J head porting

EL5DEMON340 said
This would be about the 10th mopar head I have ported, bb and SB, Harley Davidson head, jap bike heads, some flathead old school mini bike stuff!! Why would I need to cut the bigger seat right now when I’m working on the guide? I will probably do one port and have it flowed to see if it’s going to be good. After 40 years of hot rodding everything I own I think I have a good handle on things. I have a pretty good reputation on this site for giving sound advice and sharing my builds and mods. And a quick small block Demon. But I will take your advice along with others because I know I don’t know it all and am always learning.

Because I’m a nice guy, I’ll tell you EXACTLY why I said to start with the valve job.

Because thats where the most power is. Because it establishes the throat size. Because it is the biggest factor in how the rest of the port is shaped.

I’m all for working the guide but for the amount of time and effort spent the most power to be had is in the valve job. You’ll get very little in return working the guide boss (although I suggest you do do it, just not at first) compared to getting the valve job correct.