OnyxCobra

Boss, if u use heads that are too large, it will kill your performance. Thats why on 5.0s usually the AFR 165s will produce more power than the 185s. Hell, i plan on running boost on my 165s until i redo my bottom end eventually, I personally think 185s are better for the 331-351 cubic inch range. AFR told me it's fine to boost a 302 with 165 heads. An engine sucking its own air is a lot different than having it rammed in, so on larger n/a engines bigger valves and ports are needed, but on smaller engines it just chokes itself...

boss429

yeah, it just doesnt seem to make sense to me,

if an engine has all the air it want, and then some,

it should make its optimum power availible.

but whatever lol, ill ask my dad tomorrow, havent asked him something he couldnt answer yet

im going with 185's but im also gonna be running the 9psi hellion kit.

can't wait until the end of august

AdderMk2

Rockers are measured in ratio form. The actual lift measurments of a cam rarely are larger than .3xx lift. a rocker arm actually increases the lift by acting like a lever. The rocker itself will pivot on the center area that rest on the stud or pedastal. Take a ruler (this is for visual effect only) and rest it on top of a pen at the 6" mark. this is a 1:1 ratio and you have limited amounts of motion on each end. so now to increase the travel on one end of the rocker(or ruler in this visual) you would need to increase the length of one end. slide the pen to the 4.5" mark. this is approximately a 1.7:1 ratio. You can now notice the increased travel of the longer end of te ruler.... Lemme know if you want to know more.. i'll PM you

I haven't got the slightest clue what the LSA is, however i bet someone who knows more about cams could figure it out from those numbers.
But yea anyway... if .530 is the max you can go intake on a stock 5.0... then this bitch should fit. just make sure you get some REALLY heavy valve springs.. haha

Grabbem, I understand you have a 306 right now and are only putting down slightly over 300 to the wheels. I watched a 95 gt with Twisted wedge heads, Edlebrock PERFORMER intake, and a custom cam... make 336@the rear wheels. after a little bit of fuel tuning they got 341. So in my opinion.. yes, you wasted your time buying the 185cc heads... THAT IS OFCOURSE IF you don't boost the motor. Toss some boost on there and you will see better results due to increased flow.

AdderMk2

This is where we come into the port velocity VS port flow issue.
You need to keep consistant port velocity so the air will actually make it INTO the motor. If you look around on the internet for long enough you will find that people who run big turbo or supercharger kits usually run large port heads and box style intakes. This is due to the fact that the air is being FORCED into the motor. Port Velocity is no longer an issue in this case, however on a N/A car, too much is NOT a good thing.

Imagine taking a 10" piece of PVC pipe and laying down on the ground, and lay a 10" piece of garden hose next to it. The PVC pipe will flow a greater amount of air/liquid.. whatever.. BUT since there is so much room, the same amount of flow that would go through the garden hose can be accomplished by slowing down the flow, and that is what happens. the flow velocity is decreased and when you have a small window of time to fill a space (i.e. the cylinder) you will find that LESS air will actually make it into the cylinders, and also the fuel will be less atomized in the cylinder causing a bad burn, poor power, and a ****ty running car.

chath_brick

thanks adder, that helps a lot!

gspfunk

You should research the rpm range for the parts you plan on using.... the RPM2 is similar in range to the Track heat, which is 2500-6500. If you want tq, you need to be looking at the RPM, Street Heat, SSI, or Performer. You'll also want a cam that operates on that same powerband like the E cam or TFS stage 1. You need to match your parts if you know that's how you will be driving it. If you wanted a higher revving motor, the Track Heat or RPM2 and a diff cam would be of greater benefit, but you lose low end tq.

Also, I'm running 1.72's w/ my E cam on a stock bottom end w/ no problems [~.535 lift]. I went w/ the Crane valve spring kit; good to .550 lift. that's all on worked over E7's, BTW.....

boss429

yeah, that makes a lot of sense when put that way.

my car aint stayin N/A for long though, so im thinking 185's.

what would a good "box style" intake be?

if thats what i should be using for a turbo?

chath_brick

good point...i asked about the SSI before and some people told me to stay away from it, what do you think? will it give me better torque than the RPM II?

gspfunk

I like the SSI, but have no personal experience w/ it. All the people that have it seem to like it, but it depends on your plans as far as mods go. It will probably have more low end tq, but it won't be much more.

People warn you to stay away from it b/c they either don't like how it looks, or they don't know much about it b/c it's new. It will do well in the rpm range described above (up to 5500), but not past that.

chath_brick

lol the thing that first got me interested in it was the way it looked. i might go with that then, but i'm still a little way off from doing it so i have some time to decide.