287b heater not throwing much heat

took it all apart and cleaned the core fan works fine, just not much heat coming out of the vents. I have a manual heat selector dial- not sure if that is the culprit

You may have a shut off valve on your heater line ... you want to make sure that it is fully open.
See the attached diagram from my 242B ... that heater shut off valve is Ref. 3 in the diagram ... the valve is located on my engine. You may have something similar.

no shutoff that I can find on mine- the previous owner told me it used to produce heat. I am suspecting the heat control knob- it moves but i'm wondering if the part in the pipe is detached. Anyone tried to bypass that?

Did you check the actual radiator with it level and the Radiator cap off. Many folks have been fooled by those sight glasses with radiator down 2 jugs of coolant. That is always the first place to check. A full overflow does not mean the radiator is full. Then as stated above bypass the heat control valve for maximum heat. My friend opened up to change thermostat only to find it was missing. Start with these checks if you haven't already.
Simon C

Might be too obvious but how is the thermostat in the engine? If engine is not getting up to temp, something near 180ºF, the heater will not put out much heat. I see Simon C also mentioned thermostat but does need repeating.

Also what condition are the hoses in and any chance there is a kink in one of them?

Another thing is the heater core seal in someway to prevent cold air bypassing the core?

Yes as kshansen said a good check of the louver doors to make sure 1 door is not in wrong position would be good to check. Also a hose with a kink in it could cause the problem, but more often the hot or not hot water going to the core is the culprit. Let us know what you find ,Thanks.
Simon