I'm in the process of mocking up my re-built SBC to find unanticipated problems and have been very successful: I've run into a big problem.
I'm using a Weiand 142 blower "kit" P/N 6500-1 and Weiand's recommended Holley carb, P/N 80572 (it's a boost-referenced Holley 4150).
The problem is that I'm also using a 700R-4 transmission and the Holley carb, according to the instruction manual, " ... is NOT designed for use with ANY automatic overdrive transmissions." (Of course, they only disclose this in the installation instructions; it's mentioned nowhere else.) This is my big problem.
Obviously, what they are referring to is the lack of any appropriate bracketry associated with the throttle cable attachment point so that a TV cable can be attached. This means that Holley's "solution" (P/N 20-121, their 700R-4 kickdown throttle bracket) has NOTHING to mount to. Even if it did (I have one), the geometry is all wrong, only pulling the TV cable through a 30 degree arc instead of the required 78 degrees. That may be why others have had a problem with their 700R-4s even when using the Holley bracket.
Working from info at Sumner Patterson's site, I found I could modify/construct a bracket to add the 700R-4 functionality that Holley left out.
Basically, I constructed a piece of cardstock with the correct geometry like he did, located the correct placement of the TV cable stud, and mocked up a solution. I will simply cut up the otherwise-useless Holley 20-121 bracket and weld it to the carb in the proper place. Based on my mock-up, the TV cable stud will move through the correct geometry from closed to WOT. In theory, I've solved my problem (but I haven't done it yet so no pictures).
I'm posting this because
1) I haven't been able to find anything where somebody else already solved this problem;
2) There may be a better way to do this I didn't find (remember that the Holley adapter and similar adapters will not work with my particular "older" carb and the Holley adapter may not really work at all); and
3) I'd like to get some feedback and maybe a little validation of my thinking before I actually weld stuff to a brand-new carb (which I purchased 4 years ago, so there's no taking it back).
As a helpful reference, these links provide useful information:
Sumner Patterson's site: http://www.purplesagetradingpost.com/sumner/techinfo/700R4p1.html
TV System 101 http://www.tvmadeez.com/article/index.php
700R-4 FAQ http://700r4.com/faq/faq.shtml
Speedo Gear Calculator at http://www.bowtieoverdrives.com/index.shtml
Useless Holley bracket: http://www.holley.com/20-121.asp
Pics of identical carb/blower: http://www.camaros.net/forums/showthread.php?t=152602
I'm using a Weiand 142 blower "kit" P/N 6500-1 and Weiand's recommended Holley carb, P/N 80572 (it's a boost-referenced Holley 4150).
The problem is that I'm also using a 700R-4 transmission and the Holley carb, according to the instruction manual, " ... is NOT designed for use with ANY automatic overdrive transmissions." (Of course, they only disclose this in the installation instructions; it's mentioned nowhere else.) This is my big problem.
Obviously, what they are referring to is the lack of any appropriate bracketry associated with the throttle cable attachment point so that a TV cable can be attached. This means that Holley's "solution" (P/N 20-121, their 700R-4 kickdown throttle bracket) has NOTHING to mount to. Even if it did (I have one), the geometry is all wrong, only pulling the TV cable through a 30 degree arc instead of the required 78 degrees. That may be why others have had a problem with their 700R-4s even when using the Holley bracket.
Working from info at Sumner Patterson's site, I found I could modify/construct a bracket to add the 700R-4 functionality that Holley left out.
Basically, I constructed a piece of cardstock with the correct geometry like he did, located the correct placement of the TV cable stud, and mocked up a solution. I will simply cut up the otherwise-useless Holley 20-121 bracket and weld it to the carb in the proper place. Based on my mock-up, the TV cable stud will move through the correct geometry from closed to WOT. In theory, I've solved my problem (but I haven't done it yet so no pictures).
I'm posting this because
1) I haven't been able to find anything where somebody else already solved this problem;
2) There may be a better way to do this I didn't find (remember that the Holley adapter and similar adapters will not work with my particular "older" carb and the Holley adapter may not really work at all); and
3) I'd like to get some feedback and maybe a little validation of my thinking before I actually weld stuff to a brand-new carb (which I purchased 4 years ago, so there's no taking it back).
As a helpful reference, these links provide useful information:
Sumner Patterson's site: http://www.purplesagetradingpost.com/sumner/techinfo/700R4p1.html
TV System 101 http://www.tvmadeez.com/article/index.php
700R-4 FAQ http://700r4.com/faq/faq.shtml
Speedo Gear Calculator at http://www.bowtieoverdrives.com/index.shtml
Useless Holley bracket: http://www.holley.com/20-121.asp
Pics of identical carb/blower: http://www.camaros.net/forums/showthread.php?t=152602
