I think I straight up ruined a 47 head from my 69 350. I didn't know what I was doing and shouldn't have been doing it. I attached a pic of one bowl, all 4 look like this. I got too aggressive around the valve guide and the wall thickness to the coolant passage is probably too thin for me to be comfortable installing this head.
Now I need replacement heads and I have a couple questions on what would be a good fit. I've seen the charts online of the different head castings, years, fit, chamber size, etc, but it's unclear to me what heads could be a good fit.
As seen in the other picture, my block is machined for the big valves.
My specific questions are these...
1. Do the pistons have the correct relief cuts for big valves? See picture. I've been told by one Pontiac Head specialist that the reliefs are for big valves and I must use big valve heads.
2. I have opportunity to buy either some 48 or 62 heads, both sets with date codes from 69. Both sets came off of 400 blocks. Both appear to have screw in studs. Are either of these heads a good fit for my 350 with stock bore, stroke, etc.? I've read as much as I can find but it makes my head spin.
All I want out of a set of heads right now is to get my 350 running again. I'm not looking for heads to be a magic performance upgrade. I actually liked the performance with the 47 heads well enough. It has been converted to a 4 barrel intake and was running fine when I pulled the engine for a ring and bearing refresh.
Can anyone say if the 350 and the 350HO used the same pistons, or did the HO have different valve relief. I have a block that will handle big valve heads but I cannot confirm that the pistons I have have the correct relief for big valves.
