Quick Question. Header gaskets and oil pump

[K85 Octane]

I have this system.

The heads are '91. This system works perfect, so do that gaskets. I'm now taking the headers off to get coated and need new gaskets. I want some Percy's aluminum gaskets, but not sure if I need oval, round, or D port:

Which do I need?

Also, I'm looking for an oil pump, to replace my high volume one. With a regular volume pump and mild engine, should I get a 5/8" or 3/4" pickup? I'll be tig welding it on

Thanks!!!
'79 400, stock pan

 

[CGT80]

It depends on the shape of the ports on your heads and headers. My edelbrock heads with extensive porting work have ports that are almost square. (I don't remember what the shape was like before porting.) I bought the square sbc gaskets for my 406 and they mated up nicely to the heads but did not line up well with the flange surface on the thorley tri y headers. The flanges were a round shape. The primary's are 1 5/8 inch and were smaller than the square gaskets anyway, so the extra open area in the corners wouldn't really help the flow and would have caused a leak.

The percys sbc round worked well on mine. They seem to have sealed well. I have 2500 miles on my engine now. I did find a couple spots where it looks like the header tubes were not welded completely to the flange. I have a couple black spots on the ceramic coating between the tube and flange on the outside of the headers. I didn't see that before on the chrome or after the headers turned colors and started to surface rust.

Mine is also a 79 and the oil pan and timing cover are stock. That's about all that's left on my engine that is even close to stock. I think my engine builder used the melling 55 pump but i don't know what size the pickup is. I would have to check the build sheet to see if it is hv or not. It is not high pressure, but my engine will run up to 95psi oil when cold on 30 wt and runs down the freeway at operating temp at 50psi, it does drop to 17-18 psi at idle when its warmed up. At 700-800 rpm it jumps back up. I could look up the actual part number if you want.

I have read about the oil pumps being a thinner casting on the new standard series pumps. some have failed but I don't know if the problem has been solved or if it still happens. I picked my engine up the day before I read about that and haven't bothered to ask my builder what his experience was. I do watch my oil pressure and head temp like a hawk though.

 

[K85 Octane]

I think I'll get the round gaskets. They seem to only have 1.5" though and I know the headers are 1.650. Interesting trouble I'm having, then again I'm not to knowledgeable with this stuff.