I have to do a remove and replace on my intake manifold to fix an oil leak.

I know the last time i was attaching the tpi runner at the back i damaged
the threads in the last hole on the drivers side. This is the last bolt hole
at the bottom of the runner, where the runner joins the intake manifold.

Would any third gen wizard off the top of their head know what metric size
that bolt is? Is it M-10 (10mm in diameter) or M-12 or M-8?

It is a torx bolt so there are no markings on the head of the bolt.

I need to tap that hole and i want to buy the correct size tap before i
dis-assemble.

Is it coarse or fine thread?

That part of the motor is 1988 305cu in vintage.

Thanks

1988 IROC Z28 355 cu. in., 4 bolt main, Melling Oil Pump, Clevite bearings, Speedpro pistons, C&A rings, ARP rod bolts, Manley pushrods, Ported & Polished Heads, Custom Chip and Cooling, 180 Thermo, TPI, 52mm TB, K&N, AFPR, Gutted Airbox, Airfoil, MSD 6AL and coil, A4, B&M Shifter, 2500 stall, Transgo Stage 2, Shift Kit, Corvette Servo, Trans Cooler, 3:73 gears, Auburn, poly, LCA's, MAC exhaust, 245/45/ZR16....

 

Why don't you just take the bolt with you when you buy the tap?

------------------
82 z28 350cid, vortec heads, comp 262h cam, Holley 600cfm carb, 2in twice pipes, MSD ignition, turbo 350 trans, 3.73 posi, manly b&m megashifter

 

3/8-16 i believe
you can find the diameter by checking it with an open end wrench, just slip the wrench over the bolt.

------------------
ICON Motorsports

1st & 3rd

 

They are metric, 8mm. I think the pitch is .75
Taking a bolt with you is a good idea. Its easy to verify the threads that way.

 

Thanks guys for your feedback.