S&S 79cc Heads
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Road Warrior
Joined: Jul 2011
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From: Central TX
S&S 79cc Heads
I have read about going too large valves on heads can cause loss of low end as air velocity slows down - seems most comments I have read on this concerns too large exhaust valve slowing down exhaust gases. I have been looking at different heads for my 95" engine and saw these S&S 79cc heads with description below. They have large intake 1.94, but exhaust valve is smaller - 1.575. I was thinking of using these with with either a HQ0039G or TW6HG cam. Will the large intake hurt performance? I have read the HQ asymmetrical lobes with short exhaust duration forces the exhaust vacuum to pull air in during the intake stroke. Would this help keep intake velocity up for good cylinder fill? Trying to learn here - any help is appreciated. Thanks.
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
Last edited by txphatboy; Oct 28, 2014 at 06:00 PM.
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The "shark fin" or better named vortex generator, in the intake runner of those heads maintains a good velocity and the runner being as large as it is, allows good volume on the spool-up.
That 1.940" valve head is not too big for you.
We've used our 2.02" Stage IV Heads(that far out-flow those S&S Heads) on variations of our HO 98" combo's.
Only issue we see with those is your face hurts from grinning so much.
Scott
That 1.940" valve head is not too big for you.
We've used our 2.02" Stage IV Heads(that far out-flow those S&S Heads) on variations of our HO 98" combo's.
Only issue we see with those is your face hurts from grinning so much.
Scott
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Joined: Oct 2010
Posts: 66
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From: Ohio
I have read about going too large valves on heads can cause loss of low end as air velocity slows down - seems most comments I have read on this concerns too large exhaust valve slowing down exhaust gases. I have been looking at different heads for my 95" engine and saw these S&S 79cc heads with description below. They have large intake 1.94, but exhaust valve is smaller - 1.575. I was thinking of using these with with either a HQ0039G or TW6HG cam. Will the large intake hurt performance? I have read the HQ asymmetrical lobes with short exhaust duration forces the exhaust vacuum to pull air in during the intake stroke. Would this help keep intake velocity up for good cylinder fill? Trying to learn here - any help is appreciated. Thanks.
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
What engine/compression ratio were you thinking of using these heads on ?
spending $1200+ for a set of heads for a bolt in cam seems like a waste of a decent head....and the S&S 79CC heads are pretty decent out of the box ....and have lots of potential for upgrading in the future.....pretty sure id shitcan the stock springs for a bolt in or even a step up for a bolt in cam...way overkill
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Joined: Dec 2007
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I have read about going too large valves on heads can cause loss of low end as air velocity slows down - seems most comments I have read on this concerns too large exhaust valve slowing down exhaust gases. I have been looking at different heads for my 95" engine and saw these S&S 79cc heads with description below. They have large intake 1.94, but exhaust valve is smaller - 1.575. I was thinking of using these with with either a HQ0039G or TW6HG cam. Will the large intake hurt performance? I have read the HQ asymmetrical lobes with short exhaust duration forces the exhaust vacuum to pull air in during the intake stroke. Would this help keep intake velocity up for good cylinder fill? Trying to learn here - any help is appreciated. Thanks.
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
Heads are fully assembled with springs and valves, and are available in silver or wrinkle black.
79cc heads work great with stock motors for 88" to 103" motors; 89cc heads work best for motors over 103" or with high-compression pop-up pistons
79cc have 1.940" intake and 1.575" exhaust valve and springs for up to .640" lift;
79cc heads accept OEM rocker boxes
Manufacturer: S&S Cycle
Manufacturer Number: 90-1293
Fits: 1999-2005 Harley Twin Cam
Preview Instructions: Yes
Scott
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Joined: Dec 2007
Posts: 12,084
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www.maliburacing.com/johnwalker is this torqueinc character, gentleman, and if that is not enough, check the thread on the CVO site to take a look in the vendors section, WOW!!, as a leopard does not change it's spots........
Suprised the moderaters here, at this point, allow him to even be able to view this site, say nothing about coming here only to contradict, sling disparaging remarks, and poison.......
Scott
Suprised the moderaters here, at this point, allow him to even be able to view this site, say nothing about coming here only to contradict, sling disparaging remarks, and poison.......
Scott
Last edited by Hillsidecycle.com; Nov 6, 2014 at 04:21 AM.
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Joined: Oct 2010
Posts: 66
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From: Ohio
Isnt that like the pot calling the kettle black ?
This nonsense coming from a guy that has been banned from half the existing internet Harley forums for the very thing you are accusing me of.
And yes Scott I am going to contradict you or anyone else vendor or not who suggests a $1200 set of heads for a bolt in cam.
Preying on the low information Harley riders....shame on you
This nonsense coming from a guy that has been banned from half the existing internet Harley forums for the very thing you are accusing me of.
And yes Scott I am going to contradict you or anyone else vendor or not who suggests a $1200 set of heads for a bolt in cam.
Preying on the low information Harley riders....shame on you
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www.maliburacing.com/johnwalker.
CVO site vender section.....
Case closed............guilty as charged.
CVO site vender section.....
Case closed............guilty as charged.
Last edited by Hillsidecycle.com; Nov 7, 2014 at 07:11 AM.
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No mud, all facts if you look, and if you also take notice he was banned, so it looks the moderators here took a mighty dim view of HIS continued and ongoing harrassment.
He was more than exposed on the CVO site, by 3 different shops with product theft, harrassment of businesses, harrassment of their clients, etc, and by several individuals as well that had direct dealings with him, which also included theft.
Same/same on that car forum.
MUCH more to this whole thing than you are apparantly aware of.......
I've no more to say on this matter, so please, do not try to drag this out into something that shouldn't be...
Scott
He was more than exposed on the CVO site, by 3 different shops with product theft, harrassment of businesses, harrassment of their clients, etc, and by several individuals as well that had direct dealings with him, which also included theft.
Same/same on that car forum.
MUCH more to this whole thing than you are apparantly aware of.......
I've no more to say on this matter, so please, do not try to drag this out into something that shouldn't be...
Scott