Porting 243 heads
I don't have a flow bench so I don't have any first hand experience. After watching countless video's on porting 243 heads I pretty much came to the conclusion that there isn't anything to be gained by opening the exhaust port.
Last edited by LLLosingit; Apr 10, 2020 at 07:41 PM.
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243 cylinder head that I raised the roof. This set of 243 heads will go on a C5 and should wake it up nicely. The pictures is not the best still it should show that I raised the roof and still left plenty of material.
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So what gasket is this guy using? Basically trying to do what's at 3:50. My gasket seems giant compared to his? Thanks
https://youtu.be/JAeSqBU6OJI
https://youtu.be/JAeSqBU6OJI
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It's actually easier to get better results as a percentage on the exhaust ! Stock port is going to flow low 180s ........ good hand port 210 cfm when compared to top cnc programs !
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I'd have to search for the video, I'm not saying there aren't gains to be had overall. The video I watched they did step by step port work and put it on the bench with each change. Bowl blend was a good gain as was working the swirl ramp and guides on both intake and exhaust, Good gains with a good valve job and back cut valves, Unshrouding the valves and port matching were smaller gains but still an improvement if done correctly and can actually hurt flow if taken to far or done incorrectly.
I'd have to search for the video, I'm not saying there aren't gains to be had overall. The video I watched they did step by step port work and put it on the bench with each change. Bowl blend was a good gain as was working the swirl ramp and guides on both intake and exhaust, Good gains with a good valve job and back cut valves, Unshrouding the valves and port matching were smaller gains but still an improvement if done correctly and can actually hurt flow if taken to far or done incorrectly.
I would think just knocking off the rough, raising the roof some and smoothing the exhaust chambers would improve performance. Some good videos on the subject from StreetKillz Video Chronicles
Remove lumps and bumps, size reduce obstructions like the guide boss, blend the bowl to valve seat and if your really feeling it, blend the valve seat to the chamber so the transition there is seamless. Don’t make the port bigger, not really necessary. Most bang for the buck is bowl work.
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If you want to know the theory behind head porting David Vizard has a few videos and some books on the subject. On Youtube HeadflowInc and David Vizard have the most useful information as to the reasons you should make certain mods to cylinder heads.
I would not recommend his videos as guide for a novice for a number of reasons .His terminology is not accurate , there is no real benefit in removing the hump behind the valve guide boss if a novice starts digging there he could break through real quick and so on !