Couple quick questions on roller rockers

[BobCarter]

What are the Stock Rockers on my 99? 1.6?

What would be the advantages/disadvantages to changing them out with 1.6 or 1.7 roller rockers?

Would it still idle normal and be a civil daily driver? I plan on keeping the stock cam.

Thanks!

 

[Turdle]

If you have a 5.0 v8 then the stock rockers are 1.6: 1
Going to 1.7 would increase valve lift and duration, but I don't know if the piston to valve clearance would be an issue. I would assume you'd be cutting it pretty close, as the stock pistons have valve reliefs cut in them, and that is for stock valvetrain spec,s.
Also, 2.02" valves won't clear pistins as they are

Intake lobe .2637" X 1.6 .422"
X1.7 .448" lift at valve

exhaust lobe .2801" X 1.6 .448"
X 1.7 .476" lift at valve
duration figures i don't know, but the valves will open sooner and close later, increasing the likelyhood of the piston and valve wanting to be in the same place at the same time

However, roller rockers themselves are pretty smooth operating, but I question if you,d really need them with the stock valvetrain, or notice the difference, since the pcm won't let engine rev above 5500 rpm's
anybody else ?

 

[BuzzisCrazy2]

What he said...........Don't waste you money , unless you are doing a Full build.

 

[Aussie Explorer]

Less friction, which in tern allows more power to be developed and that’s about it, but unless you combine it with other Pro-Formance stuff you will not notes much if anything.

 

[Green98XLT]

Actually going to a 1.7RR on a stock mustang is of measureable benefit. It usually shows slightly more HP and Torque. Of course you always have to measure for coil bind with the valve springs and check piston to valve clearance to be sure, as all motors are not alike.

The Ex 5.0 has the GT40 P heads on them which actually have smaller valves than your typical mustang head. As long as you check the important stuff I'd go for it! 1.7's worked really well on my 95 stang back when it was stock.

 

[slo5o]

gt40p's have really weak valvesprings from the get go, I dont think 1.7's would be wise to run on stock springs. Unless you have low miles on the motor go with the 1.6's (stock ratio). Also I pretty sure they wont clear stock valve covers, the mustang's valve covers are taller and you have to clearance them for roller rockers. If you do go with the 1.7's the valve clearance will be fine, I personally have run the trickflow stage one cam in a stock 98 explorer motor with no problems. .499/.510 lift, 221/225 @ .050 but I did upgrade the springs and used mustang style valve covers.

 

[Green98XLT]

Good point about the valve covers... I forgot the Ex got a different set of VC's than the stang motors did.

I ran an F303 cam on a set of stock P heads years ago just to get my car going until I had the time to put the good springs in, it worked fine just kept the revs low.