I've often wondered about reusing gaskets....i've done some intake swaps within a month of each other and the gaskets looked brand new. I guess the issue is the compression they're put under? I just swapped my intake about a week ago and the intake that had been on it was there for about a year, and the gaskets still looked fantastic, they didn't even stick to the heads or intake. I did use new ones but i wondered about reusing the old ones.
Technically you could reuse your lower gasket. A couple issues though with that...
One the stock gasket does not have the same port size as a aftermarket gasket will have like the FEL-1250 or FEL-1250S. You will want the bigger ports with the 'bigger intake'...so you can actually flow what the intake wants to do. Don't let a gasket hold you back.
Second, you may not be able to reuse your upper gasket if you change intakes completely, they do not mix and match.
But then again, if you are just reinstalling the intake you have to do some work, it is up to you and the condition of the gasket.
the stock replacment kit Fel Pro MS93334 has gaswkets that are about 1.15 " x 1.90" as compared to the 1.20" x 2.00" of the 1250. If you can use tht, it's a lot cheaper and a much higher quality gasket than a normal 1250 and the same as a steel core 1250S gasket.
buy some long bolts that will thread into the block thrugh the bolt holes on the lower intake. I beleive 5" should be long enough. You only need 2. Cut the heads off.
After you are done laying your gaskets. Thread them into opposite corners of the block loosely and then lower the lower intake down them using them as guide rails.
Thread the other bolts in first then remove them.
Using this trick, i've never had an intake leak (assuming you lay the gaskets properly)
Tools: a good torque wrench is a must have item. A razor blade scraper that holds a single edge razor blade from Home Depot or Ace hardware is another handy thing. Get a Chilton or Haynes shop manual - you'll need it for the bolt torques and patterns. The intake manifold has an especially odd pattern. You'll need access to a timing light to set the timing after you re-stab the distributor. Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling. Put some motor oil on them when you put the line back together.
The A/C Compressor comes off with lines still connected. Mark all the electrical, smog and vacuum lines with tags to help you remember where to re-connect them. If you have a digital camera, take several pictures.
Whatever you do, don't skimp on cleaning the gasket surfaces. New gaskets need to seat against bare metal and not the residue left from the old gaskets in order to seal leak free. This is the most time consuming and tiresome part of the job. Look for little things that need to be replaced like the short hose from the thermostat hosing to the water pump, damaged vacuum lines and hose clamps that are rusted or broken.
Plan on cutting the thermostat to water pump hose, or removing the thermostat housing. Also plan on removing the distributor to get clearance to remove the intake manifold. Remove #1 spark plug, stick your finger in the spark plug hole and crank. When your finger gets air moving past it, stop cranking. Turn the engine until the timing marks line up with the pointer. Now you can pull the distributor out.
My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.
When the surfaces are clean, use weather strip adhesive on the head to manifold surface, and on the side of the gasket that mates to the head. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.
Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.
Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. Wala! no leaks, and no gaskets that shifted out of place.
Get a tube of anti-seize and coat all the bolt threads and under the bolt heads. That will help insure even torque when you tighten the manifold bolts. Plan on re-torquing them a after a weeks worth of driving
Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $2.74 per kit. The pintle caps fit either injectors with a pin sticking out the injector end or 4 with more tiny holes in the injector end. The following are listed at the Borg-Warner site ( http://www.borg-warner.com ) as being resellers of Borg-Warner parts:
Most of the links above have store locators for find a store in your area.
Use motor oil on the O rings when you re-assemble them & everything will slide into place. The gasoline will wash away any excess oil that gets in the wrong places and it will burn up in the combustion chamber.
Consumable items:
Upper manifold gasket
Fel Pro 1250 or equal lower manifold gasket set.
Short formed hose between thermostat hosing and intake manifold
6 ft 7/64" or 1/8" vacuum hose
2 ft 1/2" heater hose
1 1/2 ft 5/8" heater hose
Blue Silicone sealer
ARP antiseize or equal for the bolts
4 each 3/4" hose clamps (spare item in case the old ones are bad)
4 each 1/2" hose clamps (spare item)