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Discussion Starter · #3 ·
I try to keep cylinder swirl under control with good short turn shape. These heads are probably some of the only 60's heads that have a sorta modern swirl pattern. More modern heads seem to swirl some at low lifts and then swirl drops from 1/3 to 2/3 lift and the swirl usually starts to come back as the discharge coefficient starts to fall off. Most old heads start swirling and keep getting faster and faster as you keep opening the valve. No tumble characteristics at all.
Squish to bore ratio is where I usually look for chamber activity.
These heads have the bad spark plug in the hole trick like an FE. So keeping the fuel from falling out of suspension over the Grand Canyon is one place you can find something as far combustion quality is concerned. That is about the only thing they started to improve on later small block heads.
 

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Why 8mm and not 7mm stems?

Rules? :unsure:
 

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Discussion Starter · #5 ·
Rules, 5/16 stems were the smallest allowed. LS valves are just a close fit. My heads have 8mm guide liners.
I'm sure we can all debate it, but if I was trying to get lighter than 8mm I'd probably go with hollow 8mm.
7mm is cool, but its kind of no mans land for me. I'm ultra familiar 4.5mm-6.0mm seeing how powersports heads are one of my biggest revenue sources. 8.0mm and larger have been common for years in the automobile scene. 7.0mm is kind of weird keepers, retainers, guides etc. fairly custom.
 

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I hate dumb rules! :LOL:



The 7mm was not that hard to obtain the correct components. This set up runs well into the mid-8K RPM range with a stock hydraulic roller lifter and 190# on the seat...
 

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Discussion Starter · #7 ·
Are the valves custom order? Are the retainers keepers and springs from COMP?
I like your setup, looks good.
Truthfully 5/16 is almost strange these days. 8mm LS super easy, fairly simple upgrade. One thing about swapping parts is function. The LS nailhead intake valves thrive in the SBF. Go figure head layout isn't really that much diffrent. Finding the 15* tulip exhaust was a little tough. I think the part number is F6232
 

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Best if I private message the info. ;)

FWIW I find the 5/16" valves easier to obtain for the type of street/track cylinder head projects that my customers want. Especially with titanium and inconel valve combinations. Trying to find a top shelf manufacturer of custom 8mm titanium intake valves would put me in the poor house compared to the 5/16" Ti valves that are available almost anywhere. Keeping a lot of versions of locks and retainers for these combinations on the shelf does help too but there are times when the lead times are insane, I place bulk orders, just in case the supply is short.
 

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Discussion Starter · #11 ·
The difference most of the time is what you're working on. They both have there place 5/16 is more of a race part. 8mm is more OEM type. (Keeper and retainer packages can be wildly different). Its all about what you are used to.
OEM Performance Replacement stuff is typically a day away at half price. But if you cant find something that will interchange with what you're working on than custom or race parts are what you need. SBF has always been an easy swap with some kind of chevy valve. Our Y Blocks not so much, they need +.200 with a 1.94 diameter and that is just not a common part so we buy those deep. Its all about what you're working on.
 

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The difference most of the time is what you're working on. They both have there place 5/16 is more of a race part. 8mm is more OEM type. (Keeper and retainer packages can be wildly different). Its all about what you are used to.
OEM Performance Replacement stuff is typically a day away at half price. But if you cant find something that will interchange with what you're working on than custom or race parts are what you need. SBF has always been an easy swap with some kind of chevy valve. Our Y Blocks not so much, they need +.200 with a 1.94 diameter and that is just not a common part so we buy those deep. Its all about what you're working on.
This all pretty similar to what Bill does for the 289 heads that have to run FIA prep in vintage (ie: stock castings)?

A family friend who raced a Shelby Cobra back in the day had AFR do his heads / intake in 1969, worked with Harvey Crane and Chase Knight on a cam, ran a Holley 750 baseplate on the stock carb, and they developed an exhaust on his dyno that was worth 30hp over H&M's sidepipes. Made just over 350bhp at the crank. Good enough for multiple regional SCCA Championships, lap records often faster than the A-Production 427ci Cobras / Corvettes, and finished 2nd to a 327 '69 Vette at the SCCA National Championship. Not bad for a former 260ci car (updated to 289ci) that had bump steer measured in inches. The FIA rule set is pretty similar (minus pump gas which limits compression), but I imagine they're over 425bhp now.

Edit: Found a post from Bill on ST
The FIA european spec 289's that we build will typically have either production 289 head castings or the better C6FE heads, depending on the chassis engine is going into. We run 11.25 CR compared to EMC max of 10.5. FIA mandates correct vintage heads and blocks, flat tappet cam and lifters,stock type rockers-- NO ROLLERS ALLOWED!The only intakes allowed are the stock Shelby's,performer rpm,or webbers. Obviously, this makes it tougher to make reliable power. Typical output is 380 tq and 450 hp with production passenger car heads and 20+ more with the GT-40 C6FE heads. In USA 289 engines we are allowed to use the better 351W and C6FE heads and high compression ratio.500+ hp common. Some sanctioning bodies like SVRA allow aftermarket iron heads and roller valvetrains.580+ hp achieved with proper budget B production 289's .Performer RPM intake still required.T/A 310 cid versions 600+ with dual plane, 620+ with Vic Jr. Because of the way the rules are written, we never build any 289's with C5AE production heads and roller valvetrains. If we did, power in the 500 neighborhood is possible. Peak hp would occur at a higher rpm than scored by EMC though.
 

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Since we are on 289 heads... Here's mine... ported these right before all the aftermarket stuff came out. (Well, the AR SBF was out, but I couldn't afford those. lol) These were daily driven 100 miles to college, then 40 miles each way back and forth to work from there. Ran 10.63 @ 126 in a 3300 lb 1966 mustang with a stock Toploader 4-speed... and a 200hp nitrous plate. Went 7.48 @ 92 in the 1/8 n/a. SFT 236/248 @ 0.050 @ 110 (Comp 282S intake, Comp 294S exhaust) Daily driver street car that embarrassed a LOT of cars street racing that should have beat it on paper back then... as ALL small block Fords were slow before aftermarket heads came out. lol

An intake bowl eventually cracked, so I drilled a hole to clean/epoxy the water jacket side of the crack with JB Weld. (see first picture) Ran the heads for YEARS after that without issue. After they had been run for 12-15 years with the occasional freshen-up, I sent one of them to get flowed. With the old valve job, they went 217 intake and 176 exhaust. May have the full sheet somewhere. I don't have a flow bench, and did these decades ago as a kid. Just an amateur compared to most of you. I did take them off every year or two to touch up the port job. Would use the carbon tracks to see where the dead areas were.

Chambers are probably too big, and the exhaust ports had the ugly air port... C6 castings... and likely ended up too big as well. 1.94"/1.60" valves. The left side of the intake port has an S curve in it. I make it a straight shot to the valve, and try to center the guide in the port the best I can. (Do NOT try this on a 351W head... or you will find water. lol) Intake ports ended up at 155cc. Stock is supposed to be 126cc. Takes a LOT of grinding. I also make the exhaust roof a straight line from the roof of the port exit to the top of the bowl... grinding out all the valve guide and boss that sticks out. Dove rockers and very little guide wear over the years.

I did these with STONES and a 2500 rpm hand drill. No carbide. The longer stones were hard to find before the internet. Hours and hours and hours... lol







 

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Discussion Starter · #15 ·
Your story reminds me of alot of my first 289. Valve sizes, porting ideology, and tons grinding time. Even your 351w learning, I bet I've put holes in those heads right in the same places. I'll bet your engine impressed you enough to want to keep playing with engines though. The 351W heads never impressed me for 289 and 302. A whole point of compression lossed was hard too swallow.
 

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Respect, that reminds me of where I first got started when I was 16. Real nice work for back then and I know what you mean about surprising people with a SBF.
Since we are on 289 heads... Here's mine... ported these right before all the aftermarket stuff came out. (Well, the AR SBF was out, but I couldn't afford those. lol) These were daily driven 100 miles to college, then 40 miles each way back and forth to work from there. Ran 10.63 @ 126 in a 3300 lb 1966 mustang with a stock Toploader 4-speed... and a 200hp nitrous plate. Went 7.48 @ 92 in the 1/8 n/a. SFT 236/248 @ 0.050 @ 110 (Comp 282S intake, Comp 294S exhaust) Daily driver street car that embarrassed a LOT of cars street racing that should have beat it on paper back then... as ALL small block Fords were slow before aftermarket heads came out. lol

An intake bowl eventually cracked, so I drilled a hole to clean/epoxy the water jacket side of the crack with JB Weld. (see first picture) Ran the heads for YEARS after that without issue. After they had been run for 12-15 years with the occasional freshen-up, I sent one of them to get flowed. With the old valve job, they went 217 intake and 176 exhaust. May have the full sheet somewhere. I don't have a flow bench, and did these decades ago as a kid. Just an amateur compared to most of you. I did take them off every year or two to touch up the port job. Would use the carbon tracks to see where the dead areas were.

Chambers are probably too big, and the exhaust ports had the ugly air port... C6 castings... and likely ended up too big as well. 1.94"/1.60" valves. The left side of the intake port has an S curve in it. I make it a straight shot to the valve, and try to center the guide in the port the best I can. (Do NOT try this on a 351W head... or you will find water. lol) Intake ports ended up at 155cc. Stock is supposed to be 126cc. Takes a LOT of grinding. I also make the exhaust roof a straight line from the roof of the port exit to the top of the bowl... grinding out all the valve guide and boss that sticks out. Dove rockers and very little guide wear over the years.

I did these with STONES and a 2500 rpm hand drill. No carbide. The longer stones were hard to find before the internet. Hours and hours and hours... lol







 

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Your story reminds me of alot of my first 289. Valve sizes, porting ideology, and tons grinding time. Even your 351w learning, I bet I've put holes in those heads right in the same places. I'll bet your engine impressed you enough to want to keep playing with engines though. The 351W heads never impressed me for 289 and 302. A whole point of compression lossed was hard too swallow.
It became an addiction. lol
I was subscribed to, and read pretty much every magazine out there and bought every book I could find that seemed like it had relevant information.

Most guys back then (before the internet) raced the cars they actually drove on a regular basis. Plus, GOOD information was hard to come by! You couldn't just go on the computer and look at everyone's combos and see what worked, ask questions, etc... Had to use your own intuition. LOTS of terrible combinations out there that didn't run anywhere near their potential. My little car was outrunning the vast majority of cars that 'should' easily outrun it on paper. Most people just had NO CLUE how to build a good engine combination, use the right converter, gear, tune a nitrous system anywhere near right, etc.

After the internet became a big deal and all the aftermarket heads and affordable stroker kits came out... it became a LOT easier... and ANY idiot could mail order a nice set of heads and a good combination. Before that, YE WHO WAS GOOD WITH THE GRINDER was usually the one to beat.
 

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FYI... Found the flow numbers for the old 289 heads. This was with a standard 3 angle valve job with several years worth of regular use on it... if that matters.

I was pretty proud of it for the time, and being an amateur without a flow bench. Once ported, the exhaust ports are NOT weak on these heads... as many believe. It's the tiny intake ports that start at a paltry 126cc. Lol

Intake -- Exhaust

.1 063 -- 050.9
.2 119 -- 101.3
.3 168 -- 132.8
.4 201 -- 157.1
.5 210 -- 175
.6 218 -- 176.6
 
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