Port/Polish of intake ports

[DanTudor57]

I went to list one of my ECZ 9425-B  manifolds and as I was taking pictures noticed that the ports on this thing were shiny. Closer inspection I discovered that the ports had been butched out and then polished. I compared them to my stock  ECZ 9425-B and sure enough, there is a good difference in the port sizing.

Does this really make a difference in performance?

I picked this up as part of a truckload LITERALLY of yblock parts many years ago. The guy selling this stuff just wanted it gone, he'd gone to a late model engine in his '57 truck. I do recall he mentioned he'd had some work done on the intake and the heads. I also recall him starting to drive off after dumping two engines and several pairs of heads and a bunch of 5 gallon buckets full of parts on my drive way.. He stopped and said something along the lines of .... " thats a good manifold, I even threw in  the rebuilt  rocker assemblies in some envelopes and the special dizzy for you.. don't leave those blocks outside they are from heavy duty trucks... Have fun, don't be like me,  I just got tired of these old engines, I just want to enjoy my truck now..."

After that day  I basically moved everything into my drive in basement garage.. Now I'm thinking I better go look at those FedEx envelopes to see whats really in there, and maybe find out what he meant by the special dizzy and the heavy duty truck engines. I found teh G heads he gave me, one of them has fully gutted and polished ports, as well as the valve areas, very polished as well, and teh other one is halfway done. I can't believe I've been sitting on this stuff for 10+ years.

So check out these pictures I took of the intake (I hope they show teh polishing okay), what do you think about this port/polish thing on an intake?

[lowrider]

That looks like what I did to my yblock manifold.  Don't know how much it helps but it has to improved it some. Yblocks aren't the best breathing engines out there. I picked up a pair of pretty rough G heads years ago and when I finally got around to using them I noticed they where both ported. Had them rebuilt and installed them on my new engine. They seem to work good but I don't have anything to compare them with.
By all means please go thru that stuff & post somes pics, maybe a few of us yblock fans can ID them. I'm sure you have something there that one of us can't live without.

[hiball3985]

Any porting on the heads and manifold will help as long as the head an manifold match. Any power gain is all relevant to what cam, rockers, compression ratio, timing etc. I would guess just using a set of ported heads and manifold on a stock engine won't gain much more then 5-10 hp at best and may actually lower the torque at lower rpm. Most modification like porting etc are made for high rpm hp gains.

As an after thought, improving the breathing on the intake side also won't gain much unless you improve the exhaust also, like headers..

[lalessi1]

I agree 100%. In my experience intakes are generally opened up like that to match ported cylinder heads. The manifold not matching the heads can cost power. If you use the manifold use the ported heads. I wouldn't expect much without the cam, headers, bumped up compression ratio, and higher rpm.

Any porting on the heads and manifold will help as long as the head an manifold match. Any power gain is all relevant to what cam, rockers, compression ratio, timing etc. I would guess just using a set of ported heads and manifold on a stock engine won't gain much more then 5-10 hp at best and may actually lower the torque at lower rpm. Most modification like porting etc are made for high rpm hp gains.

As an after thought, improving the breathing on the intake side also won't gain much unless you improve the exhaust also, like headers..

[DanTudor57]

Its gone to the epay gods now. Thank you for the feedback, using this s like to much hassle for a weekend mechanic like me. Maybe someone else can use it. I'm going to pickup the mummert intake after i sell off these  ecz 9425 intakes.

[SkylinerRon]

Porting is a voodoo science at best left to the wizards with flowbenchs.
The 57 intake is a very good manifold stock. Blocking the exhaust heat and a 1"
spacer will get you a few ponies.
The Mummert heads are the best investment for power.
Unless your engine has some other mods I'd use the iron intake and put the money
into other stuff first.
Tell us what other mods you have so far.

Ron.