Hi All,

Now before anyone jumps in with "**** job" or the likes, this is my very first attempt at porting heads, as well as using the rotary tool and carbide bits etc, and I have prepared for the inevitability that these heads may get junked as a result of this, but everyone has to start somewhere and I'm just looking for some constructive criticism and guidance more than anything.

I'm building my first ls1 5.7L with stock bottom end, VCM710 cam, Holley sniper EFI intake, along with some larger injectors, 4L60E with 3000 stall and putting it in my 85 TransAM to replace a 400SBC x24 converted motor that loves to leak oil wherever it goes.
I'll posbbily put a twin turbo setup with low boost in at a later date, but the cam I've selected usually works well with a set of 243 heads or ported 241a.

I'm in Australia and for some reason there is a huge shortage of 241 and 243 heads 2nd hand, so my 2 viable options at the moment are to port the 241 heads I have, or buy a set of Speedmaster "CNC" 243 style heads for $AUD1200 and use as is. The reviews on these are very hit and miss, but I would assume they'd be at least better than stock 241 heads.
So I've watched all the YouTube videos I could for the 241 heads and decided to give it a go myself.
The basics I'm working on is to:

*Open up the exhaust ports by matching them to the gaskets (top half only, not touching the head floor)
*Clean up any rough spots and smooth out the walls
*Remove swirl port from intake valve area
*Bullet the valve guides
*Clean up and blend the valve seat material to get rid of any lip
*and smooth everything out in the bowl

Once then rough cut is done I'll finish off the intake area with 80grit rolls and then smooth out the exhaust areas as much as I can, not to polished level but smooth.

I've heard in the videos people talking about calculating out how much of the bowl to cut out in relation to the valve size etc, but I wasn't looking to get a 300cfm flowing head from this, and wasn't too interested in trying for massive gains given its my first time, just to get as much flow as I can with as little work as is needed to make an improvement in the engine performance.
From what I can tell the most important thing is to try and keep the amount of material moved and the shape of everything as consistent as possible from cylinder to cylinder, so I'll try my best to do that.

That said, I'l post the pics up as I go and see what everyone thinks and can point out IF i've done anything right, and I guess more importantly, what I've done wrong and if there's a way to fix it.
This is the first port with the first cut just to remove the material around the valve guide and try to take out the swirl port. I'm not sure if this is enough or if I have to remove more to completely smooth it out?



This one's the next one untouched, just for reference.

 

Not relevant now but I have Higgins ported 241 and they (plus new cats) took me from 258 rwkw to 296 rwkw with a very a tiny cam and restrictive exhaust system. I think it would have hit over 300 rwkw with bigger headers, basically stock. One of my best mods.

https://www.lsxperformanceparts.com....-241-castings/

 

Yeah they are on my list. I actually bought my cam and most of the other gear going into the motor from them so they quoted me a good deal on porting if I supply the 241 heads for just over $950, and they'll install the new springs and set everything up at the same time which is good.
My only problem was that I had already started opening the exhaust ports up and wasn't sure if I'd gone too far with them. I've found a set of 241 heads locally and waiting to hear back if I can pick them up tomorrow morning. If so I'll send those in and get the higgins porting done, but I'll still work on these if for nothing else but practice.


What cam did you put in?

 

A ported 241 head has some serious potential.

 

Good stuff. Higgins is a bit of a genius IMO. Very helpful guy too. This was my old combo, there's a thread happening about the issues with my new combo but it was a Comp 214/217 .600/.587 112+4.

 

Hello, I would not gasket match the exhaust. Same reason headers plates holes are larger than the ports. It is late and I can not remember the term--"reversion" ??, if you have any back flow pulses the extra meat stops it from going into the head. Port it out the same size as the rest of the port but do not funnel it at the gasket.
Hope that helps.

 

Ok, so I got another set of heads and they are being shipped off for Higgins CNC porting and assembly, so this set is a free for all.
I'm going to get stuck into them this week and see what I end up with.

I've got the carbide burrs to do some of the heavy removal, but the can the 80grit sanding rolls still take out material?
I ask because the burrs I have are only short, whereas the sanding roll bits I have are 6" to reach right into the ports.

 

Yes the sandpaper rolls will take out material. Of course not as much as a burr will, plus the sandpaper will wear out/ fill up with aluminum rather fast.