I'm assembling a 91 tuned port injection (off of a Z28) for an older vehicle. I have "almost" a complete bolt set with one bolt missing. It is the hold down bolt for the fuel lines at the front of the intake where a triangular piece of metal holds both the in and out fuel lines to the bottom of the intake. I have tried every size bolt that I can get my hands on with no luck. Threads appear to be metric but an 8mm bolt is a loose fit in the hole although the threads appear correct. I have even tried an assortment of SAE threaded bolts with no luck. Does anyone know what the bolt size is for this hole. I appreciate any help you guys can give me.
Ken

 

On my '87 and '90 TPI intakes they are same size /thread bolt as holds runners to plenum

 

AFAIK all the bolts that go into the intake manifold itself are metric. So... if its an 8MM bolt its just a different thread pitch than what you have. There are at least two and maybe three thread pitches for that size bolt. I'll see if I can find out which, I have an intake handy.

Well I cant find a 10mm bolt, but thats what it has to be. A 3/8" coarse almost threads into it so... 10mm should be correct. Its not 8mm, that slides right in with no real thread contact. So it should be a 10mmx1.5

 

Finally found a parts drawing and list on the forum (didn't copy URL) but it is a 3/8" - 18 X 3/4" bolt. I ended up buying a socket head cap screw and cutting it down to about 1/2" in length to make it fit between the fuel lines and the plate. Thanks for everyones help.

 

Looked back in my history and found the URL.
https://www.thirdgen.org/forums/tpi/...tance-tpi.html

There are three post with image files that show drawing and associated parts. I looked through the local dealers books yesterday but none show the detail that is in these drawings.
Thanks again,
Ken