I have this 67 that some Einstein put a 429 from a 73 LTD
into. I'm in the process of trying to rebuild the engine and then trying to redo the body. I have a lot of ideas and questions but, first things first. I have long wanted to put a 429 into a P/U and for several years held onto an engine but, couldn't find a suitable truck,(I was looking for a 64). That's ok, I like the 67 body style just fine. When I got the truck it was running hot after about 15 minutes of driving. I checked the radiator and found bubbles, but no oil. There was no water in the oil either. Still... bubbles in the water and running hot made me think head gasket. So, after changing the head gaskets; still the same problem. Found out the water pump was sucking air through the gasket down by the fuel pump. Changed that gasket. No more bubbles but, it still ran hot. Got rid of the fan clutch and replaced it with a flex-fan. STILL ran hot! Now I've gotten to wondering if the heater not getting hot could somehow be connected. Sounds like a real longshot, but this is getting ridiculous. Now that I've pulled the engine and started to dismantle the body, nothing is out of the question as far as taking it apart and checking it out. If any of you out there like answering questions, look for me 'cause I got more'n a few.

 

If you are not gettingheat then i'd say your heater core is pluged up. If it like my 70 its easy to change if it is. As for overheating do some checks, start simple, check your coolant, water pump, t-stat things like that.

 

Yeah, I've checked,coolant level, thermostat, water pump,
and everything else I could think of. Even tried running
it without the thermostat. Made no difference. A thought
just occured to me (ow), could the OE radiator for that truck,
which had a straight 6, even though the radiator has 3 rows,
just not have enough cooling power for that motor? Sittin'
here I just realized that the S.O.B. I bought the truck from,
didn't change radiators. Anybody want to swap a 67 original,
3 row, for std trans. radiator that looks good and doesn't leak,
for one to fit a 429 auto? Hey, it could happen...?

 

Id say the heater not getting hot is probably connected somehow. After the engine gets hot, does the upper radiator hose get hot? Does either heater hose get hot? If so, just one or both? If the engine is getting hot, and the upper hose isnt, or not near as hot, then coolant isnt circulating. One, it could have an air lock in the water pump, and it cant get coolant to the impeller, or two, the impeller isnt moving coolant. Newer cars are a real pain with getting air locks in the system, and can cause alot of headaches trying to get them to break free. As for the impeller, Ive only seen it once, but we replaced a waterpump on a dodge van, 318 ci, due to a coolant leak and overheating. After putting it on, it overheated, like you describe. After rodding the radiator out, new thermostat, and putting a new tech on it(me), I pulled off the new pump, and found the impeller spun loose on the shaft. Apparently a bad batch made it to the store. Long shot on that. If the hose is getting very hot, youll probably find one heater hose hot, and the other cool. Wouldnt be surprised if you have a plugged heater core and too small of radiator thats probably plugged up.

 

 

See, that's what I was wondering about. Since the heater wouldn't
get hot, could it being plugged up cause the motor to run hot. I know
it sounded like a long shot but, sometimes you never know, you know?
I need to change the radiator out anyway since this one is for a std
trans. and the 429 has a C6. Any idea what size and how many rows are supposed to be in the stock radiator for a 73 LTD w/429 auto?
I'm not sure what you mean by "newer engines" but I have never run across an air bubble causing the water pump not to work. Not bragging or anything but I have replaced more water pumps than I care to think about. I have heard of the impeller problem before though, even though I've never seen it myself. But, turning wrenches is like anything else, if you aren't around it for long enough, you forget way too much about it, especially the small tricks that you only used once in a while anyway. The genius that put this radiator in this truck, put an after market oil cooler in front of the radiator with zip ties and ran the tranny fluid through that. Man, some people. You would think that a professional mechanic would know better than to do something like that and to make it worse, it was his own personal truck. I'd still be going by his place and cussing him out if the cancer hadn't got him, but hey, karma...
Anyway, thanks for the input and I'll pull the heater core and check that out since I'm going to strip it down to the frame anyway. Fix everything right once and be done with it.