OK..this is a little long..but i will try to explain it.i'm really a pontiac guy..i have some Oldsmobiles..but...want to run this by a few smart guys...

outside the box idea/theory...of course its my theory...not a proven one..

so..i was wondering...i know BB heads will go on a small block..but the ports are tall and you need to make sure the intake has enough mass to work...and everyone says an edelbrock is the way to go...may need a little welding and or grinding (cant remember which)...to match the roof of the port..this is what ive heard and read

so just thinking out loud...since olds motors are considered "square"...and if you mill lets say .060 you take .060 off the intake...no weird angles..

so...will this work? im not an engineer or machinist...but i dont understand all i know about it...

im making up a number here...i dont have the chmber sizes in front of me right now..

lets say i take and mill the head .090 on the chamber side...leave the intake alone except oblong the holes....fill the floor of the head runner with epoxy..mill the bottom of the intake not the port side...will it work? will the intake bolt on?...does the angles stay the same..except the intake rides higher on the head surface...i know the bolt holes will move...

if not...why..explain what else i need..to me...over simplified..if the port are so tall...moving the head surface down, the intake sits higher... by doing this..the bolt holes move too...so theres plenty of room to oblong the bolt holes on an intake....can it be this simple? i have some BB heads...i have a relative that owns a machine shop...so theres no out of pocket to experiment with...

on other makes...raising the floor of the runner helps..it get the valve angle shot better..and also increases port velocity...

thinking this may be a cheap way to put decent heads on a 403...

just thinking out loud....i am not easily made mad..i'm just trying to understand it...id like a few opinions...becasue i think it may work..

 

My understanding is equal intake to head milling. Many have used the BB heads on 350 and 403's. Some have done exactly what you are talking about with the intake bolt holes so the intake ports sit at the top of the port opening in the head. You also must use the Victor or RPM intakes or weld the top to cover the larger port.

 

It's not just the ports that need to line up, but the bolt holes, so whatever milling you do to the heads has to be matched with the intake to line everything back up.
A performer RPM was designed with the extra material so that you can run a BBO head on a SBO. The ports have enough material to open them up to port match to an intake gasket so that there won't be any reversion at the joint between the head and intake.
If you use a factory head you will need to open up the head bolt holes from 7/16" to 1/2" for your 403 as well.