Home 241 head Porting
I did the same intake port work to a spare #706 head a couple months ago, but haven't had it flowed yet. I took a different approach in the exhaust long side, near the guide boss.
Your upper-lift intake flow gain gives me hope.
Thank you for sharing.
Your upper-lift intake flow gain gives me hope.
Thank you for sharing.
Last edited by Isolde; Oct 5, 2010 at 08:35 PM. Reason: typo
Thread Starter
Joined: Jan 2008
Posts: 597
Likes: 9
From: Tequesta, FL
I did these heads for an engine build that I'm still working on. When its done and I get some numbers as far as rwhp and track times I will update this thread with all the specifics. I would port another set but honestly for the amount of time that it took I'd have to charge a lot and it may not be worth it for someone to pay a joe schmoe on ls1tech that amount of money to port heads.
Second time i've read through this thread, great job. Im picking up some 862's to work on this weekend. I need to finish setting up my new tig and learn aluminum welding first.
Where the heads you used as an example a set you actually had on hand to look at, or just pictures? If its pics would you mind sending me them?
Where the heads you used as an example a set you actually had on hand to look at, or just pictures? If its pics would you mind sending me them?
I am in the process of doing the same thing but I have one ( ? ). Would I be better off doing this to stock 99 heads ( 853's ) or some 241's? I have heard the 241's are a little better out tha box but not sure if after porting they would still be better or not? The 853 would be free castings and the 241's I can get complete with lower miles for $40. thanks.
Thread Starter
Joined: Jan 2008
Posts: 597
Likes: 9
From: Tequesta, FL
I am in the process of doing the same thing but I have one ( ? ). Would I be better off doing this to stock 99 heads ( 853's ) or some 241's? I have heard the 241's are a little better out tha box but not sure if after porting they would still be better or not? The 853 would be free castings and the 241's I can get complete with lower miles for $40. thanks.
I would get both sets of heads. Practice on the 853's first since they are free, then use the 241's to do the porting on (if theyre low miles and only 40 bucks thats a DEAL). You will need to practice with the different bits to see how much they take out and to just really get a feel for how the heads are going to port.
I was really happy with this set of 241s I did with the stock valves and valvejob I blended.
https://ls1tech.com/forums/generatio...d-heads-2.html
https://ls1tech.com/forums/generatio...d-heads-2.html
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Verdad Gallardo Thread Starter
Joined: Jan 2008
Posts: 597
Likes: 9
From: Tequesta, FL
Actually, the 853 are on the car and its my daily driver right now. I was wanting to do the 241's and then swap em out with minimal down time but if the 853's were really any better then Id go that route after practicing on the 241's, but Im on the same page as you are about practicing. I have home ported many motorcycle type heads before with good results and hopefully the cathedral ports on these heads act the same way as the bike heads, tall and narrow, should be close. Im also kinda curious about cutting into the thread pocket for the rocker studs, seems like that could weaken the torque load of the threads maybe enough to cause stripped threads? Seems like theres someone on here with this problem with patriot heads, any correlation between the two possibly???
Thread Starter
Joined: Jan 2008
Posts: 597
Likes: 9
From: Tequesta, FL
I did get the motor together but have not been on here much in the last 5 years. With a TR224/224 .563.563 112LSA and these heads, the car put down 375hp/380tq on a mustang dyno. I was honestly hoping for more but it drives great, good midrange and pulls hard up top. The car was trapping in the low teens when i used to go to the track. I dont think I would ever port another set of 241's because it seems the gains are minimal. If any one is thinking about it I would recommend going straight to a set of 243's and dont waste time porting 241's.
I want to say congrats on the port work! I am a little surprised you didn't get bashed. I ported my 799's at home. I had a bunch of guys who made it sound like I was nuts, and working on a 1 off set of billet heads or something. LOL. I personally think it's well worth doing even minor clean up and learning to do it yourself. Great Job!
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
Plus EVERY port will be machined EXACTLY identical. Unless you have hand-ported heads for a few years, there will be inconsistencies between ports on a hand-ported head.
i'd be worried less about inconsistencies, you can probably come really close with equal cross sections and port volumes if you take your time, measure everything, and possibly develop your own volume-measuring rig.
My thing is this: a CnC program already takes a proven port shape and cuts it out of your ports, which is better than what i can do even if i'm careful, and then the valve cut plays a large role in flow, and i can't do this myself. i would spend tons of time porting and making sure everything matched, only to pay money to have the head machined anyway, to still have something that is not as good as your run of the mill CnC job.
So, i say screw it. Unless you're dying for a DYI project, send them in. It would be a cool project to post about, but most people want results. Then you know what you're getting for sure, and aren't taking a ton of time out to do it. It's bad enough taking the time out to swap heads/cam/lifters/oil pump/timming system etc etc etc...
My thing is this: a CnC program already takes a proven port shape and cuts it out of your ports, which is better than what i can do even if i'm careful, and then the valve cut plays a large role in flow, and i can't do this myself. i would spend tons of time porting and making sure everything matched, only to pay money to have the head machined anyway, to still have something that is not as good as your run of the mill CnC job.
So, i say screw it. Unless you're dying for a DYI project, send them in. It would be a cool project to post about, but most people want results. Then you know what you're getting for sure, and aren't taking a ton of time out to do it. It's bad enough taking the time out to swap heads/cam/lifters/oil pump/timming system etc etc etc...
It could come down to level of interest in the diy aspect, or to simple economics. Several threads on porting suggest that 80% of gains come from valve work, so the heads would be sent out in any case., $750 for consistent cnc work versus hand porting at basically $25 an hour (saved) diy can become an economic calculus if the 80% gain rule is fact. With careful work, inconsistencies from cylinder to cylinder probably won't be apparent in a less than max effort build. The OP has obvious skills that may not be universally shared by the rest of us, and there are material costs to home porting, but 750 bucks saved is still 750 bucks.
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
NOT to sound two-faced, there is something to be said about the above. IF a guy has a good steady hand with the grinder, a lot can be done around the bowl area, especially just getting rid of the step and any ridge. BIG gains for a little work by one's self.
So for the ultimate, get the CNC job done. For GOOD gains, clean up the bowl/throat area yourself.
So for the ultimate, get the CNC job done. For GOOD gains, clean up the bowl/throat area yourself.
Thread Starter
Joined: Jan 2008
Posts: 597
Likes: 9
From: Tequesta, FL
It could come down to level of interest in the diy aspect, or to simple economics. Several threads on porting suggest that 80% of gains come from valve work, so the heads would be sent out in any case., $750 for consistent cnc work versus hand porting at basically $25 an hour (saved) diy can become an economic calculus if the 80% gain rule is fact. With careful work, inconsistencies from cylinder to cylinder probably won't be apparent in a less than max effort build. The OP has obvious skills that may not be universally shared by the rest of us, and there are material costs to home porting, but 750 bucks saved is still 750 bucks.