Joel5.0

Again....don't measure how big a cam is by the valve lift....valve lift is not a problem with PtV issues...it's the OVERLAP. Here's an example....

Although the bottom one has a smaller lift, it's the biggest of the two.... Comp's has an advertised overlap of 47° and -4° @.050", and Crower's has an advertised overlap of 85° and 19° @.050" = even though the Crower has less lift, it will have PtV clearance issues....if the valves clear with a 1.6 rocker, they should clear with 1.7's. You would have to check clearance issues at the rocker-retainers/springs though....and OEM valve springs are only good for the stock cam, if you plan in upgrading the cam with a lift over .470"...the springs could bind. My 2¢.

FullAuto

I think you're getting confused between the spring rating and what will actually fit. Just because the TFS Track Heat has .600 lift springs does not mean you're going to get anywhere close to getting that .600 lift cam to clear that stock shortblock. So that's just a spring rating. And if you change the springs, sky's the limit. For example, I have a .771 lift cam for a set of TFS TW.

I'm with Joel on this one. It's all about cam timing. But without seeing all that information in most catalogs you're looking at, a good rule of thumb would be .540 or less and 224* @ .050 on the intake side or less. This should keep most people out of trouble.

FWIW, I've ran a .545/.545 cam on a stock shortblock with stock heads, but it was a custom grind cam.

Ninety5five0

The P heads i got do have upgraded springs on them already.
Does the intake and exhaust duration change ? Or is that always the same no matter what rockers ?

Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,000-5,500 RPM
Intake Duration at 050 inch Lift: 221
Exhaust Duration at 050 inch Lift: 225
Duration at 050 inch Lift: 221 int./225 exh.
Advertised Intake Duration: 275
Advertised Exhaust Duration: 279
Advertised Duration: 275 int./279 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.499 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510 in.
Valve Lift with Factory Rocker Arm Ratio: 0.499 int./0.510 exh. lift
Lobe Separation (degrees): 112

I think i am confused on a few things here. Another reason was, i am finding alot more 1.7's for cheaper.

Ninety5five0

Also, those P heads require a pedestal mount rocker. I can get a conversion kit right ? That makes it from pedestal to stud so i can use a stud mount rocker ?

aode08

its the duration where u run into issues and again, stick with the 1.6 rollers, with any aftermarket cam. .224 .225 @ .050 IS A VERY COMFORTABLE DURATION with the ECM with idle.

the bigger the cam, the more your powerband gets shoved UPWARDS and our 5.0's dont like going past 6000 rpm, so stay with a stage one or stage two. A stroker motor with deep valve reliefs is different, you can go with higer duration cams (BIG CAMS).

2.Ive seen non - stroker engines, LOSE OVER 29 HP , having a big cam, like my buddy jim, he ran a trick flow stage 1, cam with his AFR, 165'S AND 1.7 ROLLERS WHICH ADDED MORE DURATION AND LIFT, then told me his car is not powerfull as he thought and all the power is in first gear. Since we didnt feel like removing the cam, I told him to sell his 1.7's and Id instal the 1.6s and set the lash for him for $100. After that, the car hauled azz ! first , second and third gears.



3. valve size. 2.02 intake valves dont clear the stock pistons, INSTAL TWO THIN SPRINGS from home depot in favor of your normal ones ,a dab of white paint on the valve, with OLD headgasket installed, and valve lash set (one head needed and two head bolts,ONE CYLINDER, BOTH VALVES ADJUSTED) youll see the interference. They need a wider and upper path. So grind them one on each piston.


4. OTHER Options: you can get head shims that add .040 .060 .080 etc additional clearance from the head to the block. It lowers the compression ratio just a little,. I favor them, for advanced timing without pinging and nitrous or blower.

XSRACINGGT

ok, heres my two cents worth..... I installed a set of 1.6 SVO/FRPP Roller Rockers,TFS Track Heat heads, (.600 lift springs) on a stockblock 87 GT. I put in a TFS stage two cam. 0.286 advertised duration( .236 at 0.50). When installing it straight up, I had only .040 maybre .060 between the piston and the valves at tdc. Trick Flow has rotated intake valves that allow you to run a 2.02 intake valve on stock blocks/pistons(with valve reliefs) with no clearance issues. I didn't like how close my pistons were comming to the valves, so I retarded the cam 4*. theat made it have 0.115 clearance. All those clearances were taken with NO head gasket by the way, only the heads were on the block. Retarding the cam makes the powerband move upwards 100 RPM every 1* of retardation. so my cam has range from 2900 to 6400 instead of 2500 to 6000.

My timing issues.....I know i said in another thread I wasn't happy with the combo and some of you told me to check my timing and such. I wasn't making ANY power below 3500 rpms. I checked it over again and I was running 0* base timing!! I moved it to 10* and Holy ****! its so fast! I love it. THANKS TO ALL THOSE WHO HELPED ME!!!

SO..in conclusion. What I am trying to say is that certain combos and installation methods will allow you to run a bigger cam. but, A bigger cam on a stock piston, block engine will probably not be benifical to you in power making combos. stay with something less than an X cam, unless you want to retard your cam. That will make you have thebest power capabilities on your mild H/C/I 5.0s.

As for AODE06,Fullaoto, Joel, and 89gtsleeper, I agree fully with what you said. I have seen guys install too big of cam and it either kill their car, or crash pistons in to the valves. CHECK YOUR CLEARANCES!! and bigger is not always better. beleive me I've seen it to verify it! thanks guys.

aode08

my wife disagrees