Well i pulled apart the 305 in the LG4 camaro i bought not too long ago.

The heads turned out to be 14014416 (416s) and i plan on porting the hell out of these now.

Anyways ive pretty much wore out the search feature trying to find a definative answer as to what the max lift is on these heads. I plan on running comps XE268 which will give me .48" @ the valve on 1.5 rockers.

According to DDs bull this motor should be making 480hp/470ftlb which should make for an interesting daily driver

 

DAMN! That does give me hope!
I heard .460" is about the safe limit, but due to production tolerances, you should be using a caliper and checking anyway. You'll most likely have to mill down the valve guides (or use .050" offset retainers). Since you'll probably go with machining the guides, then you can use positive valve seals. (or use the fel-pro ones that fit on stock guides, and use offset retainers... your call).


Do you have a die grinder yet? also, if you have a drill press of relative quality, you can probably do the guide boss machining at home (since i'm guessing you're still against the shipping to a machine shop?)

PS. make sure you check your valve guide quality, ie, have a valve sticking ~.5" off the seat, and caliper the play when trying to "wiggle" the head of the valve back and forth. I think something like .005" is ok...
The valves themselves should be ok with as little as .001" wear on the shank.
If you HAVE to send them out to be machined, might as well get it all done at once.

 

480 HP with an XE268 would require about 430 cubic inches.

As Sonix said, cut down the guides, measure the resulting travel with the stem seals installed and after the valves/seats have been ground. More than likely you won't have any problems with the .480" lift.

My Worlds are good for about .550" lift with standard valves & retainers, and positive stem seals. 416's should be similar when done as described.

What are you planning on doing with the rocker studs?

 

oh yea, going to mention that.
since you're going for a cheap build up (right?) probably don't want guide plates and hex collared studs? standard replacement thread in studs? (mr gasket non collared?) or good 'ol pinned?
ps. I have 498 roll pins for this, waiting to be thrown out, if you want them.

 

Havent thought a whole lot on what ill do with the studs but i probably will end up just pinning them.

I have both air and electric die grinders, i will probably do it with the air one though. i do also have a drill press so i can do the guides here if need be.


How do you figure it wont make 480hp? both dd2000 and dd2005 are showing me similar numbers with my setup...

 

If you lie to Desk top dyno, it will lie right back at you.

The only way your going to make 480 horses with 416 heads and a XE268 cam is to bolt on a 6-71 blower and crank the boost.

Get real..... If you were to fully port these heads with larger valves you'd be doing a very good job if you got 370-390 horsepower with that cam.

If you want over 400hp you will need a big-big solid lifter cam and a vic JR with a 750-850cfm carb.

Re: desk top dyno*
Use seat duration 268-280 in the cam timing section, not .050"
Much more accurate
Those heads will flow in the 230cfm range when *fully home ported with big valves*. Select the "pocket ported" choice to model them.

The fully ported selection over models these heads making the power look too good.
It refers to porting a Hi-performacne head like a Camel back or simular to start with which will port out to 250-260cfm.

To get 250-260cfm from a 416 head requires lots of epoxy or port welding and reshaping. (extensive professional porting$$$)

But you'll get good performacne at 230cfm but not 480hp.

Further in DDyno the induction system airflow choice means the total amount of airflow that the engine is consuming at WOT. Not the carb flow rating.
Enter about 550+/-cfm.
This is the airflow reading that you get on a engine dyno test readout. It give an accurate indication of the actual volumetric efficiency of the motor. if you enter 750cfm even thou you have a 750cfm carb, the power will be over stated. Typical engines like this one as built with the parts you chose will consume about 550cfm+/-.

A carb is rated at 1.5" vacuum.

At maximum rpm power output this engine would show about .75"-1" on a vacuum guage, not 1.5".

I get a an honest 391 HP@6000 and 410Ft/lbs @4000 at 10:1 compression with a dual plane manifold. from DDyno

Desk top dyno is very accurate *if* you understand the selections and model the choices correctly and realisticly.

Then it becomes a powerful tool.

390 crank hp is enough for high 12's. (proper rear gearing and converter stall , open headers and slicks)

 

For flow numbers i did some searching here and used the numbers that people here have gotten from home porting jobs. So the numbers there arent too much out to lunch.

Max flow was 217intk/159exh for the ported 416s i used.

For the carb i used the 750cfm holley double pumper. RPM air gap manifold. xe268. 1.5rr. 10.5:1cr, 93oct, HEI 8-36* adv. and open headers just like i run.

This is what i get, maybe its on crack....
479HP @ 5800RPM ve100%
472ft/lb @ 4500RPM ve93%

 

ok, i think i broke dd2005.


Now its giving me all sorts of off the wall numbers, with unported 416s and a xe262 it shows 862HP! lol

 

I guess its all in the info you're working with.

1. you will not achieve 100% volumetric efficientcy. 85-90% is a good job on this level of motor build. Therefore the 550cfm input not 750.

2. I got more than 217/159cfm from my ported 416 heads.

Did the heads have the stock 1.84x 1.50 valves or...?

I use larger than stock 1.94-1.60 valves.
My worst first effort resulted in 224/140cfm.
best was 239/180.
I've ported and flow tested quite a few sets.

I built a motor with my heads on a 12.65:1 cr 350 with a strip dominator/750 and a huge 287-292-.550" solid cam and did not get close to 480 hp. estimate 430hp within 10hp +/-.

have helped friends build motors just like the one you have planed with ported 305 heads and the power is about 370-390 tops with those parts. Good results for the $$$'s spent.

We've been working with desk top dyno and a few other engine building programs and comparing their perdicted results to real dyno results over the years and have uncovered the flaws(mostly in the instructions on what to enter to properly model the engine you're building.
It's very easy to over state the modeling for a selected part. Like the cylinder heads.

Try what I suggested and then play with the parts ( camshaft timing, manifold etc and see what can be done with different stuff.
I think you'll be much closer to the truth and not dissapointed or misled with the real results.

 

I wouldnt "expect" it to put out 480hp, actually i would be kind of happy if it didnt. it would just twist the rest of my driveline to pieces


I havent measured the valves but i suspect their still the 1.84/1.5s


I dont see how anything i have entered for the head will screw up the results because im not using the "mild port" selection or anything, just cold hard numbers from the ported heads.


Maybe my whole systems gone to lunch, would you be able to punch up this setup and see what numbers you get?

edit: with 600cfm holley it comes up with 470/464 but at 98/92% ve

 

The latest version of Desk top dyno I have here is
DD2003.

i used dyno 25 ( old dos version) to get a quick easy output.
( been using this stuff for years)

I'll work with DD2003 tommorow and Engine analyser ( another good one) after work and see, but I know I'm close reguardless of what version used.

What is different between DD2005 and older 2003 version?
600cfm is getting closer to the truth but still over states how much air the real motor is actually consuming. (I know it tells you to enter the carb cfm size).

Try increasing the cfm setting, just for grins. You'll see that as long as you keep increasing that setting power goes up. But in the real world it does not work that way.
550-600cfm is closer to the truth and get the predicted output closer to actual experience.

Hope I haven't burst your bubble too bad.....

 

Im not sure what dd2003 will say for this as i only have dd2000 and dd2005.


You havent burst much, i was still wondering how a basically stock motor would put out almost 500hp lol. i do find it weird though, that both simulators came up with similar numbers.

 

send me the airflow file that you made from the flowtest you used.

 

Easy...

Put in "single plane intake manifold", "aggressive roller cam", "headers", overestimate your compression by "conveniently" leaving out the deck clearance and head gasket volumes, etc.

Garbage in, garbage out. They're just calculators. Punch in the numbers, out comes the answer. Doesn't have any way of verifying that the numbers you punch in actually mean anything though.

 

RPM Torque HP
2580 319 157
2800 377 201
3200 382 233
3400 381 247
3600 386 264
3800 407 294
4000 418 318
4200 424 339
4400 424 355
4600 417 365
4800 402 368
5000 394 375
5200 382 380
5400 371 381
5600 353 376
5800 341 376

This is a real dyno test from a real 350.
It has a Xe268H10 and stock vortec heads, rpm air gap and a 625demon and 9:1 compression.

this is a good example of what you should be able to achieve with the ported 305 heads and a XE268 cam

If you were to port the 305 heads *like I do* using larger 1.94x 1.60 valves and build the motor with 10:1 compression you would be very very close to this power.
+/- a few ponies.
If you use stock valves the power will be less
You can see from the torque curve that a 3000-3500stall would just rock.
3.73-4.10 rear gears are just right.
Source: Sallee Chevrolet

 

Most of you should dump desktop dyno and get Performance trends Engine Analyzer. Its far more accurate and gives you lots of realistic conditions that you may not know about.

 

Yup Its a good one.

 

damn f-bird, thanks! That's the kind of real world numbers I like to see....
I'm hoping my build gets that kind of power, very impressive!

 

Still not too bad of numbers, ill be running just over 10.5:1 CR with all the components i have unless i end up doing something with the chambers on the head but i think ill just leave them alone.


Im still not 100% sure what ill be doing with the rest of the drivetrain but heres what i have to work with:

Th350c
Th700R4
PG
3.23s
4.11s

Both TH trannys have stock stalls so its going to cost a small fortune to get a new TC for either trans.


Were those dyno numbers at the crank or wheels?