Cam Questions

Unit 5302 · 05-16-2002, 06:36 PM

The GT40 P heads have a max lift rating of .500. Just like the factory E7TE heads. Nothing wrong with the springs, they just aren't designed for high lift, neither is the head.

The GT-40P heads drop in flow after .500. Which means if you have a .533 lift cam, you're pushing beyond max flow. The P heads flow nearly the same at .400 as they do at .500.

Take a midline XE series cam. XE266HR. .544/.555. That's more lift than: TFS TW, GT-40, GT-40P, Windsor Jrs, etc allow. It may not run into piston to valve clearance problems due to the XE cam having poor duration. About the duration causing issues with the newer computers. First off, this isn't a newer computer controlled car. We're talking pre SN95. Second, it's not the duration the cars have issues with, it's the LSA. Roller cams have obvious advantages in any lift situations, especially high lift because their design allows them to work with much less friction. Friction isn't what I'm getting at here. I'm getting at work. It's a crapload of work to run a camshaft. When my belt broke on my 2.3L LX and I cranked the engine over, that starter was at least 1 1/2 times as fast. That's how much load the valvetrain puts on a starter cranking 200rpms. The more you lift, the more power loss you're going to have. Friction doesn't really enter into the equation, and neither does the roller cam since all the cams suggested are of the roller variety.

Like I stated before, the HO cam is a proven performer too. That doesn't mean it's a great choice for a performance cam. The XE series may perform better than stock, but at the cost of upgrading hundreds of dollars onto the parts that she has chosen. On a budget, with GT40P heads, the XE cam is junk.

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Switch to Linear Mode Switch to Hybrid Mode Threaded Mode	Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Just got a 98, have some questions?	98GTNewbie	Modular Madness	5	08-30-2003 12:41 AM
Quick questions on Explorer Intake install.	Falcons Talon	Windsor Power	2	08-21-2003 12:40 PM
Several questions about oil.	zepherman	Windsor Power	3	08-03-2002 06:59 AM
HELP! Newbie 95-96 GT questions	Ron Brooks	Blue Oval Lounge	7	07-11-2001 07:38 PM
S/R Questions	DAMION	Racer's Club House	1	09-30-1999 11:02 AM

05-16-2002, 06:36 PM	#27
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	The GT40 P heads have a max lift rating of .500. Just like the factory E7TE heads. Nothing wrong with the springs, they just aren't designed for high lift, neither is the head. The GT-40P heads drop in flow after .500. Which means if you have a .533 lift cam, you're pushing beyond max flow. The P heads flow nearly the same at .400 as they do at .500. Take a midline XE series cam. XE266HR. .544/.555. That's more lift than: TFS TW, GT-40, GT-40P, Windsor Jrs, etc allow. It may not run into piston to valve clearance problems due to the XE cam having poor duration. About the duration causing issues with the newer computers. First off, this isn't a newer computer controlled car. We're talking pre SN95. Second, it's not the duration the cars have issues with, it's the LSA. Roller cams have obvious advantages in any lift situations, especially high lift because their design allows them to work with much less friction. Friction isn't what I'm getting at here. I'm getting at work. It's a crapload of work to run a camshaft. When my belt broke on my 2.3L LX and I cranked the engine over, that starter was at least 1 1/2 times as fast. That's how much load the valvetrain puts on a starter cranking 200rpms. The more you lift, the more power loss you're going to have. Friction doesn't really enter into the equation, and neither does the roller cam since all the cams suggested are of the roller variety. Like I stated before, the HO cam is a proven performer too. That doesn't mean it's a great choice for a performance cam. The XE series may perform better than stock, but at the cost of upgrading hundreds of dollars onto the parts that she has chosen. On a budget, with GT40P heads, the XE cam is junk.