Heli coli help

[bonnie&clyde]

So im putting my oil pan back on my 351 and one of the bolts was messed up, so I went to autozone and bought some heli coils and a tap, the thread on the oil pan bolts is 5/16 so I bought some 5/16 heli coils, the package says use a 21/64 drill bit to drill out the hole which I did, but I cant find anywhere that tells me what size tap to use, anyone on here know??? Trying to get this done tonight

[Mach1]

Special size tap usually

[4.0x3.48]

21/64 drill, and then a 5/16x24 STI tap. They sell a kit that has the inserts, bit, tap, and insertion tool.

[bonnie&clyde]

Crap, I knew I should have bought the kit that had the tap in it but I was trying to save some cash

[bonnie&clyde]

21/64 drill, and then a 5/16x24 STI tap. They sell a kit that has the inserts, bit, tap, and insertion tool.

I saw the kit but it was like $50 I think, so I jusy picked up a tap set that has like 6 diffrent sizes for like $12 and 5/16 heli coils for $9, guess I'll have to go get the kit instead

[4.0x3.48]

Yea, they're not cheap, but it'll be fixed forever. Helical inserts are good stuff.

[Torinoman]

Tap and die sets are like 30 bucks at harbor freight. I'm not positive they have a set that has the needed tap but it's worth a look. Find a 20% off coupon and you'll save some coin and you'll have some other taps of needed.

[4EyedTurd]

Keenserts>Helicoil

[AnthonyS]

The helicoil taps are not standard sizes if I recall correctly. You need a set of helicoil taps or the kit.