600 ci NA build
#91
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Joined: Feb 2009
Posts: 8,356
Likes: 1,515
From: NW Michigan
It's supposedly same cam 900-1075 so maybe different springs, valve seats etc used on 900's that take a pounding. Not sure. Regardless you'd think Merc Racing would have endless R&D hours and could have come up with something with less maintenance/replacement intervals. I thought they used same or similar to your Teague SC's in the 1075's but evidently not. At least from what I could find out here on OSO. I've got two on the shelf but have my eyes on a couple with less aggressive lobes. Mike keep your old cam. I'd like to mock up and compare sometime.
#95
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Joined: Dec 2002
Posts: 2,195
Likes: 2
From: Dallas, TX
#97
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Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
Just having a cup of coffee playing with the Pipemax program.
606ci turning 6500RPM, making 900HP.
Recommended valve lift = MIN .786 Normal .885 Max 975
Required intake flow 381-404 CFM at .874 valve lift
Required exhaust flow 275-298 CFM at .948 valve lift
Carb CFM 1175-1440
Recommended cylinder head Cross sectional area 3.523 (A 357cc AFR has 3.435 min csa for reference)
Headers for low to midrange power
2.10 to 2.225 " Primary ID 32.4 to 35.6 inches long
Midrange to upper rpm power
2.30 to 2.425" Primary ID 32.4 to 35.6 inches long
Collector diameter
4.051 to 4.301 best for tq
4.301 to 4.801 best for HP
Not sure a set of Gils or E Tops would work well on this monster, or a "741" cam
606ci turning 6500RPM, making 900HP.
Recommended valve lift = MIN .786 Normal .885 Max 975
Required intake flow 381-404 CFM at .874 valve lift
Required exhaust flow 275-298 CFM at .948 valve lift
Carb CFM 1175-1440
Recommended cylinder head Cross sectional area 3.523 (A 357cc AFR has 3.435 min csa for reference)
Headers for low to midrange power
2.10 to 2.225 " Primary ID 32.4 to 35.6 inches long
Midrange to upper rpm power
2.30 to 2.425" Primary ID 32.4 to 35.6 inches long
Collector diameter
4.051 to 4.301 best for tq
4.301 to 4.801 best for HP
Not sure a set of Gils or E Tops would work well on this monster, or a "741" cam
Last edited by MILD THUNDER; 01-03-2018 at 06:07 AM.
#98
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Joined: Jul 2004
Posts: 11,332
Likes: 73
From: chicago
Dropping to a 2.25 valve from the 2.40 , minimum lift requirement increases from .786 to .838 .
Dropping the max RPM from 6500, down to 6000, minimum lift requirement decreases from .786 to .725 with the 2.40 valve.
Dropping the max RPM from 6500, down to 6000, minimum lift requirement decreases from .786 to .725 with the 2.40 valve.
Last edited by MILD THUNDER; 01-03-2018 at 06:09 AM.


