liketoskate1

just woundering .....@ what performance level do the 165's become restricive to the motor 400-450hp maybe? I'm planning on stroking later to 347 and keeping it N/A so would the 165 be @ their limit, how about 185's? THX

WLingle92lx

The 165's are made for 302 engines in the idle-5500 rpm range. They have 1.94/ 1.60 valves which are good for the street cause they produce alot of torque.

The 185's are made for 331-347 strokers in the 1500-6500 rpm range. They have the larger 2.02/ 1.60 valves and larger 185cc intake runners which will take away torque but gain alot of horsepower. There even the same price as the 165's. The only needed to run the heads is notching the pistons for the larger valves.

The 165's are the same thing as the GT40X heads. I would just go ahead and get the 185's even with a 302. They work excellent! If you don't mind sacraficing torque for horsepower than they going to work!

The 165's are not worth it in the long run because they will be restictive at about 400-450 at the motor like you said.

I'm running a 306 with heads that have 247cc intake runners and 2.10/ 1.60 valves. They suprisingly produce alot of torque cause of the cannted valve design and produce SUPER top-end power. I was going to get the 185's but got these because I will never need to upgrade in the future.

Another thing to consider is the heads I have. There called Jon Kaase heads and there $1600.00 on Jeg's.
They Flow 331 CFM @800 lift. Thats more than AFR 225's and there $500.00 cheaper. KEEP THIS IN MIND!

Twister

just remember, bigger isn't always better....for a street car, I would look at 165's

tl86gt

165's would easily support a 500 hp N/A 347 IMO.... i wouldnt go 185's until you get the stroker. id wait and do it all at once.

WLingle92lx

That is very true! It takes the fun out of the "Street car"

When I was running my old 302 with a B303 cam and ported stock heads. When I would pull out and stomp on it........it would just light the tires up thru all of first gear.

Now With the Z303 cam and huge heads when I pull out and stomp on it...........it falls on it face till around 3000-3500 rpm when it throws you back in the seat like you got nailed by a train. Especially with the juice turned on

If you like to fool around on the street and light the tires up at low RPMs than get a good "TORQUEY" set-up.
For the street I would get the 165's. Like you said there only really restictive at around 400 motor Horsepower.

bouchermb

What about if you have a 5 psi SC? 165 or 185?

tl86gt

302,306,331,347? etc. for a FI motor id almost for sure go with the 185's.

bouchermb

302