You need a torque wrench for this man. Start all over with the heads. Get some silicone rubber gasket material, or some hi-temp RTV, the black tube. You need to apply this to the gasket and to several spots between the manifold, the heads, and the block.
When you replace the intake manifold, use the sealant. This has to be done fast... like as soon as you apply the gasket material, whether its silicone rubber or RTV gasketing. This is probably the issue in my opinion. Also, the way you torque everything down makes a difference as well. Its torqued down in a certian patern to assure a good crush and seal.
You will need all new gaskets.
Torque your headbolts to 44ft-lbs. There is 4 bolts across the top and then across the bottom. From left to right... 1 2 3 4 across top and 5 6 7 8 across bottom. Tighten in this order... 2, 7, 3, 6, 1, 5, 4, 8.
When you put on the manifold gasket, make sure to use the sealer.
Torque your intake manifold bolts to 6ft-lbs. If looking at the manifold from the front, there are 2 rows of bolts, 4 on each side. from front to firewall on left... 1 2 3 4, then from front to firewall on right 5 6 7 8. Tighten in this order... 4, 5, 8, 1, 7, 3, 6, 2.
Now, here is where it gets tricky.
Go back and tighten your headbolts up to 59ft-lbs in the sequence I gave you above. Then go back to the intake manifold and tighten those in the same sequence to 11ft-lbs. Now, go back to the head bolts and give them each a 75 degree turn in sequence. And then go back to the intake manifold and tighetn them down in sequence to 15 ft-lb... and then again to 18ft-lbs.
You have to do it this way to save yourself a lot of headaches.
make sure you RTV your valve covers, too.
good luck! and GET A CHILTONS to help you thru that ****.
