RvFNG76 wrote:
small block 360 2 bbl wanna go 4 bbl but havent nailed it down yet. The engine in this monster is untouched except for the egr being removed (plate slightly leaks) by previous owner. Another fun little deal now is speedometer jumps and goes nuts every once in awhile checked the gear in the tailshaft but it looks fine any ideas?
Exhaust manifold -- I need a picture of what you have to see if one of my spares will work.
2bbl to 4bbl -- there are adapters for mounting 4bbl carburetor on 2bbl intake manifolds. Suitability is so-so and performance is less than optimal. Also, hood/doghouse clearance is often an issue. If you go with an adapter, definitely use a marine bilge blower ... the adapter will put the carburetor deeper into the hot air pocket under the doghouse.
You're better off switching from a 2bbl manifold to a 4bbl manifold.
Before you do it, check total cost. You may be able, for a slightly greater cost, to go to a multiport EFI manifold and system instead.
Speedo jumps -- clean and re-lube the cable, with graphite powder. (Clean with a solvent, such as kerosene, followed by brake cleaner or acetone ... flush thoroughly with each.)
Otherwise, the speedometer instrument in the dash is dirty or going bad. They can be cleaned and re-lubed. Be careful, some solvent can damage them. Dish soap and lukewarm water is best, along with small brushes and a lot of careful effort. Rinse afterwards with clear lukewarm water, followed by a denatured alcohol rinse. Re-lube sparingly with instrument grease.
Look for clearly worn plastic gears. I may have a spare speedometer, depending on what style you have. Alternatively, there's places on the internet that can rebuild old instruments.
