Another 1st time port job thread

[white-lightning]

Here is what I have done so far on my 920s for my 273. I matched the intake and exhaust ports to my gaskets and smoothed the sharp edges of the spark plug bosses on one head. I plan on rolling the guide/roof of the ex. and smoothing the humps in the roof out the smoothing the whole port and bowl area with a burr and the go back with sanding rolls to really smooth it out. On the intake I plan on thinning the guide bosses and blending the bowls into the ports and smoothing with a burr to have a uniform surface. On with the pics

 

[skrews]

Good start there. You can grind out the valve cover bolt bosses in the port window like they were never there. Don't worry about breaking through, you can Loctite in some studs if you do. Also blend down the machining ridge from the top cut in to the chamber. One of the keys in getting good flow is a 3 angle valve job and decent back cut valves (usually stainless).

 

[white-lightning]

I wasn't sure about removing the valve cover bolt bosses. I just ordered longer carbides so I will do that. I already got a set of ARP valve cover studs, so I won't have to worry about that part.

 

[Cudafever]

On the exh port leave the floor alone It's to low from the factory.

Also blend down the machining ridge from the top cut in to the chamber. One of the keys in getting good flow is a 3 angle valve job and decent back cut valves (usually stainless).

And blend the bottom cut(of the 3 angle valve job) into the bowl.

 

[CultClassik]

Make sure you look at the DIY porting thread if you haven't. Looks like you've mainly worked the port windows (which wild and crazy doesn't recommend) and in the last few the big bumps in the top of the exhaust ports are still there. I completely removed mine also.

 

[white-lightning]

Yeah, so far I have only opened the port windows to match the gaskets. I have a LD4B and it was almost a perfect fit to the gasket before several minutes with a fine stone to fix the slight core shift. I only figured on working the roof of the exhaust ports and maybe the short side turn and guide bosses on the intake.

 

[CultClassik]

Yeah, so far I have only opened the port windows to match the gaskets. I have a LD4B and it was almost a perfect fit to the gasket before several minutes with a fine stone to fix the slight core shift. I only figured on working the roof of the exhaust ports and maybe the short side turn and guide bosses on the intake.

I may or may not be right, but I think the majority of the gains are in the bowl area. I had to read the porting guide about 100 times to make sure I felt like I as getting the most out of my work!