I have two missing bolts I need to replace: 1) the bolt that holds the fuel line bracket to the front of the driver's side head on my 5.7L TPI is missing. 2) One of the bolts that retains the throttle position sensor has sheared off flush with the throttle body(previous owner, not me!).

Anyone know what size bolts they are and where to get them?

 

Any chance you could take a pic of the bolt sites on the engine and post....?

 

For the throttle body - pull the other one and measure it. Calipers and a thread gauge.

For the other - find something that threads in an measure that. It's likely SAE If it's going into the head. So probably 5/16 or 3/8. Likely a coarse thread. So either 5/16 x 18 or 3/8 x 16.... would be my wild a$$ guess.

GD

 

For the tps it’s a odd metric size 4.5mm iirc. You can ask in the wanted classifieds section. Or retread to a fine thread machine screw.
i think it’s 11/64

 

Get the TPS screw from the junkyard. Look for any same generation GM, TBI, TPI, EFI V6, etc should all be about the same. Worst case, drill and tap the next size larger for a standard machine screw.

The fuel line clamp bolts to the exhaust manifold stud until 88, when it started bolting to the serpentine bracket. m8x1.25x16 is the serpentine bracket bolt.

 

Bolts are cheap. Go to your local hardware store and pick up a couple bucks worth. Ace, True Value, etc. They sell grade 8's too. Dont waste your time and money at the dealership or junkyard.