How about the valves? If the seats were cut down/modified then that would change volume up or down depending on how it was done and which valves were stuffed back in. Finding as cast factory parts is hard.They were milled .020 to clean them up.
How about the valves? If the seats were cut down/modified then that would change volume up or down depending on how it was done and which valves were stuffed back in. Finding as cast factory parts is hard.They were milled .020 to clean them up.
I have my348-409 tech portion online as a subscription based format. Please contact me at Iknowmorethanyou.com for more information and find out how to subscribe now!Sounds right going by looks. I would like to subscribe to your magazine and/or newsletter.
A head that has had multiple valve jobs where the valve heads are lower in the seat will affect CC's especially on a big valve head like a 690. The more a valve head stands proud of the roof of the combustion chamber the more it intrudes into the combustion volume making it smaller. The design of the valve head (dished vs flat) can also affect it, for example a 333 head that has had the big flat valves installed with minimal material removed to cut the seat could have equal or even less CC's that a 690 head with dished valves that has had multiple valve jobs sinking the valve in the seat. This is why published numbers for chamber volume don't really mean much except when they are fresh off the assembly line and it is important to measure your actual volume when targeting a specific CR and ordering pistons. Add in the fact that after all these years there is a good possibility that the heads have been clean up milled during previous valve jobs. But assuming 2 heads that are virgin I would agree with Randy that the 333 head would give slightly lower CR since there is an ~8 cc difference.How about the valves? If the seats were cut down/modified then that would change volume up or down depending on how it was done and which valves were stuffed back in. Finding as cast factory parts is hard.
I was hoping to get these heads I have measured before Tri-State race here in Iowa but the kids flag football schedule is digging into my play time. So many questions on this topic to keep the information/understanding consistent. Again, a big thank you to all of you contributing to the information/knowledge. Some of us young guys want as much as we can gather so we don't loose this information.A head that has had multiple valve jobs where the valve heads are lower in the seat will affect CC's especially on a big valve head like a 690. The more a valve head stands proud of the roof of the combustion chamber the more it intrudes into the combustion volume making it smaller. The design of the valve head (dished vs flat) can also affect it, for example a 333 head that has had the big flat valves installed with minimal material removed to cut the seat could have equal or even less CC's that a 690 head with dished valves that has had multiple valve jobs sinking the valve in the seat. This is why published numbers for chamber volume don't really mean much except when they are fresh off the assembly line and it is important to measure your actual volume when targeting a specific CR and ordering pistons. Add in the fact that after all these years there is a good possibility that the heads have been clean up milled during previous valve jobs. But assuming 2 heads that are virgin I would agree with Randy that the 333 head would give slightly lower CR since there is an ~8 cc difference.
The 348-409 section was very informative. Thank you. Why is the rest of the site so STD focused?I have my348-409 tech portion online as a subscription based format. Please contact me at Iknowmorethanyou.com for more information and find out how to subscribe now!
It’s on the dark web due to the prolific images of transgender pornography.So where/what is the "iknowmorethanyou 348-409" site? When I tried to google it, it went to this forum.
Jeff