Lustalbert Posted April 17, 2006 Report Share Posted April 17, 2006 Anyone know of a shop that would be comfy moding a GM TBI unit? I have a TBI unit from a 5.7 ch*bby, 42MM bores. I want to get it bored to 50-54MM. The stock rating of 400 CFM just isnt cutting it on a 455. Would also need the throttle plates made and installed. Anyone feel comfy in thier boring/machining skills? BTW a modded one on ebay goes for about 200, looking to get in cheaper than this. Quote Link to comment Share on other sites More sharing options...
Guest 614Streets Posted April 18, 2006 Report Share Posted April 18, 2006 Yah u need more tbi I have a 670 cfm unit on my 2.8! Im suprised you cant find a holley unit cheap on ebay or a 454 unit from a local yard. How many psi are you running on your current tbi? Quote Link to comment Share on other sites More sharing options...
Guest 614Streets Posted April 18, 2006 Report Share Posted April 18, 2006 In fact heres a 670 unit on ebay at 150 with 9 hrs left . http://cgi.ebay.com/ebaymotors/Holley-670-CFM-TBI-Unit-BOLT-ON-87-89-Chevy-GMC_W0QQitemZ8055685441QQcategoryZ33558QQssPageNameZWDVWQQrdZ1QQcmdZViewItem That one has the newer delphi injectors to which means its one of the good holley units , the older units have black caps over the injectors and suck for 2 reasons , 1 the injectors fail and 2 the injector hold downs are plastic. Im wondering why you wouldnt run a 4 barrell tbi. Quote Link to comment Share on other sites More sharing options...
Lustalbert Posted April 18, 2006 Author Report Share Posted April 18, 2006 Trying to do it on the cheap. This is going to be something that runs, but isnt really permenant. I am curently running about 12 psi, but i have a regulator and am planning to bump to about 30. I have the orange injectors, I belive they are 45lb. Quote Link to comment Share on other sites More sharing options...
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