Hey Joe !
Thanks for the pics and advice on porting my manifold!
I wasn't feeling confidant on opening the ports up on the drill press ,
So I went old school with a die grinder with porting burrs and sanding rolls. After 5 hours this is where I am at.
I may still get some telescoping gauges to try and get them more consistent in diameter ?
I think they might have a slight taper as they get to the bottom?
I also spent time rounding and smoothing the radius at the bottom into the ports.
 

 

Thanks for the info!!
That's just what I needed!

Would like to add that when setting the manifold up in a mill, it is not actually straight down cut of 90*, but you need to be able to set the mill/drill press up so that the new cut follows the angle of the Ford factory cut on those throttle bores.  They are at an angle, but I haven't measured it, just set up the mill so that a cutter the size of those throttle bores drops down into the bores, then lock everything in place and install the larger cutter to open up the bores.  I port the manifolds both ways, machine the bores, or hand port them because some folks balk at paying an additional $80.00 for machining them.  It is a lot of work to do by hand, and not as precise as using a cutter.  Joe-JDC

JDC

I used a cutter and drill press to cut the throttle bores, then modified them to promote the airflow turning into the ports and cartridge rolled the surfaces to keep fuel from clinging to the ports.  DO NOT try to make it a single plane intake!  You will ruin it.  You can bolt adapters to that and blend/taper them to fit your throttle body butterfly sizes.  Even though this is the Ed 255, the Ed 257 is done the same way.  Joe-JDC






JDC

No . it will be just like the pic
The manifold was originally cast for the small bore tea pot type carbs. I will use the holley style carb .It has larger bores
The adapters for using the holley carbs are tapered down to the small bore teapot style

To clarify your question?  Are you wanting to make the intake into a "single plane" intake?  If so, would that be a good idea, assuming it's for street use?..  


Paul

This is probably a question that only Ted can answer
I am modifying my edelbrock 257 for my project 292 and using adapters for the holley flange style carbs like this one from Joe Craine . I plan on going with a FITECH or holley dual injection setup.
My question is if the manifold was opened up straight down from the adapters into the manifold or if the holes were tapered? from the pic it looks to be machined from the holley adapter opening of 1 3/4" straight down? cant tell for sure?