8BA valves

T

TexasT

Junior Member
Hey guys I just bought the complete valvetrain from Mac's and it came with stainless valves. The thing that concerns me is the valves from Mac's show to be the same valves for intake and exhaust, now Speedway shows two different valves for intake and exhaust, a 45degree and a 30 degree. which is correct?
 
The Speedway valves are .050" larger in diameter, but the right length. Good valves and will aid in breathing. You can read this in the description of the valves.They should be professionally installed to take advantage of their design.
 
"Right" is a sliding scale. Ford used 45º valves on both the intake and exhaust. Hot rodders discovered that you could get a bit more flow out of a 30º valve face angle on the intake. The 45º valves will theoretically last longer. So, if you want to do it like Ford did it, 45º is "right." Of course, if you use 30º valve faces, you will have to grind the valve seats to match, but I assume you will be touching up the seats regardless. Unless you have some compelling reason not to (race engine, for instance), I'd keep the 45º valves you have.
 
TexasT
Do the valves appear to have a polished or chrome stem surface? I've always seen the prices on the Macs complete valve kits but I've never purchased them. The discription is very vague. It is common to use the same valves for both intake and exhaust unless you want to change to larger head types for the intakes.

Kerby
 
The Ford ex valves are different than the intakes, They are of a two piece design with a ware sesistant stem and a stainless steel head of different materials.
 
I think it's unusual int and ex aren't different materials on flatheads unlike modern motors. If you take a magnet to the modern ones, you'll see the difference. The exhausts are very high nickel for stability.
 
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