85 caprice 400 stroker..problem after problem!

I have a 400sbc stroker in my 85 caprice.. if i punch it then stop at a stop sign, when i go to take off again it bogs down and wants to die out..also it gets hot real quick and runs real sluggish i have a bolt on flexfan on it which i was told would keep it cool but that hasnt worked..i had the same problem with my 350 engine running electric fans. what should i do?? i was told by the guy i bought the engine from to re-cam it because this cam runs better with a manual 4 speed..is that part of the problem???  

The cam is not going to cause overheating, what about that radiatior, water pump, and t-stat? What kind of carb do you have? Is it adjusted or calibrated to your engine, sounds like you may be lean. Hows the timing set?  

I was saying the cam because maybe that was causing it to run sluggish, i mean when i talked to my mechanic he told me how hot it was was acceptable for this engine. I have a 750 electric choke performer series edelbrock and yes it is adjusted. Everything looks fine but it gets sluggish after i put it to the test.  

When you stomp it do you see any black smoke come out of the exhaust.
How hot is it getting also what is the timing set at.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

Take and put a little bit bigger t-stat in it were it will open at a little higher temp and check your plugs and wires might have one fouling out when you stomp the pedal to the medal i had the same problem on my 85 chevy truck changed a few things and it ran alot better..  

you can try lighter springs on the metering rods If the cam you have is high in duration and has low vacuum, this is common to have a stumble  when you upsize the cam. What are the cam specs?  

the 400 blocks are famous for over heating becase of the big bore and thin walls but check your timing  

just curious... does it still have the radiator for the 305 in it????  or did you get the heavy duty cooling version and the proper shroud for the 350 models that came in police packages????? you may not have enough cooling area in the 305 radiator..

it has been a long time since i was under the hood of one of those.. but i have cured overheating problems on other full size gm cars by reinstalling the rubber flaps that connect the core support to the header panel...

these flaps catch all the ram air through the grill and force it through the radiator...

i have used black rubber/vinal roll matting from the hardware store to replace it with...

one more thing is are you sure of the rotation of the water pump and the fan... i don't remember when they went to reverse rotation stuff...

that cooling system was really designed to work with a 195 thermostat... there may not be enough cooling ability to keep the coolant below 210F...   if a 160 or 180F stat is installed sometimes they will go wide open.. that removes the start and stop or slow circulation of the coolant through the radiator core so the cooling fan and ram air through it can take the heat out...

some people put in nascar restrictors..  these are designed to restrict flow at race engine speeds.... 5500 to 7500 rpms...   ever notice that nascar teams change the amount of tape on the grill during the race... they are changing the amount of air into the radiator.. to try to control the temps...

can you   also inspect the radiator cap.. make sure the center button in the middle of the rubber seal is spring loaded tight against the rubber gasket... some are not... and those will not hold cooling system pressure.  replace them..

and how hot is it getting.. non contact infrared thermometers  are available at most parts stores.. starting at about 20 bucks...  decent ones at 40 to 60...  lets you know exactly how hot things are getting...   point and shoot... then you know...