Im building a mild 350, with comp xe268 cam and kit, carbed with 650 cfm, headers, stock bottom end, what heads would be a better choice, i have a stock set of 081 305 heads that have been ported, or should i go with the vortec heads, the iron ones, also the car will be daily driven and the pistons are dished and have valve reliefs. I may go ahead and get soem flat top hypreutic ones.

thanks for any info

Kevin

 

The ported 305 heads will be less expensive and produce about the same power. However, you MUST cut down the spring seats to accomodate a cam with that much lift, and use better springs. Also, open the intake valves out to 1.94".

 

The cam is too big for "mild" and the dished pistons.

Either head can work well. (with mods)

If I were to go with the 081 heads I'd port them more and install 1.94x 1.60valves.. This can/will get them up to the power level of the vortecs.

Don't be shy. They need a good bit of porting.

get the book "How to build Chevy Small Blocks on a Budget"

It will show you what to do to the heads. Just pretend they are the "186" camelbacks or Corvette L-98's in the book descriptions
on head preperation.

The 268XE will need the extra compression of the flat tops pistons. It will also favour a high stall converter and high rear gears.
If you want a "mild" motor build it with good head flow and velocity and "mild cam timing" Keep intake .050" duration at 218 or less.

Of course the vortecs will work very well too. (with the proper valvetrain mods)

 

so do you all think i should go with the xe262 or the 268, with stock converter or corvette stall, and 3.42 rear. Thats why i was gonna use the 305 heads to keep compression up.

 

Absolutely.......

The 268XE is soft on low end torque.
really needs a 3000 stall and more gear.
the XE 262 will make a better "daily driver" cam.

I would go with a 214/224 on 112 cam, myself.
use 1.6 rockers to get extra lift. this cam with good heads pulls nicely to 5500 rpm.

It all depends on what you call a daily driver and how important
drivability/ mileage is, to you.

Get the bigger valves and fully-port the 305 heads.

 

Check my sig. I have the xe268 and vortec heads. On the track times the 1/4 mile time is with 100 hp shot and no traction and the 1/8 mile time is with great traction and 125 hp shot. I vote vortecs for your setup.

 

Sorry, I forgot to put my sig on. Here it is.

 

The Vortec heads have superior design over the 305 heads. I don't know where you guys get your info but theres no way the 305 heads flow anywhere near what the Vortecs do.

It will cost you for new valve seals and to have the spring pockets machined down, but in the end they are the best heads out there for the price.

 

Believe it or not, that is not what we said. He has PORTED 305 heads, and when you do them right they will flow BETTER than Vortecs.

 

Iroc: I more than agree with ya that the vortec are the best *New* head out there for the $Bucks$.

I have 2 sets. I also have ported quite a few of the 305 heads with bigger 1.94 x1.60 valves and they do indeed out flow
the stock vortecs. This is flowbench verified.

Have been working on a special combination radius angle cutter tooling that really puts a cool radius in the bowl area.
Going to try this on the 305 heads and the vortecs.
Should result in a higher volocity and flow at low and mid lifts.
reduces the porting time and decreases the port to port variance.

I'll post the results.

 

I had the radius valve job and backcut done to my vortecs about a year ago. I never had them flowed though.

 

I'd go with the vortecs every time.

The time and effort into a set of 305 heads doesn't seem worth it to me, when the vortecs still have a superior chamber.

I'd use the vortecs, and since it's a daily go faily conservative on the cam, something on the line of the XE256 cam. the car would have very good manners and wouldn't need a lot of converter or gear, andwould have some good power.

Flownumbers aren't everything.

Even at that the vortec start off much better, require much less work.... they are just a better head.
those heads, performer rpm intake, 1.5 rockers. and that cam would be a reiliable street performer.