Ported Chevy 487x heads

[F-BIRD'88]

It is great that you are on the game and checking the bench flow calibration
for accuracy.
You are doing a great job reguardless.

it would be interesting to see some of the heads you have done (very well IMHO) like the 081's
tested on a motor eg a 355 or a 383. See how much power and torque the ported heads create.

[GARY C]

When I bought my SF110 years ago it came with a home made lift fixture and after some issues I realized it was flexing and losing 10 to15 thousands lift, the next thing I ran across was that the springs were to soft and if you tried to test low lifts at 15" it would pull the valve open.

I ended up making 2 test plates one at 105 and some change and one at 257 and some change and then had them tested on 2 known SF600's it turned out my bench was exact on the small plat but 1 cfm high on the big one so if I ever get a flow # that seems above the average good porter I question myself and have them confirmed on another bench.

I am actually surprised no one questioned your #'s after page 2, I wanted to say something but I'm a nobody and would have been attacked for saying something.

Your last posted flow sheet would be in line with what I would expect to see from that head with a 2.02 valve.

[Carnut1]

When I bought my SF110 years ago it came with a home made lift fixture and after some issues I realized it was flexing and losing 10 to15 thousands lift, the next thing I ran across was that the springs were to soft and if you tried to test low lifts at 15" it would pull the valve open.

I ended up making 2 test plates one at 105 and some change and one at 257 and some change and then had them tested on 2 known SF600's it turned out my bench was exact on the small plat but 1 cfm high on the big one so if I ever get a flow # that seems above the average good porter I question myself and have them confirmed on another bench.

I am actually surprised no one questioned your #'s after page 2, I wanted to say something but I'm a nobody and would have been attacked for saying something.

Your last posted flow sheet would be in line with what I would expect to see from that head with a 2.02 valve.

Gary You are far from a nobody, You always have intelligent input. Why did nobody call out the numbers as bullshit? I am not sure. I thought I was pretty close. I also thought my bore fixture was 4.3". It was built to be reversable I think 4.3" and 4.110" so everything I have flowed was at 4.11" bore. No wonder I had such issues with the big block stuff hitting the bores! My numbers from here on in will be more realistic but I plan to still get guys pissed! Life IS a competition,

[GARY C]

I asked about the dyno testing on page 1 because I didn't want to jump to conclusions and I didn't know if maybe you had found something new with you valve seat and top cut, I know of some current testing on production heads with less than 45 seat and a non conventional top cut.

Looks like it was starting to work, in the mid it did take the top off a number or two and it did some correction to swirl.As you loose swirl it should pick up a little flow. Shame you couldn't have got the full 55 on it. Some times it is a winner sometimes it is not. Like I said I've never done it with a full radius valve job. (that cutter)
Just have to test it.

I don't have cutters. Only old Sioux stones that I can shape to a radius.

But after this post on page 2 I started wondering about your #'s vs valve size if it was only a 45* type seat cut especially the .100 numbers because valve size and seat mostly predict that flow # and then the rapid gain in flow did not seem normal for the valve size are seat.

BTW, thanks for the compliment, I really am nobody, I have just been lucky enough to know some good people and I like to study... (some things).

[GARY C]

My fixture is a 4.00/4.250 I flow most on the 4.250 and will occasionally flip it to the 4.00 bore for comparison and it's about 12 cfm more on the big bore at .700 lift the way I do my heads.

[Kenny M]

I just purchased a used superflow 600 with flowcom. I thought the numbers were high also. I purchased three calibration plates from Performance trends. My bench was 20% high at low lift and 5% high at high lift. A good friend of mine Steve Brule at Westech says a easy way to get a general idea if the bench is close is to look at the 050 and .100 numbers on almost all heads it will be around 30 cfm and 70 cfm.

[Carnut1]

Funny to reread this thread now. Anyone notice the ssr on the 487 heads? May explain the very high swirl these heads produce. Thanks, Charlie

[user-612937456]

Charlie if you don't care could you give a critique of your work and tell us what you would do differently or not after the fact?

Could you improve your results after DV's Seminar and porting software?

Or is this all these heads will reasonably give up?

[Carnut1]

Charlie if you don't care could you give a critique of your work and tell us what you would do differently or not after the fact?

Could you improve your results after DV's Seminar and porting software?

Or is this all these heads will reasonably give up?

Answer: If the Sept 8th is not full and I can borrow or beg for time off and $ to get it done I would like to come to the next one.

I have two jobs to finish first but this set of heads would be interesting to revisit as far as porting, new sonic, Pitot testing and DV program.

With what I have learned in the last year I would say I can better these by a bit if there is enough casting thickness to make changes!
Thanks, Charlie

[user-612937456]

Let me rephrase my question Charlie if you had a set of virgin 487X heads what you would do differently? What would expect to get the second time around?

[Carnut1]

Let me rephrase my question Charlie if you had a set of virgin 487X heads what you would do differently? What would expect to get the second time around?

Good question, I would take detailed port size, Pitot airspeeds, ssr shapes and baseline flow, velocity and port energy graphs. I think what I would do differently would depend on the application. Really documenting the starting point helps the direction and gains. At some point the gains stop or even reverse and you would be better off where you were a week ago! The program is actually really well designed in that capacity if you are the organized type. You can graph last week's ports against today's or today's vs. starting ports.

[GARY C]

I just purchased a used superflow 600 with flowcom. I thought the numbers were high also. I purchased three calibration plates from Performance trends. My bench was 20% high at low lift and 5% high at high lift. A good friend of mine Steve Brule at Westech says a easy way to get a general idea if the bench is close is to look at the 050 and .100 numbers on almost all heads it will be around 30 cfm and 70 cfm.

I like to use .025 lift and 22 cfm then the .050, .100, .150 give me an idea how well the seat is moving air. I usually see around 34 at .050 but have seen 65 to 73 @ .100...

[gmrocket]

Another one, really informative this new style of speedtalk showing relevant threads in the same topic

Charlie, can you post any final info on these heads on the engine?

[Carnut1]

These were a flowbench learning curve to see what could be done with the open chamber design. I did a bunch of open chamber heads in the late 80's and early 90's but that was way before the flow bench. They ran well for what they are. I preferred a closed chamber. Thanks, Charlie

[juuhanaa]

speaking of margin, which I like for my builds because they live longer
straight or break the sharp corners or full radius
when and why?

Nice work Carnut
I've never progressed much beyond your "old school" (starting from "hog them out big")

I would need to do some testing to answer the radius question. It does seem to increase flow, maybe decrease cone size around valve. Will also change your overlap flow, I would think increase overlap flow.

Nice porting aand interesting casting Im just thinking bigger chamber and ton of swirl toward the exhaust wouldnt hurt overlap.

Question: Letsay it has more overlap flow/flow across the chamber and exhaust itself is done. Can a head like this on a street combo go to later IVO, or wider lobe center (earlier EVO too and not so late IVO), or something else?


-juhana