As J. Matsko said, if you have a set of heads that will flow, but can't you also jet the 48 IDAs to run on a smaller motor, even if you don't have the head work to support them.
Just curious, I'm not going to run 48 IDAs on a 1641.
Yep, it works, and can work damn well. Displacement isn't an issue, its all about the total package. A buddy of mine here in Marysville (Spencer Medford) had a 1641 w/IDA's back in the day, and it ripped. He upgraded with better heads, went to 92mm p/c's and even threw an FK-87 at it and it was the fastest VW in town for quite a spell. Nevermind there were only 4 VW's in town, and 3 of em were stock.
Those same IDA's are now on my brother's 2275 (which will probably never run), I bought em from Spencer about 6 years ago for $400. Nice.
This custom built machine built in the very early 70s by Troutman and Barnes, for a weathly VW Porsche dealer ran a 1600 AUTOSTICK w/ 48 idas...The car was famous for being seen in the day whisking such luminaries as John Wayne and P L Newman to Oscar night and such.. made quite a stir back then .. about 10 years ago Ray Schubert, then owner of Volks Authority in San Jose used it for his wedding .. Ray popped the carb tops when it was at his shop and found custom made 26 vents..............................
Lanky, i have had the book since the mid eighties.. the store I bought it at has long since been razed.. I did see it was available on amazon and saw asamba ad recently, so it's out there .. Some great pics.. i'm sure you will enjoy it. d
TodayCase: original AS41
Pistons:JE 86mm 24mm comp hight
Cylinders:Stock 85,5mm honed to 86mm
Heads:043 40x35mm valves
Rockers:Jpm two stud 1,5:1 ratio
P-rods:Manton 3/8" cromoly
Flywheel:180mm stock lightend
Clutch disc:cush lock
Header:Custom made 1 5/8" tuned length
Manifolds:Custom made tuned length(second order)
"Changed the main venturies from 37 to 39mm.
The engine responded really good with an improvement from 138,8-143,3kW or 188,7-194,9hp the torque increased from 191-195Nm (138-141lbs).
The attiude of this engine is really something, nice and smoth at idle and kicks really hard if you want it to".
"There would probably be some more improvements with bigger venturies but as it is now there is no bog or hassitation between low and high circuit and as this engine is to be used on the street I prefere to have it like this.When using too big venturies you often notice a hassitation between low and high circuit even sometimes with the third progression hole modification."