Would anyone benefit from a ported Intake manifold? Im thinking of porting mine but if Im not going to see any gains then why bother....

I already have the ported Plenum...and may be getting some bigger runners...


I have heard of HP loss from ported manifolds? T/F?

I wanna keep my low end...well, what little I have with the 305..

 

I siamese ported the intake on my car and it lost ALL low end power. I had a 2400 stall and it caused the car to stumble coming off the line. I actually had to buy a used intake off this site to replace mine. Then once I went to the 3800 converter, I put the siamesed intake back on. The siamesed intake flows much better up high, but really does a number on the low end grunt.

 

What about porting just the plenum and runners? Would the same thing happen?

 

For the 305, just port the plenum (egr walls, radius the outlet holes, etc) Gasket match the runners to the plemum and intake base. Remove any large casting flash in the intake ports and plenum. This is about the extent of what you want to do with a stock 305 setup. If you go opening up the ports too much you will loose air velocity and as a result, power.

 

Does removing the CASTING MARKS really make that big a deal?

I got the 305 and am in the process of installing a set of headers and Im going to replace my leaking water pump soOOOO I figured I would replace the PEANUT CAM.....SoOOO while I have the intake off I was thinking of having it ported.....but I guess I just leave it alone.

I have a PORTED plenum and the RAM AIR boxes...I have just read so much about porting ...but it seems sometimes it hurt more than helps....


and the SoOOOO's keep growing......LOL

 

would a hi flow aftermarket base and runners have this same effect??

 

It can, depending on how big they are and where. just removinh obstructions in the air flow path will only help the engine to breathe better. When you start enlarging ports and runners is where you run into flow problems with the smaller cid engines.