I have a newly rebuilt 1970 429 that ran cool and have recently had to rebuild it again and stroked it to a 532 and have not been able to keep it cool at a idle. The cooling system is the same as when the motor was a 429 (stock water pump, 2 core griffen aluminum radiator with a 16" electric puller)

The motor was stroked because i had a bad experience with a machine shop and had go with a different block or stroke it. I choose to go big!

The cam is a 292H comp cam and i had the timing lockout at 32 advanced when it was a 429 and didn't have a cooling issue. Now that it is 532 the timing is set at 0 TDC and i can't seem to keep it cool?

Does anybody have any ideas as to why it overheats and what to do about it?

 

I may be wrong, but I was under the impression that too little timing advance could cause excessive heat. Do you have your carb jetted correctly? Too lean can also make it run hot. Does it cool off when you get going 40-50 mph? If so, that's an indication that you just don't have enough airflow across the radiator with that electric fan. 532" is going to produce more heat than 429" no matter what, so you may just need a more powerful fan.

I have a 501" stroker with aluminum heads. I use an electric fan out of a Lincoln MK-VIII (popular with the mustang guys, flows ~4500+ CFM) with the stock radiator and water pump, and it is able to keep it cool.

 

The carb is a Holly 780 single feed. It does run lean. I have not had it on the road yet because i was told by the builder that the 780 was to small and was leaning out and not to run it until i get a bigger carb.

When he ran it on the Dyno he put a 950 HP to keep it from running lean.

What year Lincoln did your fan come off?

Unfortunately it has cost alot of money to build this motor twice and it's taking some time to purchase the right carb and a few other things.

 

I'm not sure exactly what year it was, but any Mk-8 will have one. At some point in the production run, they changed the shape of the fan blade to reduce noise, but they all flow very well.

I've actually got a modified Holley 750 on mine (dual feed though). Already had the carb when I had the engine built, and expenses were adding up fast (as I'm sure you understand!) and I didn't want to spring for a new 950 HP yet, so I opted to have my builder send the carb off to one of his circle track racing buddies to be worked over a bit. I don't know what all was done to it, but the choke has been removed, and I believe the boosters were modified a bit. I have 84/94 jets in it now, and it runs very well.

My understanding has always been that too small of a carb won't cause the engine to run lean as long as it's jetted correctly, it just won't flow as much air at WOT as the engine would like. Think of it like this: a 750 CFM at WOT flows as much as a 1000 CFM at 3/4 throttle, right? That 1000 doesn't run lean just because it may happen to be at 3/4, or 1/4, or any other throttle position. In any case, the carb does need to be jetted properly for the engine.

The single feed could be a bottleneck as far as fuel flow though. One alternative may be to swap float bowls from a dual feed carb.

 

I checked into rejetting but was told by a carb gurue that my carb could not be reworked to what the engine needs because it is a Truck Avenger? Did your fan come with a shroud? What kind of power does yours put out?

 

I am not an expert on the 429, and you might want to check in the 385-series forum, but is it possible the head gaskets were put on backwards? On the FE series (360/390/etc), if you put the head gaskets on backwards, water doesn't flow through the block to the back of the heads, and then forward again. This results in the engine overheating because the water flows from the front of the block directly to the front of the heads and leaves the back part of the block/heads hot.

Because everything else is the same, it's the one thing to look at.

 

I guess the Truck Avengers may be different than most Holleys then, but I'm no expert!

I haven't had mine on a dyno yet, and I wish I could afford it now! When I had the engine built, I was single, had just gotten back from Iraq, and lived in Army barracks. Now, I'm married, have a mortgage on a house, and am a full time student, so the truck is on the back burner.

I did take it to the drag strip a couple times last year. At that time, it was having some fuel starvation issues, and if I tried to shift it any higher than 5,000 rpm it would break up badly. It had cheap tiny headers and 2 1/4" exhaust piping. And, it still had (has... ) a 3.25 ratio open differential. With all that, it ran 14.0's. I've since resolved the fuel starvation and redone the exhaust (Hooker Super Comps into dual 3" piping), and it will wind cleanly past 6k RPM on the street now. Haven't been back to the track yet though.

I'll add that it did haul the bike and tow the Ranger in my sig 900 miles from Georgia to Texas with no drivetrain related issues. My goal in building the thing was a vehicle that would run high 12's on Friday night, and then tow a boat to the lake on Saturday morning.

 

Suggest you get a new carb guru. If the carb is running lean at part throttle or even wide open throttle, it needs to be re-jetted. The CFM rating on a carb refers to the amount of airflow that can flow through the carb. Fuel is then metered according to that airflow.

Using the displacement of the engine and RPM it is fairly easy to figure out the absolute maximum size carb that you should need. If you consider that your engine has a 100% volumetric efficiency (which it doesn't unless it is forced induction) then at 6500 RPM the maximum amount of air that your 532 can pump is 1001 CFM. Cut the RPM down to 5000 and that airflow number drops to 770 CFM.

Use a more realistic number of say 90% volumetric efficiency and that 6500 RPM number falls to 901 CFM and 5000 RPM falls to 693 CFM. Also these numbers also only apply to wide open throttle. Any part throttle flow will be significantly less.

Now I don't know how fast you intend to spin your engine, but I'm betting not THAT fast. There are people who will tell you that the numbers lie and you need a slightly larger carb than what the numbers tell you. That may be so and I'm not here really to debate that point.

My point is simply this: A carb flows fuel in relation to the airflow going through it. If it is running lean the problem is with the jetting. If your engine demands more airflow than what the carb will allow, it will not run lean. Your carb will reach a point of maximum airflow, but the fuel will still be supplied proportional to that flow. In order to run lean you would have to be drawing AIR through the carb without FUEL, which doesn't happen. If it's running lean, it's a jetting issue. You may need more carb for maximum power, but you do NOT need more carb just to keep it from running lean. If your carb guy tells you any different, find a different carb guy.

It is possible that your carb is suffering from fuel starvation, in this regard you may need to look at your plumbing or possibly the dual feed setup, etc. Thing is most engines make peak power at a given air fuel ratio, usually AROUND 12.5:1. If the carb is a 780CFM carb, you would think it would be designed to accept enough fuel for 780CFM worth of airflow. This would indicate to me that if it's starving for fuel then maybe your fuel pump can't keep up, not the carb.

Back to your original point. Get it jetted properly and get the idle mixture set properly and set the base timing to something conservative and it should not overheat. No reason to run locked out timing unless it's strictly a race vehicle. Mechanical and vacuum timing advances were created for a reason. They give you better economy and better power when circumstances demand. If it detonates under certain conditions with variable timing, then it is possible that you need to adjust the timing curves. There are tools to do this and still maintain the benefits of adjustable timing.

 

My carb originally came with a metering plate on the secondary side. That has since been replaced with a kit that allows me to adjust the mixture by replacing jets just like on the primary side.

I don't know for sure, but I remember hearing somewhere that the Avenger type carbs were different than most Holleys, and therefore a lot of the parts out there (metering plates/blocks, float bowls, etc..) that can easily interchange between the other carbs may or may not work on the Avengers. I wonder if that's what his carb guy was referring to, as in difficult to re-jet?

 

The fuel pump is a Holley mechanical 100 GPM. I was told the Truck Avenger could not be converted to a dual feed and is very limited as far as tuning goes? My problem is i can't keep it cool enough to even drive it. Do you think it is a carb issue? It didn't run hot when it was a 429

 

I think if it was a fuel pump issue, that may cause it to run lean at high rpms, but there's no reason a functional mechanical fuel pump couldn't provide enough fuel for that engine to at least 4,000 rpm.

I would say at this point that it's most likely a carb issue. If the carb was tuned perfectly for a stock 429, it will be too lean on a 532 with a 292H cam. I had to jet up big time when I went from a stock-ish 460 to my current engine, even with the same carb. Now, whether or not your carb can be tuned to the degree your engine requires is what we need to determine.

 

Have you tried talking with the cam manufacturer? What about Holley? I'm sure they have tech lines and would be more than happy to discuss it with you. They might could give you some good info regarding recommended base timing and jetting. It won't be perfect but it would be a good start.

 

That's what I'm thinking, why the retarded timing on the new motor?

 

Put the timing somewhere around 14-18 initial and depending on heads 32-40 total. The carb will work ok but wont give you the upper rpm hp your motor should make. My truck has a stock mid size radiator (not the super cooling one) with a flex fan and no shroud. Timing is your major issue.

And Staysbroken do you have any pics of your truck? You should easliy run 12s with your set-up and be fully streetable. Ive been low 12s with a 466 irons heads 850DP and an XE284H. Supercomps with 3" exhaust and 3.70s. 4200lbs

 

I don't have any pics up now, but I'll try and get some up in the gallery this week. I think at this point, my biggest bottleneck is the rear end... it would definitely respond well to more gear, a locker, and some slicks. Have you done anything special with your rear suspension? Traction bars?

Looks from your avatar like you're running slicks. Did you need to upgrade your axles and/or 3rd member case, or do the stock parts handle them ok?