C5R port vs. LS catherdal port
05-16-2005, 08:06 AM
#21
Originally Posted by cary et performance
BTW, The Cathederal port was a great concept by GM to get the cross sectional area they needed though the narrow pushrod restraints.
to answer the original question:
one of the design constraints of the genIII motor was that they had to keep the pushrods "straight".
this meant that they were limited in port width... so they did the best they could within those design constraints.... and they did a good job too
with the C5R program, they didn’t have those limitations... so one of the first things they did was change the intake port layout and just angled the pushrods.
after years of racing, the design showed its durability and GM felt confident enough to put a similar valve train design into production for the limited edition LS7
05-17-2005, 11:42 AM
#22
Originally Posted by cary et performance
The LS7 manifold still wont fit the C5R heads. The bolt pattern is different, and the port shape is also a bit different. The LS7 cylinder head is a purpose built 427 big bore cylinder head. it does flow well though. We will be offering the ls7 port configuration, with the option of a small or large bore, as well as the smaller valve and port volume. Yes the LS7 ports are large.
There is an aftermarket head that will become avalible within the next two weeks that will offer a solution to almost everyones issues with port volumes, chamber volumes, valve sizes and is avalible in a cathederal port version and a c5r/ls7 port configuration, the price will be attractive. We will have a complete breakdown and dealer list on our website by next week. Manifolds will be avalible for the c5r/ls7 versions right behind it. One of our first releases will be our cathederal port 4.00 bore 2.100 intake valve 265 cc 11 degree valve angle. 381 cfm @ .700 lift 357cfm@ .575 lift. This is what will fill the void in the larger displacement engines 400-440 cubic inches. There is too much to list in one post. So for the guys that are currently looking for a well thought out, well engineered cylinder head, look out for the new ETP G3 15 and 11 degree cylinder head By ET Performance
BTW, The Cathederal port was a great concept by GM to get the cross sectional area they needed though the narrow pushrod restraints.
There is an aftermarket head that will become avalible within the next two weeks that will offer a solution to almost everyones issues with port volumes, chamber volumes, valve sizes and is avalible in a cathederal port version and a c5r/ls7 port configuration, the price will be attractive. We will have a complete breakdown and dealer list on our website by next week. Manifolds will be avalible for the c5r/ls7 versions right behind it. One of our first releases will be our cathederal port 4.00 bore 2.100 intake valve 265 cc 11 degree valve angle. 381 cfm @ .700 lift 357cfm@ .575 lift. This is what will fill the void in the larger displacement engines 400-440 cubic inches. There is too much to list in one post. So for the guys that are currently looking for a well thought out, well engineered cylinder head, look out for the new ETP G3 15 and 11 degree cylinder head By ET Performance
BTW, The Cathederal port was a great concept by GM to get the cross sectional area they needed though the narrow pushrod restraints.
Interested in it if so.... I have some C5R heads sitting next to me that need a home.
Bret
05-17-2005, 03:43 PM
#23
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Originally Posted by cary et performance
The LS7 manifold still wont fit the C5R heads. The bolt pattern is different, and the port shape is also a bit different. The LS7 cylinder head is a purpose built 427 big bore cylinder head. it does flow well though. We will be offering the ls7 port configuration, with the option of a small or large bore, as well as the smaller valve and port volume. Yes the LS7 ports are large.
There is an aftermarket head that will become avalible within the next two weeks that will offer a solution to almost everyones issues with port volumes, chamber volumes, valve sizes and is avalible in a cathederal port version and a c5r/ls7 port configuration, the price will be attractive. We will have a complete breakdown and dealer list on our website by next week. Manifolds will be avalible for the c5r/ls7 versions right behind it. One of our first releases will be our cathederal port 4.00 bore 2.100 intake valve 265 cc 11 degree valve angle. 381 cfm @ .700 lift 357cfm@ .575 lift. This is what will fill the void in the larger displacement engines 400-440 cubic inches. There is too much to list in one post. So for the guys that are currently looking for a well thought out, well engineered cylinder head, look out for the new ETP G3 15 and 11 degree cylinder head By ET Performance
BTW, The Cathederal port was a great concept by GM to get the cross sectional area they needed though the narrow pushrod restraints.
There is an aftermarket head that will become avalible within the next two weeks that will offer a solution to almost everyones issues with port volumes, chamber volumes, valve sizes and is avalible in a cathederal port version and a c5r/ls7 port configuration, the price will be attractive. We will have a complete breakdown and dealer list on our website by next week. Manifolds will be avalible for the c5r/ls7 versions right behind it. One of our first releases will be our cathederal port 4.00 bore 2.100 intake valve 265 cc 11 degree valve angle. 381 cfm @ .700 lift 357cfm@ .575 lift. This is what will fill the void in the larger displacement engines 400-440 cubic inches. There is too much to list in one post. So for the guys that are currently looking for a well thought out, well engineered cylinder head, look out for the new ETP G3 15 and 11 degree cylinder head By ET Performance
BTW, The Cathederal port was a great concept by GM to get the cross sectional area they needed though the narrow pushrod restraints.
05-19-2005, 03:23 AM
#24
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Originally Posted by DAPSUPRSLO
Boy, that sounds reall good for a 408. What about the rocker arms, is there something available now for this 11 degree angle? The c5-r heads are 12 right. Guess it's close enough not to make a huge difference.
To answer the intake manifold question, we are making a manifold that will fit under the camaro/ firebird / corvette hood that will fit the c5r style head,
be its design it will support torque below 3500 rpm. Nobody wants to lose drivability I would assume. side by side will be a race manifold that does not fit under the stock cowl, intended for racing purpose outside of the f-body crowd.
cary
05-19-2005, 05:07 PM
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those are damn nice looking rods, and heads, wish I had the cash to buy the car
I wonder how much the motors and or internals are going to run.
or the heads, I bet theyd be a nice addition as well
I wonder how much the motors and or internals are going to run.
or the heads, I bet theyd be a nice addition as well
