I have a conditioned crawl space that needs to have a fire barrier on the foam block. Is there a product that can be applied that is not drywall. The house is finished and the access is 3 X 3 so something that fits down that would be best. Thanks for your suggestions

I have seen spray on fireproofing that might meet your needs.  Look for it on the internet.

Too bad you didn't know to put it on before the floor joists were in place!

If material cost is the overriding consideration it's hard to beat drywall for cost. Otherwise here are some choices from the pertinent paragraph in IRC 2006.

R314.5.4 Crawl spaces. The thermal barrier specified in
Section R314.4 is not required where crawlspace access is
required by Section R408.3 and where entry is made only
for service of utilities and the foam plastic insulation is protected
against ignition using one of the following ignition
barrier materials:
1. 1.5-inch-thick (38 mm) mineral fiber insulation;
2. 0.25-inch-thick (6.4 mm) wood structural panels;
3. 0.375-inch (9.5 mm) particleboard;
4. 0.25-inch (6.4 mm) hardboard;
5. 0.375-inch (9.5 mm) gypsum board; or
6. Corrosion-resistant steel having a base metal thickness
of 0.016 inch (0.41 mm).

The thermal barrier referred to above is the 15 minute, 250° temp limit, that can be provided by 1/2" gypsum board.