crueheadstang87

Iam thinking about buying AFR 165cc heads ,Holley Systemex 2 Intake, and f303 cam, Do you know if i will have any piston and valve clearance problems with this setup, i will be using stock pistons, and do you think this is a goood combinaation? thanks for your imputs


Justin

mjr46

nope I have a f-303 in my 92 with stock heads and stock pistons and no ptv issues

5spd GT

AFR 165cc have different size valves than stock heads. The radial is going to be different, although the valve angle is the same at 20*. Hard to compare...

1.90" vs. 1.78" on the intake side.

1.60" vs. 1.45" on the exhaust side.

Advancing the timing opens the intake sooner and closes the exhaust sooner. That will gain you some clearance on the exhaust valve, but you will lose clearance on the intake valve. Retarding the cam causes the timing to open the intake valve later, and closes the exhaust later. You'll gain clearance on the intake, and lose clearance on the exhaust. So changing the cam timing won't result in increasing clearance on both valves.

By changing the position of the camshaft, it will change how it performs. Keep this in mind...

You need to see which one you need most...

Adjusting either way can shift the powerband +/- 200 rpm that direction...

The general rule of thumb is .080" on the intake side, and .100" on the exhaust side. A few manufacturers recommend .100" on the intake side, and .125" on the exhaust side.

The exhaust side needs a little more clearance due to a couple reasons:

- Piston chasing the exhaust valve as it is closing (spring has less control).
- Heat expansion
- Chain stretch (retards the camshaft)

Good Luck.

mjr46

It's not gonna hit no worry...i SOLD MY FRIEND a 89 roller block with an f-cam in it and stock pistons and eddy rpm heads with yes and I repeat yes the 1.90/1.60 valves and that motor has over 300 passes at the track so trust me not gonna hit.. but check ptv to be safe

PJC Racing

Either way, If you went with a Twist Wedge head there would be no issues.

cruiser

I AGREE

WhiteWindsor

I like your way of thinking.

302army187

how is the f-303 cam?

anyone wanna tell me how they like it?

im looking for a streetable cam, when i do my heads, that has a nice lope sound to it

stang8689

If your buying a new cam i would check options cause Ford cams are 1 stage meaning exhaust and intake are the same. Many companys like Comp, and Steeda have dual stage with different exhaust and intake duration. Alot of people with Ford cames use 1.6 rr on intake and 1.7rr on exhaust. Just a thought

302army187

very good point.

i have to decide on alot of things, im trying to get it all together as soon i will be gathering parts


ill prob just start my own "help me decide parts" kinda deal