i recently put a 65mm throttlebody on a stock intake, and headers also, i have 24lb venom injectors, 2 3/4 catback exhaughst dumped into single chamber spintech. after installing headers and throttle body, my car runs like crap, tried timing to 13 btdc, 0.98 on tps, new plugs and wires, vacuum is fine, should i check fuel pressure with this set up?  86 5.0 gt no mass air conversion  

I'm not an expert, but I know not having Mass Air and making changes to the air/fuel setup is a big no-no, especially the injector size.  Speed Density is still working on the set parameter that your injectors are 19 lb/hr units.  The TB and header upgrade will affect it as well, but not as much.  The only way around that is to get a custom chip burned for those exact parameters, or the better solution is to get a mass air setup.  That way, you don't need a custom chip burned everytime you do an upgrade.  

if you have an 86 it has a 58mm tbody stock, look for a take-off 60mm and put that on (save the 65 to when you change intakes) and put the 19lb injectors back in, you are no-way-shape-or form ready to change.