When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
This is a set of hand ported 823 L92 heads for my 377 6.2 build. These were flowed on a SuperFlow 600, the benchmark of the industry . This machine does have a swirl meter and analysis/summery software. This head was flowed with 1/2” radius rolled clay but nothing on the exhaust port. CFM is in the far right column.
Thanks for sharing that good information.
The exhaust flow is certainly quite weak especially with a 4.155 bore plate.
What cc is the intake and exhaust after porting?
That's a 62% intake/exhaust ratio which will require a cam with a good split.
Are you going to re-flow after a proper valve job? I’d expect the exhaust to improve.
About throat to valve ratio. I read numbers like 80%. Maybe 90%.
Is there a preferred goal?
From my amateur port work on stock heads it doesn’t seem like you can get there unless you install bigger valves.
I just had my untouched AFR 205’s apart, and a quick measurement on those showed a 90% ratio. 2.02/1.60 valves. Just some interesting data.
I’ve not had any of my work flow tested. One of the builders I use has a fancy Superflow bench, and every time I ask about it he says “want to buy it?” Ha.
One thing about not having my stuff flowed, saves me any potential embarrassment. 😊
Are you going to re-flow after a proper valve job? I’d expect the exhaust to improve.
About throat to valve ratio. I read numbers like 80%. Maybe 90%.
Is there a preferred goal?
From my amateur port work on stock heads it doesn’t seem like you can get there unless you install bigger valves.
I just had my untouched AFR 205’s apart, and a quick measurement on those showed a 90% ratio. 2.02/1.60 valves. Just some interesting data.
I’ve not had any of my work flow tested. One of the builders I use has a fancy Superflow bench, and every time I ask about it he says “want to buy it?” Ha.
One thing about not having my stuff flowed, saves me any potential embarrassment. 😊
Nice work btw.
Ron
I might, the bench owner told me I was welcome to retest the head with out added cost. He also explained to me that a 2” pipe on the head would add additional exhaust flow, maybe 10-15cfm, so maybe a good valve job and headers will help the exh. port flow. I have a machinist that uses a Serdi machine that gives the exh. seat a full radius cut and that is supposed to enhance flow some.
No hogging out, I left the intake runner cross sections pretty much stock size, I removed the many bumps in the port including the huge one on the S shaped wall, streamlined the guide bosses, blend the bowls 360* land leave the short side drop alone, just smooth it. I think it’s a good plan now that I’ve seen the results. That .300 number is ridiculous.
In for Dyno numbers on an LS3 just sent my ls3 heads out to TEA for a stage 2 CNC , VJ, and Mill.
Yes, me too. not sure where to get it done around here. Using Holley system. Going to use an LSXR 102, CamMotion ground cam specced by Navy Blue, 11.7:1 SCR, about 8.8 dynamic, Texas Speed roller tip 1.72 rockers, long tubes through a 3” X pipe system through a TH350 3500 stall, goal is 535 rwhp.
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Ported 823 heads 
just sent my ls3 heads out to TEA for a stage 2 CNC , VJ, and Mill.