cv67

Brian Cunninghams heads freshly soda blasted and flowed...
Very similar to the #s pulled off the web, never hurts to double check it.








Heads and intake will be ported and the flowed (again) seaprately and together. Just for reference. Odd intake port shape.....
Ive seen #s printed out here but no charts yet, just curious.

Orr89rocz

does look pretty similar to stock LT1 heads i've seen...but i thought it would push closer to 205-210 on the intake side and 160-170 exhaust

BrianCunningham

Thanks for getting that done, man they cleaned up nice

This will both end of lot of debates, and start many more.

peaked at .400 lift!

Makes you wonder about putting big rockers on stock heads.

bogus

I was looking at those numbers myself. Most interesting they dropped a bit as the lift increased.

I suspect 1.6:1 rockers are still a good idea, if only for their consistancy of manufacture.

bobmic93

It peaked at 4 but only dropped off a few points all the way to 6500. Not to bad.

TenSecondZ

Great info... Could you post the Casting # ...

The later heads flow about 5-10% more according to Lloyd Elliott.

However, the earlier castings have more meat for an all out port job, hence the requirement for an earlier casting with either Advanced Induction or LE.

cv67

10128374 is the casting #.

There is a large 3179 stamped above that.

cv67

Had one intake and one exhaust flowed just to see where things were headed. Keep in mind each port is still in need of more work, chambers are untouched with an 80k mile vavle job on them.

Still plenty of room for improvement. Gotta say the exaust ports suck on these head out of the gate.


Intake



Exhaust (on left)




Tony Mamo at AFR was kind enough to spend some time on our lo-budget drone build and put them on the bench. Due to time constraints I didnt have timr to get these "done", but does give an idea of where wer'e at and what needs more attention.


The same port that was flowed before unported was flowed only this time it was done with a fixture in the intake to mimic a perfect entry (such as a ported intake ), and flowing the exhaust with a pipe. interesting to see the difference..

Below is the first shops results without those two items and the top line of the intake/exhaust on the AFR sheet also shows the same ports flowed with these differences. This is why having heads flowed at two different places can have 2 different results..Weve all seen these threads that result in flame wars, heres why.





+1 cfm @.200





Here is Tony in action




Wanted to thank Tony again for his time with our stuff.
-The Sheepster

VenkmanP

These do peak sooner than the other stock flow numbers I've seen, but why would it make you wonder about big lift? This flow sheet shows what we already know from real world results - that stock unported LT1 heads will support a lot more lift than the stock cam+rockers provide.

Curveit

and, that while the stock port flows 215 @.400, it flows 211 from around .380 on up to at least .550. So, with whatever cam duration you have, the port will be flowing nearly at its max, for more of that avaliable time.

cv67

More pics to come next week, betting the intake is now on its way to 270 and exhaust surpassing the 190 mark, still on stock valve size. We will see. Goal is to keep the intake runner as small as possible while acheiving this, not easy. Time, time, and more time.

Greg Gore

Look at the valve seats. The throat cut and how it is blended might respond to a change and show an increase. The port is peaking too soon, it should be capable of more flow than that. The drop after the peak at .400 was because the port is developing turbulance in the area of the valve seat. Rocker ratio increases lift under the curve and rate of acceleration of the valve off the seat. Comparing lifts at the valve with a degree wheel on the c/shaft will show increases everywhere not just peak lift.

bobmic93

Port velocity is important to keep that low end grunt.

cv67

I may wind up giving some up to get the bigger #s. Honestly I feel that whats there already is good enough for a mild 350 on the street.

Havent had tiem to mess with them lately, went to plan B. More to come...

Kevin Woods

Why would you say that?

What often gets lost on people is that in addition to producing more valve lift, the 1.6 rockers also increases the effective duration of the cam !

KW

comp

Curveit

I personally add 2* @ .050 going 1.5 to 1.6 rockers

racebum

same numbers almost to the T as the 113 casting. After some cartrage rolls, better valves {still stock size} i was able to get a set of 113s up to 231@.500 and 190@.500, mid lift gained similar percentages of +15-20% Probably had 8-10 hours in the set. The neat thing about 1.94/1.50 valves is they rev a few hundred rpm higher than 2.02 1.60s with the same spring. Those heads cleaned up great, did you ever consider tinkering out in your shop to pick up the flow? basic porting isn't as hard to learn as some people will have you think.

Daniel DK

So i guess skipping the 1.6 rockers and getting a cam with more duration would be a wiser choice? less valvetrain movement = better/cheaper high rpm ability?

Curveit

1.6 Rockers aren't gonna decrease your RPM abilities. Many motors run 1.7-1.8 stock (LS, BBC, Ford Cleve, etc.). Pure race motors sometimes run even higher; think 2.0. Whatever Cam you got, 1.6 are going to lift the valve higher, lift it quicker, and hold it open longer.
383s and bigger strokers can rev plenty high. 8-8500 if you've got the parts, and a good balance, to support it. If you're talking about 15-18000 then you might want a 2" or smaller stroke crank.