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SVT Shelby GT500
GT500 lower intake on GT Supercar heads?
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<blockquote data-quote="Harley#356" data-source="post: 15972400" data-attributes="member: 62603"><p>Searching for other stuff, and stumbled across my old posts so I figure I'd update folks on what I ended up doing, incase any folks in the future are also looking to do the GT500/CJ lower intake on GT supercar heads.</p><p></p><p>I've heard slot the manifold, but there's no way to slot it far enough without breaking thru the sides on the front portions, plus you'd have to machine out a flat seat again since it's in the sloped coolant port towers. It actually wasn't bad at all to re-drill new holes in the heads, adjacent to the factory GT supercar holes. PATIENCE & PRECISION are key. The holes are literally the thickness of the threads apart.</p><p></p><p></p><p>First I bolted the intake down with all the bolts that lined up (just the 2 fwd & 2 aft ones don't). Then I got a drill bit the exact size of the manifold thru holes so I knew it was perfectly centered, and I lightly drilled a dimple in the head for dead center</p><p></p><p>[ATTACH=full]1505938[/ATTACH]</p><p></p><p></p><p>Then starting with a very small drill bit, I drilled a pilot hole straight thru, then slowly stepped up drill bit sizes till I got to the exact drill bit size for an M6x1.0 tap. IIRC it calls for a 5mm drill bit. I bought a set of metric bits specifically for this. You could find a close enough SAE bit, but with tiny screws like these, close enough isn't good enough, I wanted exact per spec for the tap. You don't need crazy expensive metric bits, a $15 set on amazon is perfectly fine for drilling aluminum. IIRC I started with 1/8" SAE, stepped up a couple sizes, then swapped to metric bits and went 3.5, 4, 4.5, 5. You can step up sizes faster, but like I said, patience & precision are key here...</p><p></p><p>In this pic, I did thread an M6x1.0 bolt from the bottom up to fill the factoryy hole, but it's not necessary. The others I did not do that.</p><p></p><p>[ATTACH=full]1505939[/ATTACH]</p><p></p><p></p><p>Tapped the hole with M6x1.0 tap, little WD-40, then cleaned with carb cleaner. Slight chamfer on the top with a deburring tool to slightly chamfer the edge like the OEM hole for easier bolt alignment.</p><p></p><p>[ATTACH=full]1505940[/ATTACH]</p><p></p><p></p><p>Repeat that anxiety-inducing process 3 more times, praying you don't screw one up lol. Luckily enough I knocked out all 4 perfectly. (I also popped those rear freeze plugs out later for my coolant crossover).</p><p></p><p>[ATTACH=full]1505941[/ATTACH]</p><p></p><p></p><p>Sit back & admire the Ford engineers that decided to shift the 4 outer bolt holes by 1 bolt diameter, just so people had to work a wee bit harder to interchange parts lol Separate the men from the boys haha</p><p></p><p>[ATTACH=full]1505942[/ATTACH]</p><p></p><p></p><p>Bam.....dual bolt patterns! If I ever wanted to change things up down the road, I've got the flexibility now of either style lower intake, and if I ever parted/sold this combo down the road, it'll work for either crowd. Not that I plan on doing either, but it's a nice solution.</p><p></p><p>[ATTACH=full]1505943[/ATTACH]</p><p></p><p></p><p>Everything bolted back together. And before people start getting concerned how close the 2 holes are to one another, sit back and think about it for a minute. There's something like 15 bolts holding the lower intake down, and they're only torqued to like 89 in-lb or something very light along those lines. There's also zero shear/torsion forces on these bolts, no side loading, no twisting, they're simply applying a downwards pressure. There's no concerns it would ever break thru the other adjacent hole, and honestly you could run entirely without them. Aftermarket coolant port fittings only use 1 of the 2 bolt holes. It's more of a peace of mind/OCD of using every manifold bolt for the most ideal/even clamping force.</p><p></p><p>[ATTACH=full]1505944[/ATTACH]</p><p></p><p>[ATTACH=full]1505945[/ATTACH]</p><p></p><p></p><p>All mocked together.....which is already all back apart lol. Mocked up to figure out what other ARP hardware & AN fittings I needed, now back apart till the replacement permanent goodies arrive.</p><p>[ATTACH=full]1505946[/ATTACH]</p></blockquote><p></p>
[QUOTE="Harley#356, post: 15972400, member: 62603"] Searching for other stuff, and stumbled across my old posts so I figure I'd update folks on what I ended up doing, incase any folks in the future are also looking to do the GT500/CJ lower intake on GT supercar heads. I've heard slot the manifold, but there's no way to slot it far enough without breaking thru the sides on the front portions, plus you'd have to machine out a flat seat again since it's in the sloped coolant port towers. It actually wasn't bad at all to re-drill new holes in the heads, adjacent to the factory GT supercar holes. PATIENCE & PRECISION are key. The holes are literally the thickness of the threads apart. First I bolted the intake down with all the bolts that lined up (just the 2 fwd & 2 aft ones don't). Then I got a drill bit the exact size of the manifold thru holes so I knew it was perfectly centered, and I lightly drilled a dimple in the head for dead center [ATTACH=full]1505938[/ATTACH] Then starting with a very small drill bit, I drilled a pilot hole straight thru, then slowly stepped up drill bit sizes till I got to the exact drill bit size for an M6x1.0 tap. IIRC it calls for a 5mm drill bit. I bought a set of metric bits specifically for this. You could find a close enough SAE bit, but with tiny screws like these, close enough isn't good enough, I wanted exact per spec for the tap. You don't need crazy expensive metric bits, a $15 set on amazon is perfectly fine for drilling aluminum. IIRC I started with 1/8" SAE, stepped up a couple sizes, then swapped to metric bits and went 3.5, 4, 4.5, 5. You can step up sizes faster, but like I said, patience & precision are key here... In this pic, I did thread an M6x1.0 bolt from the bottom up to fill the factoryy hole, but it's not necessary. The others I did not do that. [ATTACH=full]1505939[/ATTACH] Tapped the hole with M6x1.0 tap, little WD-40, then cleaned with carb cleaner. Slight chamfer on the top with a deburring tool to slightly chamfer the edge like the OEM hole for easier bolt alignment. [ATTACH=full]1505940[/ATTACH] Repeat that anxiety-inducing process 3 more times, praying you don't screw one up lol. Luckily enough I knocked out all 4 perfectly. (I also popped those rear freeze plugs out later for my coolant crossover). [ATTACH=full]1505941[/ATTACH] Sit back & admire the Ford engineers that decided to shift the 4 outer bolt holes by 1 bolt diameter, just so people had to work a wee bit harder to interchange parts lol Separate the men from the boys haha [ATTACH=full]1505942[/ATTACH] Bam.....dual bolt patterns! If I ever wanted to change things up down the road, I've got the flexibility now of either style lower intake, and if I ever parted/sold this combo down the road, it'll work for either crowd. Not that I plan on doing either, but it's a nice solution. [ATTACH=full]1505943[/ATTACH] Everything bolted back together. And before people start getting concerned how close the 2 holes are to one another, sit back and think about it for a minute. There's something like 15 bolts holding the lower intake down, and they're only torqued to like 89 in-lb or something very light along those lines. There's also zero shear/torsion forces on these bolts, no side loading, no twisting, they're simply applying a downwards pressure. There's no concerns it would ever break thru the other adjacent hole, and honestly you could run entirely without them. Aftermarket coolant port fittings only use 1 of the 2 bolt holes. It's more of a peace of mind/OCD of using every manifold bolt for the most ideal/even clamping force. [ATTACH=full]1505944[/ATTACH] [ATTACH=full]1505945[/ATTACH] All mocked together.....which is already all back apart lol. Mocked up to figure out what other ARP hardware & AN fittings I needed, now back apart till the replacement permanent goodies arrive. [ATTACH=full]1505946[/ATTACH] [/QUOTE]
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GT500 lower intake on GT Supercar heads?
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