Mustang_NTriangle

I am getting ready to install my blower cams and Beehive springs but concerned that stock valves won't hold up to my HP goal and high rpms.

Does anyone know what stock valves and retainers can properly support or how has actually run stock heads with FI w/13 psi on a 9.5:1 compression.

I was looking at MMR valves (stock size) along with bronze retainers.

Frostbitten

the valves are fine. you should have ordered better retainers along with the new springs

SVTeeshirt

what frost said, i think you should be okay at 500 but you might wanna play it safe.

Mustang_NTriangle

Are u using stock valves and how much power you making with your car? Do you put your car in high rpms often?

99BlackPonyGT

i wouldnt risk it...you got too much money in your car to risk ****ing it over some cheap valve locks...just watched my buddy grenadehis LT4 after 100 miles because it dropped a valve using stock ****

nickmckinney

No problem running stock valves, retainers, keepers, etc to 500RWHP. Only thing really needed to be changed are the valve springs as long as you have enough piston to valve clearance on the intake. The stock valves in these motors are actually really strong and their only problem is the big lip on the end kills the piston to valve clearance.

We have a turbo car making 700ftlbs to the rear tires for the last 2 years with the stock retainers and keepers, and EV8 valves with Comp high load springs. Only time I recommend a retainer change is if you are going to hit 7000RPM on a regular basis as the aftermarket retainers are a bit wider and match the springs better.

GrayGhost01GT

Im like the guys above I woulden't Risk it you might be okay for the first couple thousand miles, but if you really start to run her you could run into some problems I would just get the retainers done! Just my 2 cents

Mustang_NTriangle

If I do purchase new valves (stock) I will have to seat them by machining them. What are the chances of this creating more problems i.e. tolerance extra. I won't be doing them by friend who is a Ford Tech will be doing the work but I am just trying to under my risk.

I will be spinning her pretty high (i love acceleration and 4.10s

How are these retainers Comp Cams Valve Spring Steel Retainers (96-04 4.6L 2V)?

http://www.americanmuscle.com/mustan...tainer-2v.html

Frostbitten

those are the n/a retainers. comp makes a "high load" version which is for boosted cars. im running manley nextek valvesprings and comp high load retainers. just take the heads to a good machine shop and have them do a valvejob on it. I took mine in and they found 2 bent valves so i got new ones put in. They installed the springs and did a valvejob on them only cost me like $100. The car runs great. whenever im getting into boost i normally dont take it past 6000rpm. my tuner has my rev limiter set at 6500, but in reality the parts are good for 7000+rpm...

nickmckinney

+1 - a good performance valve job is probably worth 5-10CFM on these heads.