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Tue Mar 04, 2014 9:36 pm

I am almost done building a 2180 cc motor and want to install 40x35.5 big valve heads. What or which is the best one out there?I have heard 043 and cb performance. Your thoughts?

Tue Mar 04, 2014 9:37 pm

What cam??

Tue Mar 04, 2014 9:41 pm

In my case a scat c-35. A friend is building a 1835,stock with nothing special and asked me the other day the question. I did not know what to tell him. Hence the topic.

Tue Mar 04, 2014 9:50 pm

Use RevMaster 40x35 CNC ported or CB Los Panchitos. They'll both flow more than well enough for that cc and cam.

Tue Mar 04, 2014 10:13 pm

But you'll need to have the step machined out, same goes for other choices such as Mofoco 042 (but if you are a Samba member Roy will do you a deal on the step apparently.)

It's a bit of a "how long is a piece of string" question, a lot depends on what you want from the engine, your cam, carburation, exhaust. The great thing about DRD (who sells the Revmaster,) Mofoco or Tims is you can actually ask them and get some honest advice - much better than just picking from a catalogue if you don't have a world of experience (posting on forums doesn't count as experience in this regard.)

Tue Mar 04, 2014 10:59 pm

the porting is way more important than the valve size, FWIW.

Wed Mar 05, 2014 1:04 am

I'd go for a good set of ported heads with a good chamber volume without step, if you remove the step in a los panchitos head, you won't have enough chamber volume anymore.

Wed Mar 05, 2014 1:44 am

Yes, and a good porting job beats an oversized one. I found 044 and 042 pretty good out of the box, haven't tried the Revmaster yet (they just haven't suited anything I've built.)

If you go ported it opens up a whole other can of worms. I'm still a bit wary of the cheap CNC ported heads myself. Looked really good at first, but I'll be buying unported or hand ported next build.

Wed Mar 05, 2014 7:09 am

You know one of the best parts about a Mofoco 042 head? It comes ported from the foundry!! Yes, you read that correctly. Since we designed the head and own the mold, we have them cast with the correct size port already in the head. No need for "CNC porting" You know what's even better? With additional port work, you can increase the flow by as much as 60 CFM.(Not that I think you need to for your application)

For your application, there are a few different heads you can choose from. Obviously, I think the Mofoco 042's are your best bang for the buck. And our heads are Made 100% in the USA with as many many Made in the USA parts as possible.

As for the step, I am on the side that it makes absolutely zero difference, as long as the C/R is set up correctly. If you want to stand on the other side of the fence, I will not be offended. I can machine the heads for no step, same price.

http://www.mofoco.com/item/MOFOCO_042_BIG_VALVE_CYLINDER_HEAD/235/c52

Wed Mar 05, 2014 8:11 am

roy@mofoco.com wrote:

For your application, there are a few different heads you can choose from. Obviously, I think the Mofoco 042's are your best bang for the buck. And our heads are Made 100% in the USA with as many many Made in the USA parts as possible.

http://www.mofoco.com/item/MOFOCO_042_BIG_VALVE_CYLINDER_HEAD/235/c52

I have visited you site many times....looked at you heads...and wonder why you machine the spark plugs at 14mm in the get go :?:

and charge an extra $25 per head and up to 6 weeks for the 12mm plugs, when your heads are cast and you are drilling(machining) the spark plug hole(just a blank at that time)....just as easy(and I am sure you will correct me) to drill 12 mm, which gives one more aluminum meat between the valve seats and the plug holes....same holds true of your 050 heads..... (biggest failure area on 1/2" reach sparkplug heads....spark plug hole to the valve seat) I cannot attest if this is true on the 3/4 reach plug hole to the seat.....you can inform me on this

I would drop the 14mm plug holes and go to 12mm in all of your heads.....and charge extra for the 14mm for the anal builders.

My best VW Buddy, just opened up an engine 1776 that has about 60K on it, has brand x heads with 3/4 reach 12mm plugs holes....42x37.5...
heads had been hemi-cut(old school, but was popular at the time of the initial build) had single HD springs, running Engle 110 ....this engine was built about 18-20 years ago.....only reason he opened up....cut heads and case for 94s, and going with a 74 stroke.....and turbo....he was running dual carbs 40s. There was, and this is hard to believe....literally no carbon build up in the combustion changers on these heads.....car was driven in the Phoenix area (hot climate) for those 60K miles

I will be rebuilding these heads.....the guides are not that worn, but we are replacing anyway, cutting the boss for dual springs(after new guides are installed).....and I will be doing a 3 angle on the seats with proper width and position on the valves.

bottom line on best head for the $$ is the most cost effective head that one can afford, that has all of the features and specs for that individual build.

Roy do not get me wrong, I think you produce a very good product, both the 042 and the 050 heads.....and I will be buying some heads in the near future....and still shopping and comparing.....but I do not want to pay extra for 12mm plug holes for what I think should be standard and or a choice no $$ option for the base cost of your heads.

Wed Mar 05, 2014 8:14 am

For that size motor, you really mean 42 x 37 size valves, don't you?

Wed Mar 05, 2014 11:41 am

Many to choose from

My vote is for the RevMaster 42x37 either unported so you can save cash and do the porting yourself or the CNC version which looks its between the L5 and L6

http://www.thesamba.com/vw/classifieds/detail.php?id=1490829

If you want the 40x35 the AA 500-420 is hard to beat. Extra casting around the ports and improved 60cc combustion chamber

Wed Mar 05, 2014 12:03 pm

I have looked at this chart many times....
I wish all of the listed heads had the CFM data calculated for a complete comparison .....still missing a few flow numbers

Wed Mar 05, 2014 12:15 pm

rockurob wrote: I have looked at this chart many times....
I wish all of the listed heads had the CFM data calculated for a complete comparison .....still missing a few flow numbers

Me too. It seems some vendors do not want the public to compare their products with others.

MOFOCO said he would get me the numbers for his heads but still waiting.

The main thing I did was to convert all flow numbers to 25" so that comparisons are equal.

Wed Mar 05, 2014 12:24 pm

yup and another flow chart for the mofo's at the same lifts as the others,it's listed at .450 lift. I cant seem to find my flow sheet from mine when I did them to add to this.I do know they were about 2 cfm more than what was listed. heads used to be flowed at a lift squared to the valve/stem squared,now days that usualy isant done,just an lift in mulitiples of .100,witch also makes it hard to compare stuff,along with diferent flow rates&flow rates that are not listed so you realy have no clue as to what they are comparativly.
I dont know how much roy has changed his 042 head mold but mine were not ported or even maximized for flow, just mainly a biger port.still it's a great head that has plenty of room for even more improvement,flows more than most out of the box,and more than some that have been ported. With everything you can do you cant shrink the ex port very easely or raise the floor like almost ALL acvw heads need.

with all the foundrys in the usa I see no reason for over seas heads at all.other than adding $$$ to importer&vender pockets. did the head prices drop when the china heads hit the shores of california????????I seem to remember the prices cb was selling the oe vw head just prior to the china head influx...do you?? less than the china stuff.

Wed Mar 05, 2014 12:25 pm

AlteWagen wrote: rockurob wrote: I have looked at this chart many times....
I wish all of the listed heads had the CFM data calculated for a complete comparison .....still missing a few flow numbers

Me too. It seems some vendors do not want the public to compare their products with others.

MOFOCO said he would get me the numbers for his heads but still waiting.

The main thing I did was to convert all flow numbers to 25" so that comparisons are equal.

Thanks for this effort....
I am also interested in MOFOCO's numbers
(sort of like cam numbers....i want to know a little more
than duration and lift....I want the IO, IC, EO, EC numbers to
really compare....like numbers off the cam card info)

I will be buying a pair of heads in the near future.....and will reference
your chart in my decision

Wed Mar 05, 2014 12:53 pm

what I find most interesting is the relationship between port cc and flow numbers. Take for instance the CB Panchito, Ultra mag and Tims SII, all flow similar numbers but the port volumes are HUGELY different at 66cc for the panchito vs 75cc for the SII, and 82cc for the ultra mag. And to think that the Panchito is still using 40mm intakes while the others are 42mm.

I hope Roy comes through with the numbers like he said he would.

Wed Mar 05, 2014 2:04 pm

Yes, the chart would be great if it were more accurate. Unfortunately it is all gleaned from the internet and therefore often incorrect. One figure that might be useful is the port volume, but there are a number of instances where it is supplied but clearly incorrect. I suspect someone has a figure for an unmachined head which has been copied over to the ported unit. I'm not trying to criticise Altewagen, the only way to get an accurate and unbiased chart would be if an independent person were to measure and test all the heads.

Roy has already stated yet again he will remove the step at no charge for Samba members above. As to wait times, they are machining the heads in house and there are logistics to be considered. Unfortunately Americans cost more than Mexicans or Chinese so he would have to maximise their utilisation. As to the 12mm plug - why are you set on it where it is not needed? Sure they can work as well, but it is far easier to get the plug you want in 14mm. A 12mm plug with extended nose in a long reach can be hard to find with both the electrode style and quality make you want.

Wed Mar 05, 2014 2:07 pm

Why would you pre-cast in porting into your heads? Isn't porting based off of the application? Surely all heads can not be created equal to fit any application.

Wed Mar 05, 2014 2:15 pm

unless flow #s are done on the same flow bench you can't fairly compare them anyways, at least if you want accurate comparisons. Advertised #s are for LIGHT reference only, and should not be used to make head purchasing decisions.

And then you have the issue that most aren't even aware of, which is that

1) flow #s are done at steady state, and running 4 stroke engine are anything but steady state.

2) flow #s only measure air, they do not measure an air and fuel mixture. Poor performing ports can flow air well, but wet out when they are flowing fuel and air. Good performance in flow #s CAN mean good performance on a running engine, but not necessarily.