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I'm new to the whole off road biz but ol hat at engines. I purchased a CJ7 with a 258 3 speed combo in January. It's rough but a great platform to build around. On its first off-road adventure I noticed white gunk around the leaking dipstick and under the balance cover. Suspecting a blown head gasket I removed the head and took it to the machine shop to find it was cracked. Insert 4.0 HO mod. Order a top end kit, 4.0 Head bolts and header and away we go. Well today I got it all together and went to start the engine and it was extremely difficult to start and when it did start the RPMs quickly accelerated to alarming levels prompting me to shut the engine off. My two thoughts are "stuck" carb with fuel just flowing freely through or possibly the intake is misaligned and sucking air? The alignment of the intake is even with the top edge of the head and the dowel holes have been ground. Anyone's input on a possible solution or diagnostic check will be appreciated!
 

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I've not done this, but the alignment is the Key thing so you do not suck air.
 

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I have the offenhauser carb intake on my 4.6. The head is the 7120.
My jeep has always wanted to idle a little high. I suspected an intake leak. I sprayed starter fluid all around the ports and never noticed a change in the idle. I did have to Grind the dowel locator bosses on the intake to get the ports to align.
 
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