Pretty irritated right now

[ctrout71]

I picked up a set of GT40 heads "from a 93 Cobra" a while back and finally decided to install them so I ordered my ARP bolts. Since this head supposedly came from a Cobra, I didn't bother to verify the bolt hole size. When the bolts got here, I started setting everything up to do the swap and I found out that the bolt holes measure exactly 1/2" across so now I've wasted $50 on bolts I can't use! I went with the 154-3701 ARP bolts. Which ones should I have gotten, or is there a set of adapter bushings or something I can buy? Oh, and what would you all suggest I do about being lied to about the heads?

 

[Vinnietbird]

They may be Lightning heads, or drilled out for a 351W. There are bushings made to adapt the 351W heads to the 5.0. No big deal.The seller may have thought they were Cobra heads. Who knows. The same way so many people call Explorer intakes "Cobra" and GT-40" intakes. Either way, buy the bushings and you'll be fine.

 

[stykthyn]

Fwiw the 95 cobra r had gt40 head drilled with 1/2 holes.
Get these Trick Flow Specialties TFS-51400419 - Trick Flow® Head Bolt Bushings - Overview - SummitRacing.com

 

[wythors]

Well, never mind.

 

[ctrout71]

Thanks a bunch for the link stykthyn. Jegs wanted twice that amount for the ARP bushings.

 

[Rick 91GT]

Our 93 Cobra also had 1/2" holes from the factory, no bushings installed with the 7/16" bolts. We also added the bushings down the road when the head started lifting under boost.

 

[ctrout71]

Thanks for the info Rick. I guess it wasn't the seller's fault then. So did the 93 Cobra have a 5.0 or the 5.8 then?

 

[larrym1961]

'93 Mustang Cobras had 5.0's in them.

 

[f8tlfiveo]

I'm pretty sure they should be 7/16 (.4375) for a 302.

 

[Rick 91GT]

I'm pretty sure they should be 7/16 (.4375) for a 302.

Normally yes, however every 93 Cobra I have had the pleasure of working on has 1/2" holes in the GT40's, 7/16" bolts....not sure why.

 

[93STVCobra]

Soon you'll have the pleasure of working on mine Rick=P if I don't shot myself by then.

 

[f8tlfiveo]

Did they use a sleeve in the 1/2 hole for the smaller bolts on the cobra?

 

[Rick 91GT]

Did they use a sleeve in the 1/2 hole for the smaller bolts on the cobra?

Not from the factory....and to be honest it usually isnt a problem till you add some extra cylinder pressure then the head tends to move easier. The ARP bushings/sleeves can be added to resolve those issues....

 

[Mustang5L5]

If they are cobra heads, they will have the thermactor ports in them and functional. The later Explorer GT-40's don't have these