Brent94Z

The AS&M 58mm tb does NOT have its holes drilled on center in relation to the stock throttle body. The Holley 58mm tb does but the AS&M does NOT. If you bore your intake to 58mm and use the stock holes as a reference, they will not be aligned correctly for the AS&M tb.

Here is a gasket scan of a 58mm AS&M tb gasket for ya...
http://www.bfranker.badz28.com/misc/58mmgasket.JPG

sweetride45

I see what you mean. Looks like there is more meat on the left than right...that's kewl. I ordered it, and will wait for the gasket to do the intake work Thanks!!

Brent94Z: Are you familiar w/ IAC passages causing split BLM's w/ it?

Brent94Z

I have not had issues with this myself. Not sure of any others problems though?

Also not sure what you mean by more meat on the left than right... the center of the AS&M holes are equal distances on both sides from the center of the stocker holes

sweetride45

I meant that it looks like there is more gasket on the left than the right...by that picture...

Pasky

I've seen lots of idle issues with 52 and 58 throttle bodies and all the solutions used some sort of spacing fix or cleaning of the throttle blades/spring as they seem to get stuck.

Injuneer

Not sure why you feel it was ignored... it got a couple responses. And the original "topic" was "offset". I'll merge the threads and alter the topic.

sweetride45

A spacing fix? Can't be the cleaning part, since it'll be brand new

Dave88LX

Mine doesn't look offset there Brent.

arnie

Yes the bore spread is definately different, or 'off center' in relation to the oem holes. This pic, courtesy of Dave plainly/clearly shows it: http://paradox.shacknet.nu/dave88lx/...8mm-gasket.jpg

BTW, I personally do not recognize the 58 mm AS&M TB as such. That TB is definately NOT a 58 mm bore TB, and I prefer to call it was it really is...... a 57 mm TB. Those that own one, measure the bores sometime. Also, if any IAC or split BLMs are experienced, it is understandable. That TB was not designed for the LTx series engine.

sweetride45

I have the TB now, and it looks like a NICE piece...so, how do you solve the split BLM's then? Has everyone come across this problem?

arnie

There is a need to isolate the IAC circuit in the TB.

sweetride45

What do you mean, "Isolate the IAC circuit"?

Brent94Z

Whatcha mean, Dave? I looked at the picture in the next post after yours and it looks like your picture and the holes are definitely not on center in relation to the stockers. Not sure what you mean?

arnie

I've seen 3 or 4 different sites in the past with pics, explaining the procedure used to modfify the IAC circuit to eliminate (or at least improve) the split BLM syndrone. The modification amounts to isolating the circuit to something that more or less approximates what the oem TB has. Looks like I've got one for ya: http://www.hashmarks.com/techtips/throttle_body_mod.htm

Check out this site for Jeff's mod as well: http://para.noid.org/~lj/ Had a 'Jim Evans' site that used this site for reference, but link is no longer active. Maybe, someone else will come forward with a link to a site.

sweetride45

Has everyone w/ a 52+mm TB (preferably AS&M) discovered that they have to do this "Copper Tubing" mod for it to idle correctly? I don't like the idea of drilling and hacking into this $500 piece.