I have a head that I decided to port and polish. The local machine shop did the port work but it's rough so I'm cleaning it up. Before I install it I am going to have it flow benched to make sure it's not worse than stock🥴.

Does anyone have numbers on a stock mcs head? Would be great to know numbers on jcw, cos worth, rmw, etc.

I'll gladly post my numbers after I get them. I just wanted a comparison to at least stock without having to pull off my current head.

Thanks everyone. I did look through threads, but only found one set of numbers for a head is never heard of.
Brad

 

Even if you found the numbers you're looking for, there's no guarantee the machine shop could replicate them on a stock head - there's too many variables (machine calibration, atmospheric pressure, temperature, etc.).
The best way to compare would be to pull your stock head and bring it to them to test side by side with the ported one.
Sorry it's not the answer you want.

 

I know you're right, especially if you're expecting comparative results. I'm just looking for some sort of numbers to use as a rough baseline. As an example I have no idea if the flow numbers I have on my ported head are better than stock. I do wish there were a way to do comparisons from head to head on different flow benches, but it is what it is. And it sounds like flow benches are far more varied than dynos.

 

Had a great talk with Bob at Stiegmeyer today. I've got a visit scheduled next Wednesday to have Bob flow my stock head and my ported head. I know very little about flow bench testing, but Bob seemed excited. He says he's interested in putting it all together to see if it gives him more ideas for modding our m45 superchargers. I'm looking forward to seeing what he comes up with.

I'll also be able to know for sure if my local machine shop did a decent job porting my head. I've got my fingers crossed and I'm going to see some decent results. Stay tuned.

 

Attached are pics of the stock head and my mildly ported one. All that was done to the intake side was to clean the casting flaws, no reshaping or enlarging. From what I've read the intake side flows pretty well so didn't mess too much there.

Opened the exhaust side up and polished it the best that I could. I didn't try to make this a super head. Just trying to get some extra out of it.

If you look closely at the stock head which came off of my old motor you'll see the outline of the exhaust gasket. It's crazy how much material needs to be removed to gasket match!!!




Ported head

 

Stock head

 

Interesting, but what have you done to increase air density?

 

On the road right now but I'll get back with bowl and throat% changes. I hope that's what you're asking. I'm an amateur at this stuff so I'll be glad to listen if anyone has stuff to add.

Valves are slightly oversized as well fwiw. Not the big super tech valves but 1.5mm and .5mm oversized.

 

I've dealt with Bob at Stiegemeier. He is really easy to talk with and very knowledgeable. I ended up with one of his ported M45's on my car and I am very happy with it so far.

 

Met with Bob at Stiegemeier yesterday. Lots of little issues like spark plug tubes (how do you remove them?), head size, etc made it frustrating and time consuming. Bob usually does American v8 motors so setting up the superflo bench for it little 4 valve head was a hassle for him. He was very nice and knowledgeable, but it took 8.5 hours and I had to drive 4 hours each way. Long day!

Anyway, the good news is that I have numbers.
Stock head intake:
.100 lift 79cfm
.200. 114
.300. 120
.400. 189
.500. 191

Ported head intake:
.100. 111cfm. +29%
.200. 177. +36%
.300. 207. +57%
.400. 210. +10%
.500. 216. +11%

Stock head exhaust:
.100. 69cfm
.200. 108
.300. 117
.400. 118
.500. 119

Ported head exhaust:
.100. 81cfm. +21%
.200. 120. +10%
.300. 145. +19%
.400. 155. +24%
.500. 165. +28%

The difference was pretty significant. Bob didn't really believe them and tested the ported head multiple times, making adjustments and shifting the jig to make sure there wasn't a leak. The numbers were consistent so I think they are pretty reliable.

Looks like my local machinist did a pretty good job on this head. It seems like it'll be worth putting on my new motor.

I spent the time and money to have a comparison to a stock head on the same bench on the same day with the same operator. I think the numbers are at least reliable between the heads.

I had a set of stock head flow numbers that I found somewhere. Comparing those numbers to our measured stock head numbers yesterday were within a few CFM so I think Bob wasn't to far off of at all.

I hope this helps someone else out there. I'll post in my other thread about the progress getting the car back together.

SOMEBODY LINK ME HOW TO REMOVE SPARK PLUG TUBES!!!

 

Sweet! Good work.