As you can see from the attached photo, my car has crankcase breathers installed (blue hoses.) I've been all over the WWW, and it seems that this setup is the rare, not the norm, with our Spyders.
I've just ordered some Porsche-branded valve covers, and I'd really prefer not to drill the sides of them to reinstall this rig.
Still, if it's the best way to go, I'll do so.
What do you experts say? Am I going to miss these if I remove them?
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IMHO, the answer is no you don't absolutely need the extra crank case ventilation, but it is advisable to have it especially if you plan to run your revs past 4500 regularly which I hope you do. The extra crankcase vents give you a little more HP and most importantly help keep oil leaks to a minimum. Without the extra vents the high crankcase pressure developed by larger bored and stroked engines with higher compression turning high revs will force the unrelieved pressure out any weak area in your engine sealing. Valve cover gasket area being a common one. The front and rear crank seals being a bad one to have start leaking and even the case sealing area between the case halves and oil screen cover can fall victim. More vents are better! Get your drill out to add holes to your new valve covers or find a way to add additional vents to your engine above the crankcase oil level. That is only a suggestion, I am not an expert on this but have had a fair amount of firsthand experience.
I'm 50/50 on them... I've had motors that absolutely needed them and would force a leak somewhere without them, and I don't think they can hurt anything so no harm in running them unnecessarily.
That said, I do not agree with them being on the back side of the valve cover. It has been my experience that they are best placed on the front sides. I have noticed that the catch can/breather will get a lot more oil in it when they are placed on the back sides, and my educated guess is that more oil is forced into the breathers on acceleration, both from pressure and from the force of acceleration itself.
Regarding crankcase breathing: more is more.
@Jimmy V. Thank you, Sir. Indeed, I plan on revving past 4500! ;-) I'm still learning what I've got in this motor, and my mechanic tells me it's got a modified cam -- and it feels like it. I guess I'll be drilling the new cam covers.
@chines1 Carey, thanks for the information. I'll need to go the Googlenator to see if I can find some pics of these things being mounted on the fronts of the covers. My inexperience needs some inspiration on how to plumb that configuration. ;-)
@Stan Galat Stan, Thank you. Y'all have convinced me to keep 'em. Perhaps I can get some ideas on how to install them a bit more elegantly, at the very least switching out the blue garden hoses for some braided stainless. 
My Spyder originally just came with a hose going from the oil fill tube to the left carb top. This wasn't enough. I had some leaking from the crank seal behind the pulley.
I tried a few things then ended up venting the valve covers into a tin can that a wine bottle came in. The valve cover hoses attach at the ends, the oil tube fill hose attaches at the bottom and the carb hose comes out the side. The oil tube fill hose has two jobs, vent and to drain the oil that collects in the can. The carb hose has a perforated tube that is wrapped in stainless scrub pad inside of the tin can. I also soldered both lids on either side of the can to prevent leaking. The tin got mounted to the firewall.
You can kinda see most of this in this shot. This is the final version.
I chose to weld some AN fittings onto my existing valve covers. This process warped the covers ever so slightly and they weep at the weld. Oh well.
The tin can is mounted to the frame tube with large stainless hose clamps. This is a Vintage frame, so this might not apply to your car.
Here is a link to what I started with. https://www.speedsterowners.com/topic/breather-box
In the link there are also other ideas from other members. That's the beauty of our toy cars, you can do whatever you like.
@Carlos G Wow -- tons of great information in your post here, and then I went and read the other thread you shared. I learned a lot! Now that I've decided to keep the venting, I just need to decide how to do it -- leave it as is, or employ one of the ideas presented.
Beautiful engine bay, too, Carlos >> very well done. 
I would go with picking up the fumes from the oil filler tube which is the higher point and you wouldn't get much oil being sucked up. But I split the hose into both carb tops which doubles the vacuum at high revs. I never had any leaks from this set up.
@Fastal posted:
Talk to me about that shroud. I’m going to need a moment — I think I’m starting to swoon.
@Fastal Thank you. (and, btw, I looked at this car on your profile -- beautiful) So, for this newbie -- you've got a hose attached to the oil filler tube, and this hose then feeds to the top of each carb top -- is that it? Is there any additional plumbing involved?
Besides Carlos and Ed, I made my own breather. A long time ago, too.
I used a 2" exhaust pipe about 20 inches long, and installed it angled in a nod to the OG Spyder breather. The original Porsche one drained into the top of the 4-cam crankcase. I didn't put a large(1" or so) hole into the case like Porsche, but I did use a 3/8" steel fuel line angled back to the universal case oil-fill blockoff.
I vented both valve covers and the top of the case. Valve covers have AN8 lines. The case line is 3/4" I.D., using the distributor hole(I have EFI). There is stainless steel wool packed into the top 8 inches of the breather.
I'm running a dry sump system and have both the top of the breather and the dry sump running to a catch tank with a breather filter on top.
I used all nylon braided AN hose. I also had a welding professional Tig the bungs into my aluminum valve covers. I like the look.
The whole system works like a charm with 6500 rpm shifts, all day long.
I don't have anything to my carb tops, and I do have the vents on the back side of the valve covers. Your mileage may vary...
The shroud was a little bit of an optical illusion. I started with a center mount shroud and placed a larger shroud over it using a an old pro stock Holley carb top surround. The cone is from a radio controlled plane and the sticker "Competition Motors" from North Hollywood is a fictitious shop that doesn't exist but was the shop that worked on James Dean's car.
@DannyP >> wonderful setup. I'm digging the creativity in all of these! So, when you say you plumbed the "back side" of the valve covers, I'm assuming you mean the "facing rearward" side of the covers?
@Fastal Indeed, that shroud and fan look incredible! Regarding your breathing mechanism >> did you just run a hose from the oil filler to each carb? There was no other piping involved? Thanks!
Installing a set of Total Seal oil control rings on your pistons nearly eliminates doing anything but using the stock breather system. My engine compartment was bone dry after installing them.........Bruce
@Fastal posted:I would go with picking up the fumes from the oil filler tube which is the higher point and you wouldn't get much oil being sucked up. But I split the hose into both carb tops which doubles the vacuum at high revs. I never had any leaks from this set up.
Do you have any pictures of the front side of the fan housing ?
Did it start with the old style center mount stand that took a stock 12V bug generator or alternator ?
Did you use the Aluminum shroud that came with the center mount stand ?
Or just some more pictures
Thanks
@aircooled Bruce -- very interesting. Thanks!
As I mentioned in my initial post, I'm interested in exploring ways to enhance the breathing, but without drilling my new valve covers (although Danny's method of doing this looks mighty nice.)
John......I welded tubes into my steel valve covers because I didn't feel secure installing the ones with nuts and a gasket on them. If I had aluminum covers I would have welded those as well. A competent welder can make them look really nice. Of course you could tidy up those welds by rounding them out and blending them in to look like they were part of the mold for your covers.........Bruce
@aircooled Thank you, Sir. I've learned a bunch from y'all so far on this thread, and I'm now convinced to have my new valve covers vented. In fact, given my reading of prior threads on this subject here on this forum, I may be looking into a breather box.
@Wulfrik (John) posted:@DannyP >> wonderful setup. I'm digging the creativity in all of these! So, when you say you plumbed the "back side" of the valve covers, I'm assuming you mean the "facing rearward" side of the covers?
Yes, toward the rear of the car.
My engine came with Total Seal 2nd compression ring on the forged Mahle pistons. I did the same when I replaced them, using the stock Mahle top and oil rings.
@aircooled posted:John......I welded tubes into my steel valve covers because I didn't feel secure installing the ones with nuts and a gasket on them. If I had aluminum covers I would have welded those as well. A competent welder can make them look really nice. Of course you could tidy up those welds by rounding them out and blending them in to look like they were part of the mold for your covers.........Bruce
Yeah, you could. But why cover up and/or hide that beautiful work? The whole point of a professional weld job is NOT having to mess with it after. There is no possible way I could weld that nice.
@imperial posted:Do you have any pictures of the front side of the fan housing ?
Did it start with the old style center mount stand that took a stock 12V bug generator or alternator ?
Did you use the Aluminum shroud that came with the center mount stand ?
Or just some more pictures
Thanks
I have recently sold the car but here is a picture of the front when I was building the car.
Thanks for the picture , please post anymore of the motor if you have them....
Someone found a center mount grnerator stand at the swap meet today for $10
