Trying to find LS1 75mm Throttle Body
 

Looking to replace the 3 bolt 75mm throttle body on my LQ9 with LS1 intake. Can't seem to find one with the connections like the one i have. There is a hose from the water pump that goes through a tube on the bottom of the TB and then to radiator. Do i have to have that or can i bypass it? I have a 75mm port in the manifold so i assume i have to match that. Any suggestions for a vendor to find this?


Thanks,
Keith R

I thought the LS1 had a 78mm TB? Either way, the coolant tubes are just to warm the TB for emissions if I am not mistaken. I believe you can bypass it without issue.

SS.slp.ls1 I measured the throat and it was 75mm. This motor came out of a Silverado 2500HD but the intake manifold i was told is an LS1 not sure which year or model..Could i go with a 78mm?

Keith R

Any 3 bolt will work, and usually considered 78mm. The vacuum port on top is turned different for cars and trucks but I just heat the throttle body at the base of the port and turn them to where I need them.

that looks like a everyday run of the mill LS1 TB.....hell i have 2 sitting around gathering dust

They are 75mm. OP, yes bypass that lower hose, you dont need coolant running through there. Just about any 3 bolt tb will work, as stated above.

Ok..Thank you for the replies!!! Going to clean this one up and polish it and see how it goes. Having some stalling and surging idle after the car is driven for about 15 minutes....Before that it runs and idles fine. Checked for codes and nothing is coming up. Didn't find any vacuum leaks and MAF and MAP are only a few months old.


keith R

There was a minor butterfly difference. I think 01 and 02 fbodies got a longer more progressive butterfly cam (thing the cable pulls on). Its noticeably bigger/longer then earlier years and trucks. That looks like a truck TB. Picture truck ones like yours as that piece looking like a half a pizza, and the odd fbody ones looking more like a crescent moon.