bone stock 5.0... adding 1.7s require sping upgrade???

[Foxfan88]

i had some people tell me that i would need to. but it wouldnt raise the lift that much. then my friend had the rockers that i have now, he put them on it stock motor and said it ran good.....
so??

 

[Mike92GT]

I had 1.72 rockers on mine for a long time when I still had stock heads, and I never had any problems. However the stock valve springs are known for being weak, and there is the possibility that the increased lift can cause valve float at high RPM, especially if your springs have high milage

 

[2000xp8]

No, you shoudln't need springs, but make sure you have a shim kit available at the time of install.

 

[Foxfan88]

this may sound gay but what is the shim kit for??

 

[Curse]

I actually shied away from 1.7 rockers because a lot of people told me I would need a spring change. It was not worth it to me.

 

[soontobefastfox]

I wouldn't do it, you'll actually lose power.

http://www.fordmuscle.com/archives/2001/10/rockerarms/

 

[yelladawg351]

From my understanding looking at tech issues on 5.0 Mustangs the stock E7TE heads can handle .500 lift pressure from a cam. A stock 5.0 cam is around .444 lift @ .050. Just keep your RPM's around 5200 and 5700 to prevent valve float. I believe it would put a stock cam around .456 lift. Look around this forum to find the formula for caculating the added rocker lift to a cam. Crane makes a good set for that comes(1.7 ratio) with shims, but you might not need them on your stock head but just read the instr. Yelladawg.

 

[Modular2v]

the stock springs can handle 500 lift....im running a 498/499 lift cam

 

[tmoss]

Fresh stock springs or 150,000+ mile springs - BIG difference!

 

[Euphoric306]

plus you're running the b cam right? id definitely wait it out foxfan and get all new springs, hardened pushrods, rocker arms, shimkits, and just upgrade your heads all at once. or wait on the head upgrade and get a cheap intake, wait till you get some gt-40's or other budget performance heads, dont go throwing a bunch of good parts into worn out unported e7's

 

[04sleeper]

Fresh stock springs or 150,000+ mile springs - BIG difference!

I have seen 70,000 mile springs turn to mush in just a few weeks with 1.72's

 

[QDRHRSE]

Unless your stock springs are pretty new you will have a problem. TMoss put it best.

 

[88gt]

If I recall, he's already done this....he's asking after the fact...

 

[Euphoric306]

If I recall, he's already done this....he's asking after the fact...

again

 

[troyGT03]

i didnt see e-cam in his sig. tmoss said it right on springs. but good low mileage motor, 1.7s wouldnt do anything but lower the valve float rpm if the spings are not up to par. good healthy low mileage motor no prob. i just did it on mine. 67k and never beaten on.

 

[18mustangs]

Dont' take the chance, just get the new springs if you're planning on running 1.7s. I hear that valves crashing into pistons is a significant emotional event that you could do without.
Tim

 

[Mustang5L5]

I would change them. Trick FLow makes a nice kit for the stock E7's for about $150

 

[89'5.0]

If you have the capability i would change the cam to a f-303 and upgrade and use the ford motorsports spring upgrade. This combo works outstanding. Though if you can't do a cam swap and want to use the 1.7 i would change the springs just for the sake of valve float.