Hey martin@tick
10-25-2013, 07:50 PM
#41
Yeah, I get that. But that looks like an Edebrock Performer intake. The ports on those things have a very small cross sectional area. And, the way they are built, I don't know how you could port it effectively all the way to the plenum. While I am sure it would have amazing torque just off idle, it is going to seriously restrict the upper RPM range and peak horsepower of that 408.
10-28-2013, 12:57 PM
#44
Everything was designed with a 6200-6400rpm shift point and a 5600-5800rpm power peak in mind Steve.
With the cross section and the valve area the cylinder heads have, Matt should be able to accomplish such with the cam I've specified for him.
The cam I specified has a very early EVO event for the RPM range of this motor. I also specified the IVC event a little earlier to maximize average power. I also cut down overlap and widened the exhaust center line to try and make the torque curve as flat as possible in the lower RPM rpm ranges and past peak torque.
While the wider center line and early EVO for it's operating range will naturally lower peak torque, I felt that peak torque wasn't going to be an issue with 408 cubic inches and the manifold Matt had chosen.
This engine was never built with more than 6400rpm in mind and Matt made that clear to me on day one.
So I went with a larger port and cross section to try and crutch the manifold as well as utilizing the larger intake valve to crutch the manifold as well. The earlier EVO was also done with the smaller stock exhaust valve in mind.
I think it will be a stout combo that won't impress people with mind boggling peak HP numbers, but I think Matt can expect to see 450rwtq by as early as 2600-3000rpm!
I fully expect power to drop off after 5800-6000rpm which should allow the 6200-6300rpm shift point Matt wanted from the beginning.
If he ever wants more top end power, he is just a manifold swap and ICL adjustment away from accomplishing that.
With the cross section and the valve area the cylinder heads have, Matt should be able to accomplish such with the cam I've specified for him.
The cam I specified has a very early EVO event for the RPM range of this motor. I also specified the IVC event a little earlier to maximize average power. I also cut down overlap and widened the exhaust center line to try and make the torque curve as flat as possible in the lower RPM rpm ranges and past peak torque.
While the wider center line and early EVO for it's operating range will naturally lower peak torque, I felt that peak torque wasn't going to be an issue with 408 cubic inches and the manifold Matt had chosen.
This engine was never built with more than 6400rpm in mind and Matt made that clear to me on day one.
So I went with a larger port and cross section to try and crutch the manifold as well as utilizing the larger intake valve to crutch the manifold as well. The earlier EVO was also done with the smaller stock exhaust valve in mind.
I think it will be a stout combo that won't impress people with mind boggling peak HP numbers, but I think Matt can expect to see 450rwtq by as early as 2600-3000rpm!
I fully expect power to drop off after 5800-6000rpm which should allow the 6200-6300rpm shift point Matt wanted from the beginning.
If he ever wants more top end power, he is just a manifold swap and ICL adjustment away from accomplishing that.
10-28-2013, 02:40 PM
#45
Staging Lane
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thanks for spelling that out martin. and your right, after i get the combo together and decide i prefer something different your only a phone call away. martin and i talked about my needs and wants and went from there. like i said, if its not what i want then we can go a different route. thats the beauty of cars, all the different combo's. in the end its my money and my decisions. i dont come on here to look for validations on stuff, i call people who are more experenced and have real world data to help me achieve my goals. more people should pick up a telephone. this is a street car only.
10-28-2013, 03:27 PM
#46
No problem Matt.
Here is a great example of what I feel Matt is trying to accomplish, but on a larger scale obviously.
This is a 383 SBC GEN 1 motor we put together for a customer. Small solid roller camshaft, Trick Flow 185cc cylinder heads, Edelbrock Dual Plane manifold, 850 carb, 10.5:1+ compression through a 4 speed manual trans.
Note the early torque peak and early hp peak. Keep in mind, this is a SBC with a very small, very restrictive cylinder head in comparison to the 300+ CFM 232cc 2.08" intake valve cylinder heads that Matt has. Also Matt's compression is higher than this engine, and he has more cubic inches.
I expect to see a torque peak of 4400-4600rpm with Matt's engine and a 5600-5800rpm hp peak. What we're after here is average power and maximizing power under 6000rpm.
For a Gen 1 10.5:1 CR 383 street motor to make 400rwhp and 440rwtq is stout IMO. I feel Matt can make very close to 500rwhp with his combo and 475-480rwtq.
Here is a great example of what I feel Matt is trying to accomplish, but on a larger scale obviously.
This is a 383 SBC GEN 1 motor we put together for a customer. Small solid roller camshaft, Trick Flow 185cc cylinder heads, Edelbrock Dual Plane manifold, 850 carb, 10.5:1+ compression through a 4 speed manual trans.
Note the early torque peak and early hp peak. Keep in mind, this is a SBC with a very small, very restrictive cylinder head in comparison to the 300+ CFM 232cc 2.08" intake valve cylinder heads that Matt has. Also Matt's compression is higher than this engine, and he has more cubic inches.
I expect to see a torque peak of 4400-4600rpm with Matt's engine and a 5600-5800rpm hp peak. What we're after here is average power and maximizing power under 6000rpm.
For a Gen 1 10.5:1 CR 383 street motor to make 400rwhp and 440rwtq is stout IMO. I feel Matt can make very close to 500rwhp with his combo and 475-480rwtq.
