running a B303 cam with the 1.7 roller rockers which equals 510 lift total. This is a combo the some here on this forum are running with stock pistons and no interference. I called Ford Racing tech line and they said it would be close but fine.
With the B cam and 1.7's, it was suggested that I need some where near 100 pounds of spring pressure.
Solution is:
Crane Part number 44308-1
or
Trick Flow part number TFS-2500100
This is what I have found out and hope it helps.
Spring pressure on GT40 factory springs-my heads have 50k miles on them and they only had 70 pounds of pressure at 1.75 install height.
I am running a B303 cam with the 1.7 roller rockers which equals 510 lift total. This is a combo the some here on this forum are running with stock pistons and no interference. I called Ford Racing tech line and they said it would be close but fine.
With the B cam and 1.7's, it was suggested that I need some where near 100 pounds of spring pressure.
Solution is:
Crane Part number 44308-1
or
Trick Flow part number TFS-2500100
This is what I have found out and hope it helps.
02-15-2008, 09:55 PM
#14
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Join Date: Jan 2006
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RE: stock gt40 valve train w/ trickflow stage 1 cam?
Cobra setup = Tbird-Cougar 5.0 cam w/1.7 rockers = .282" lobe lift (1.70) = .4794" lift and 270/270 adv. duration.
If the Stg 1 clears with 1.6 rockers (after checking, of course), it should also clear with 1.7 rockers.
If the Stg 1 clears with 1.6 rockers (after checking, of course), it should also clear with 1.7 rockers.
02-15-2008, 10:45 PM
#15
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Location: earleville md
Posts: 10,357
RE: stock gt40 valve train w/ trickflow stage 1 cam?
1st off, total lift has nothing to do w. ptv... check it, thats that.
and thats some low *** seat pressure.... i have .512 lift and my spring pressures are 120closed, and 310 open
anyway, w. gt40 heads, either find a single spring set up thatll have the appropriate rate, or have a machine shop cut the heads for dual springs
since you havent ordered shti yet, let me suggest 7deg locks and retainers, not 10 deg... their lighter, which is a good thing
and thats some low *** seat pressure.... i have .512 lift and my spring pressures are 120closed, and 310 open
anyway, w. gt40 heads, either find a single spring set up thatll have the appropriate rate, or have a machine shop cut the heads for dual springs
since you havent ordered shti yet, let me suggest 7deg locks and retainers, not 10 deg... their lighter, which is a good thing
02-16-2008, 07:00 AM
#16
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Join Date: Jun 2007
Location: Roseville, CA
Posts: 444
RE: stock gt40 valve train w/ trickflow stage 1 cam?
actually, i have everything, and the heads already have dual springs. im thinking the guy i got the cobra stuff from was already running a cam with beefier springs, and thats what force fed performance thinks as well. the springs are completely different than the stock gt springs in my old e7s. Ill keep yall posted as to what he finds while installing the cam.
02-16-2008, 10:12 AM
#17
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Location: earleville md
Posts: 10,357
RE: stock gt40 valve train w/ trickflow stage 1 cam?
their dual springs w. that low pressure?
are you sure their not single springs w. a dampner?
either way it looks like ur going to need new springs, locks, and retainers
a pic would be great
are you sure their not single springs w. a dampner?
either way it looks like ur going to need new springs, locks, and retainers
a pic would be great
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