If i ever have the money somday I would like to adapt this to a SBC 383 (destroked 400)
I dont think any of you care but a 383 is typically a STROKED 350 using a 350 block and a 400 crank. This is probably one of the most popular motors around right now.
Although you can make a 383 by destroking a 400 with a 350 crank, and boring the 400 block .060 over which requires a EXPENCIVE block to do safely. So this 2nd type of 383 is very rare.
I dont think any of you care but a 383 is typically a STROKED 350 using a 350 block and a 400 crank. This is probably one of the most popular motors around right now.
Although you can make a 383 by destroking a 400 with a 350 crank, and boring the 400 block .060 over which requires a EXPENCIVE block to do safely. So this 2nd type of 383 is very rare.
The most common destroked 400 is a 377. Just a 350 crank in a 400 block. Depending on overbore you can hit 383 ci with it too.
It is still refered to as a 377 by most people even if bored a bit. That way people know what crank is in it.
Take plastic wedge shaped spacers and use them to alter the angle of the intake runner relative the intake port. Start at perpendicular work downward angle wise seeing if flow increases. Then flip the same spacers over to tilt it in the same graduations upward while benching it. 0 (perpendicular) - (down) + (up)... -15, -10, -5, 0, 5, 10, 15
There has to be a sweet spot for the runner angle.
Honda will probly be the first they suposidly have a 1.5L motor with a CRV head and the main issew is seal longevity. Same problem everyone is having. But your right if big three would jump in it would have been here by now. Imagine spinning any engine upwards of 12,000+ rpm. O well i can dream.
If you want that high of RPMs, I would invest in a wankle engine. Rotary engines are fundamentally masterminded for high rpms.
I will talk to Polk next week about this. He should have my 2G head back from getting CNCed any time so he could flow that one. Not sure if he has a stocker laying around though.
i think alot of people are going to be surprised with the flow of the 2g head, there should be a SMIM and 1g head vs. SMIM and 2g head. alot of you will be surprised. lets just say i bought a 2g head for my 1990 Tsi AWD
Port shape and velocity. The 2G intake port will flow more air on the short side radius as the air doesn't come up over a hump before hitting the valve, it's a much more direct shot.
I prefer to let Polk explain, but I'm building a 6-bolt for my 95 Talon and sticking with the 2G head for more than one reason. We'll see what the flow numbers have to say. Stock size valves, ported to the size of a 1G.
I prefer to let Polk explain, but I'm building a 6-bolt for my 95 Talon and sticking with the 2G head for more than one reason. We'll see what the flow numbers have to say. Stock size valves, ported to the size of a 1G.
Better yet, the try the dyno because it shows you what a flow bench can't.
The flow bench is an interesting benchmark but it doesn't factor in velocity.
Port shape and velocity. The 2G intake port will flow more air on the short side radius as the air doesn't come up over a hump before hitting the valve, it's a much more direct shot.
Exactly... See moxt people think that the 1g head flows more, well in an instance that is true, the reason for this are the more aggressive cams, intake manifold, and TB, but lets say you replaced these then on a 2g head, it would flow more. A 2g head with proper porting will outflow a 1g head with porting due to the port angle of the valve.
Yup, then if you really want to get serious and port it correctly take material off of the roof. Depending on how much you remove you may have to weld up the injector bosses and move the injectors back into the manifold runners.
The flow bench is an interesting benchmark but it doesn't factor in velocity.
With the right equipment you can check the velocity of ports on a flowbench. A Digital Manometer is one that helps to see where improvements could be made.
Polk
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Don Polk
Polk Performance
Hey POLK, you guys ever test the 2g head?? Those of us that support that thing are taking heat in the forums here. Obviously it's not your only job, just wondering if it will happen
With the right equipment you can check the velocity of ports on a flowbench. A Digital Manometer is one that helps to see where improvements could be made.
Polk
Are you extrapolating velocity from pressure data?
Wouldn't that require some pretty fancy modeling of port shape and area?
Flow numbers
Where are the 2G Head Flow Numbers
