Engine HELP!!!!!!!

I am on my third motor this year, 5 distributors, 3 radiators, 3 different cams, 4 sets of heads, new caps, new wires, new lifters, several different sets of lifters, valve springs everything, and every time, my engines won't time where they are supposed to and overheats almost instantly..... what can i do i am sick of setting on the sidelines with blown up over heating untimed race cars.... They have been a 355 a 404, now a 358.... with different combos of 202 and 205 heads 480 to 535 lift cams.... holley 650's and 750's.... stock and victor jr. intakes i'm lost!!!!

Junk timing light or balancer ?

Are you using a timing light with a dial? Does your balancer have a mark at 34 degrees or just top dead center.Is your distributor locked? I have heard of countless engines blowing up because of somebody setting the timing light at 34 degrees and checking the timing at the 34 degree mark which gave them 68 total advance.Also are you checking your timing at full advance by raising the rpm untill the timing quits advancing>

I have seen this several times in cars that use an MSD box. The problem is the little black plug on your green and purple wires to the dizzy pick up are reversed. Simply unplug the plug, flip it over and plug it back in. So if you were green to green and purple to purple you will now be green to purple, or vice versa. You will have to force it together but for one reason or another something in some boxes got wired up incorrectly internally.
You know when you have this issue when you try to time it with a dial light and you can turn the dial from 0 to 60 and the mark on the balancer never moves. The car will idle like a pig, be VERY lazy when you try to free rev it, will pop and spit under load and just about immediately overheat with glowing red exhaust.

UMMMM.. green to purple and purple to green is the CORRECT way to wire a MSD.

Dealt w/ the msd wiring yesterday purple/black goes to the green. Black/orange goes w/ the purple.

Here is a link see page 12
http://www.msdignition.com/pdf/WDTN_pn9615.pdf

i understand what c10 is saying but if nothing is wrong w/ the box this is how its to be wired according to MSD. Some boxes for some reason or another have the polarity reversed and you have to switch them. if you suspect its the msd box try calling MSD or reading on the link i posted alot of helpful info on that.

thanks to everyone who helped, it must have been in the msd box because we put a regular distributor in it and it fixed the problem, didn't know those could cause those problems, appreciate the help though, gotta learn somehow just an expensive lesson haha, thanks again!!!

To check a msd box for proper hook up you can just try the wires to the dist both ways and you want to run the way that is the most retarded I think. I have it written under my dash flap and I have two wires to jump this and test mine each time I install a msd dist for the first time.

the mix up is on the dist pick up