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Topic: GT40P/Aftermarket valve springs (Read 1475 times) previous topic - next topic

GT40P/Aftermarket valve springs

Hey guys, been doing some reading online about the HO swap and precautions before doing so (I have no previous knowledge in this kind of stuff, so bear with me). 
I am planning on installing the GT40P heads in my bird.  I've read that the stock valve springs on the GT40Ps are trash, and that I should buy aftermarket.  People say the Trickflow kit is a good buy, but they can also act up.  Others mentioned the Alex parts springs that are a great buy and good for the price, and also Crane cams have a reliable set.  Someone lead me in the right direction..

In addition to that, is there a way to avoid the spark plug clearance issue when you use stock mustang headers with the GT40Ps? (smaller spark plugs, different boot, i dunno, etc).  Thanks guys.
'88 Thunderbird LX
[SIGPIC][/SIGPIC]
Engine:  FR B303 cam, GT40P heads w/ Trickflow valve springs, Explorer upper/lower intake, SR cold air intake w/ MAF
Exhaust:  shorty headers, BBK O-R X-pipe, glasspacks w/ turn downs
Misc:  8.8 rear, Saleen SC replicas 17x8/17x10, Mach 1 front springs/SN95 rear springs
&
'74 F100 Custom 351W

GT40P/Aftermarket valve springs

Reply #1 –
Ford Racing makes Mustang (or other Fox platform) swap headers just for P heads.  You can also run shorty plugs, but the ones that fit P heads are expensive.  For my P heads, I just sent them to my machine shop and told them to hook me up with springs and retainers to suit the cam I picked.

GT40P/Aftermarket valve springs

Reply #2 –
Quote from: TheFoeYouKnow;437840
Ford Racing makes Mustang (or other Fox platform) swap headers just for P heads.  You can also run shorty plugs, but the ones that fit P heads are expensive.  For my P heads, I just sent them to my machine shop and told them to hook me up with springs and retainers to suit the cam I picked.

Thanks for the info!  Do standard brands like NGK and Accel sell shorty plugs?
'88 Thunderbird LX
[SIGPIC][/SIGPIC]
Engine:  FR B303 cam, GT40P heads w/ Trickflow valve springs, Explorer upper/lower intake, SR cold air intake w/ MAF
Exhaust:  shorty headers, BBK O-R X-pipe, glasspacks w/ turn downs
Misc:  8.8 rear, Saleen SC replicas 17x8/17x10, Mach 1 front springs/SN95 rear springs
&
'74 F100 Custom 351W

GT40P/Aftermarket valve springs

Reply #3 –
Quote from: TheFoeYouKnow;437840
Ford Racing makes Mustang (or other Fox platform) swap headers just for P heads.  You can also run shorty plugs, but the ones that fit P heads are expensive.  For my P heads, I just sent them to my machine shop and told them to hook me up with springs and retainers to suit the cam I picked.

I used (and still use) FRPP GT40P headers when I ran GT40P heads. As far as springs I used the springs Comp recommended with my cam. The machine shop made the Comp springs fit.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

GT40P/Aftermarket valve springs

Reply #4 –
I have heard good things about the Comp and Twisted Wedge springs both.  If you have a good machinist (read shop that builds engines with an in house machine shop) local to you then they can set the heads up to the cam you pick.  With the GT40 and GT40P heads being pedestal mount type I would think that they would be limited to how aggressive you can get with open/close pressure on the springs.

As far as headers go for the GT40P heads a lot of the guys running these heads (including the Mustang crowd) run the BBK 1515 unequal length shorty headers and report that the #7 plug is the difficult one to access.  One guy suggests the following:

[COLOR="#0000FF"]I use the bbk headers with p heads, you only need a 90* plug on the #7 cylinder. To change the plugs on the # 7 you can cut about a 1/2" off of a spark plug socket. then cut a narrow slice down the middle of the socket so it will slip over the end of the plug. the slice doesn't have to extend all the way down the plug, just enough for the plug to be able to slide through. then you can use use a open end wrench to tighten or loosen the plug. the rest of the plugs you can get in and out with a standard spark plug socket and open end wrench. you will definitely need boot protectors.[/COLOR]

Darren

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp
 

GT40P/Aftermarket valve springs

Reply #5 –
Quote from: Aerocoupe;437859
As far as headers go for the GT40P heads a lot of the guys running these heads (including the Mustang crowd) run the BBK 1515 unequal length shorty headers and report that the #7 plug is the difficult one to access.  One guy suggests the following:

I use the bbk headers with p heads, you only need a 90* plug on the #7 cylinder. To change the plugs on the # 7 you can cut about a 1/2" off of a spark plug socket. then cut a narrow slice down the middle of the socket so it will slip over the end of the plug. the slice doesn't have to extend all the way down the plug, just enough for the plug to be able to slide through. then you can use use a open end wrench to tighten or loosen the plug. the rest of the plugs you can get in and out with a standard spark plug socket and open end wrench. you will definitely need boot protectors.

Darren
And you had better believe it.  My BBK's work, but when I had to pull #7, I took the header off.