I'm sorry David, I should have gave you more information.. I'll enlighten you. first off, when I first took an intrest in building a VW, I purchased alot of things before I learned what I know now. I bought 4 bugs about 2 weeks before BP-7. as soon as I got them home, I came to BP-7 and like a kid in a candy store, I just couldnt resist all the "cool things" that I found. so I Splurged!! hey, it was fun.. any way, here's the deal, one of the bugs I got (66) had a recently fresh engine in it. the fella said it was a big bore, but thats all i knew. while at BP-7 I bought a progressive weber kit, a merged header, a nice ceramic phat-boy muffler, among other stuff. since then I've been learning alot of information that I wish I knew earlier. now, I have my 64 pan and chassis completely restored and ready for the next step. so, I take the "big bore" out of the 66 and tear it down to see what I've got, with plans of fixing it for my project. heres the stinkin part. I've got a low mile engine that still looks great inside but its a dern 1641. with slip ins. so, in order to carry on my project (by the way, now Im low on funds), I decided to go ahead with the 1641 and just make the best of it. so I bought an engle 110 cam and mahle lifters, and started doing some port work on the heads. In fear of making them worse, I only done some mild "short side radius" work, so I didnt go overboard. I did leave the stock valves alone, other than a fresh lapping. anyway, I am just using this engine to get my car completed and then after I have a nice car, I'll build a nice engine for it. so a 1641, 110 cam, weber 2 brrl, headers, 009, and mildly ported heads are what I have. I just need to use the stuff I alreay have and get the car done. just so you'll know.. I have been building my own (air cooled ) race engines for the last 10 years, so I do understand most of what I read, I'm just new to VWs. making a set of flanges for some headers is no problem, I just wasnt sure how much air needs to come through the tube for manifold heat.