If I could figure out how to post pictures. I would share some of my "300" head. Mine doesnt have as much cut away from the outer fire ring area. .060 is really too close for this set up. I would go .080 or .085 , .105 for good deshrouding and max flow.
NC remember to get notched pistons. That .528 cam will want dual springs Erson has good springs for cheap(in stock) just tell them your lift, remember we get a BIG discount.
If that is the MP cam remember to get a Doc modified oil pump as that is one of the cams that eats oil pump gears (I think).
Ceej are you running 1.78/1.56 nice port job BTW. I went with 1.78/ 1.50 as the ratio was better and they fit great.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

A reminder to everyone on the OS valves. Dont let your machine shop get lazy and sink the valves into the head. Just enough for a good seat no more.
Just my 02.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

The photos are of Fopar's head.

Heres a shot of mine. Ford valves on the left, stock on the right.
Yes, I have the smaller 300 Ford Valve



CJ

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Part of Tyrde-Browne Racing

Intresting..very intresting

Didnt know the 300 was offered in bigger and smaller sizes. Which years have the smaller ones?

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Michael Glass. Mopar stuff and some rusty Mopar stuff!
1965 Dodge Dart with 66 Valiant front clip. Other stuff...

Mine are smaller than Fopar's. I wasn't too clear on that. 1.78 and 1.54 or something to that effect.
We cut them down after the interference incident. They are also face cut to allow greater clearance. You can kind-of see that in the photo.

Sorry for the confusion.

CJ

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Part of Tyrde-Browne Racing

I am a machinist ,
Have done several slant sixes. Back in the day we used to use cut down 360 valves. Now i use cut down Chevy 305 valves. I cut the valves to around 1.84" on intake and use the 1.50 exhaust. I cut the intake valves down on my lathe and reground them on my valve machine. I do not back cut. The reason is it helps low lift but hurts high lift whenever i checked it on my flow bench. The head becaomes unstable at higer lifts sooner with a back cut valve. IT turns out there may be a real reason why they make them that way. Now to be honest I have not had my slant 6 head on my flow bench since it got sold when I sold my shop equipment BUT in extensive tests on BB Mopar heads this was what I found and I have no real good reason to believe it would be different on these /6 heads. I install SBI CAST IRON (NOT Bronze!) replacement guides which are intended for .343 stem size. I ream for just slightly above stock specs for clearance . I do a 3 angle seat and port the valve pocket straight in from the valve throat as much as possible. The further the throat is straight the better it flows as a rule of thumb. I rework the chamber so it is not shrouded and i should say I am running a huge bore since I use Chevy 194 6 clyinder pistons (STD bore). I honed the pin bores the small amount it took to get them to Slant six size. I have an early block. Late blocks at least 198 blocks will not take this much bore but mine is 1962. Stock valve retainers can be used by using the Sealed Power VK415 locks which are designed to allow chevy racers to run the larger 3/8 retainers with their .343 valve stems. (These will also work on the Ford 300 valves) I run a .545 lift cam with 241 /247 duration @ .050"and very fast ramp speed. I used the Mopar Perfomance single valve springs for up to .540 lift. The extra .005 is already figured into their fudge factor and the cam is a custom made hydraulic grind which loses traditionally .006" anyway as the hydraulic lifter soaks up the initial "umph." It appears to be working just fine. The head as described has been already run for some time with no trouble so I am satisfied with that. The new cam is the big ? but time will tell. Anyway that is my valve sizes and the story behind it
Don
Using the 300 valve is a very practical alternative. I wish I had thought of it. I should have known since when modfying 300 Ford heads we use Chevy 202.160s from the Hi perf chevy heads..
I am exploring doing a /6 head with the smaller .312 stem size. I have a valve that works . I need the time to try it. I know on the flow bench there is always a small but definate gain when the stem size is reduced. Since the /6 head can use all the flow it can get I felt it was worth the effort.

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Don