I am thinking fill it with JB weld and you can make a smooth surface on the inside and outside. A bit tricky though because you definetly do NOT want any of that JB weld to break loose and enter the engine....and this is basically permenent....i you can always go back if you just put the stock part back in without the butterflies, or use some type of bolt/nut menthod.

OOpss, I fogot to add 'blocking plate' to my poll...like these:
http://www.k2rd.com/Online_Catalog/BlockOffPlates.htm

 

I dont think it really matter since you wont see it anyway, so looks arent really an issue. A bolt would work BUT what ever doesnt make shavings to go in the intake or can possibly be sucked in with wear

 

Definitely the K2RD plate, looks clean, is inexpensive, and works perfect.

Matt

 

the double throttle hole is only the diameter of a pin.

 

tap the hole with 1/8 npt pipe or similar threads (use a tapered thread) and then plug with a suitable plug (internal allen head perhaps?) with some sealant.

If you do this right, it can never possibly fall inside the engine due to the taper on the threads, and it will be flush mounted with no bolt heads sticking out to scrape your hands when you try to fit them back there. I like doing this plug method over a block off plate because it saves the 1/4 inch or so of clearance back there... which sounds like a small savings until you are trying to fit a tool back there and it just barely won't fit

Brian

 

actually spirit, once you remove the actualtor aparatus and the bar that holds the double throttle butterflies, it is a fairly large hole.

 

this is what I was thinking, do you use K2RD's place Matt?

...and if so were you concerned about the proximity of the edge of the place and the edge of the outer hole (not much contact area for a good seal?)...did you use somthing under the plate to help seal it?

 

ahh yes, nice method, very clean/safe result.... I may try this style.

 

i made a small plate from 1/8 aluminum that is bolted on with the 2 stock bolts and sealed with silicone.

 

ill sell you the block off plate if you'de like i have a spare

the harder part is removing the junk

ive done it twice used a block off plate both times

maybe a bolt would be better though so air can flow smoother inside the uim?? if you look at it youll see what I mean

 

Just tap the hole and use a headed bolt, that way it can't get sucked in if dislodged some how. That's how Cam at Pettit has done it for about 8 years.
art

 

I used the 1/8th npt trick with some silicone sealant on top of the allen head just in case.