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Tue Apr 04, 2017 1:25 pm

I will be rebuilding my top end soon and i will be going to a 1641 and i was wondering which set up i should use. ive read positive and negative things about having a single carb (progressive or single 40 idf) as well as having duals like weber 34s. my engine is stock with a vacuum advance distributor right now. could i install either of these now or should i leave it stock until rebuild? this is my first air cooled and i really dont know what to use. thanks for the help!

Tue Apr 04, 2017 2:13 pm

Have the heads bored to 90.5-92 while you are having the valve job done. They more then likely need the sealing surfaces cleaned up anyways. Then you can run thick wall 88mm's instead of the thin 87's that will warp within 3000 miles. Have the machine shop flycut them a little deeper so you can bump the compression to about 8.25-8.5. Get a real nice 3 angle valve job done.

Then add dual single barrels and a 1 3/8" header w/hide out muffler. A center mount is not worth all the extra headaches when you are already considering duals. ICT's are fine and easy, but they will be about maxed on your 1600. Dual 40mm Kadrons would be better, but the manifolds are getting a little out of hand on the price. The Empi Ict's arent that bad for the price, and a good place to start learning about dual carbs. You will need to replace the aluminum hex rod with a steel one if you ever want to get it to sync correctly.

Brian

Tue Apr 04, 2017 2:18 pm

x 2

Excellent advice!

Tue Apr 04, 2017 8:10 pm

Being this is your first Air Cooled
You'll need to know about a few things to make this excellent advise work.
Once you get your thick wall 88's,
https://vwparts.aircooled.net/Piston-Cylinder-Set-88mm-x-69mm-Slip-In-p/vw8800t1k.htm?CartID=1
you will need to clean and assemble them on your case.
Then you can measure your deck height,

You want your deck height to be between .040" and .070"
If its less than .040, than you can order spacers.
https://vwparts.aircooled.net/1600cc-Barrel-Shims-1300-1600cc-Set-of-4-p/1600cc-barrel-shims.htm
with that measurement you can plug your desired compression ratio,
and your measured deck height to determine your Required chamber volume.
http://cbperformance.com/v/enginecalc.html
With that you can have a machine shop to machine your heads to give you your requested chamber volume.
Or order new:
https://vwparts.aircooled.net/Chinese-Fuel-Injection-Dual-Port-Cylinder-Head-p/043-101-355ck.htm
You'll pay an additional $75 to bore them for the 88's, and specified cc will cost another $40.

Thu Apr 06, 2017 10:27 am

jhbugmania wrote: . . . could i install either of these now or should i leave it stock until rebuild?

There's an old saying about new carburetors and new engines: "An unknown carburetor on a known engine, or a known carburetor on an unknown engine, but never an unknown carburetor on an unknown engine."

I would definitely shake down your new carburetors (go with the duals, man!) on your current engine before slapping them on a freshly rebuilt one, especially since a 1641 isn't really all that different performance-wise from stock, all else being equal, so they shouldn't require a whole lot of readjustment when the time comes to swap them over.

Good luck with whatever you decide to do.