Radiator Caps??

[Moparman01]

Ok i posted this question over on the CGLFC.com message board and Jim Shine answered it for me, but i thought i'd bring it up over here too, just to see what other opinions are. I've had an over heating problem with my 440 ever since i dropped it in the car, last Sunday i took the car to a show and the temp guage hit 220* while waiting in line at the gate. But i have found several problems that will contribute to over-heating issue with my set up and have fixed most of them. First off, i forgot to seal up the water jacket studs when i put the manifolds on the motor...all 4 studs were leaking anti-freeze. They are now sealed up real good, no more leaking. Second, i had a crummy little aftermarket flex fan on the motor, it was not sufficient enough to pull/push much air, so i got a big race fan from a buddy of mine which is much larger in diameter and huge blades, it might be a little bigger than a stock Chrysler fan. I also do not have a fan shroud...but i have ordered one but it won't be here for about 2 weeks. So after all, i started the car up yesterday and let the engine come up to temp with the radiator cap off to burp out any air pockets that may have been inside the cooling system , i have a new 160* t-stat in it too by the way, and once it hit about 170* the guage never moved from that point as it idled. I then put the rad. cap back on and took the car out for a short drive up the street, when i got back the temp was only up to about 180* so i let it idle for a while longer and it went up to about 195* or so, but like i said with out the radiator cap on it stayed at just above 170* with no problem. The cap thats on my radiator is rated at 7 lbs, everyone i've talked to says they run 16 lbs caps...does this make that big of a difference? Or is it just that i don't have a fan shroud? Also, i have a small (12" i think) electric pusher fan on the front of the radiator, that was in hopes to take place of the fan shroud for the time being. It's deffinatly not running as hot as it did before, it was a cool day tho in the low to mid 70's, i dunno what it will do when the outside temp gets into the 80's and 90's. Any thoughts on the radiator cap, or anything else would be appretiated!

[Chryco Psycho]

under pressure the coolant cannot boil until a higher temp , the cap will make Zero difference on the temp of the coolant , it just alters the boiling point
using a 160* T stat won`t help either , a 180 or 195 is better , once the coolant passes 160 the Tstat will never close , with a 180 it should close  & aloow the coolant longer to cool in the rad before cycling it back into the engine

[myk]

220 isn't considered overheating for a 440.  If anything, that's right where it should be.  Shrouds do make a difference, but I ran without one for years and I always held it at 220 or lower in low speed conditions.  Where's your timing at?  If there's a great amount of retard then the engine will naturally run hotter.  Are you running lean also?