sbc 350 temps

[Smitch320]

As you all know, I have a new gm goodwrench 350 crate, I have a edelbrock intake, 1406 carb, and sm465 trans. I had a 4.3l V6 in it previously. I am still running the radiator out of the v6 (no ac hooked up).


I run at about 210 or a needle past 210 on my gauge.

How can I get it to run cooler? like 190-195?

 

[HotRodPC]

Bigger radiator.

 

[Smitch320]

Thats next on the ever growing list of truck parts, thankfully my heavy chevy is not my DD. I drive it about a mile or two monday through friday. It has never gone a needles width beyond 210 but I just want it to run cooler in general.

I have AC but it hasnt worked in years. I have it mounted but not hooked up. I want a radiator that can handle the AC if I ever do what to hook it up.

Any suggestions?

(someone I know suggested a junk yard rad. but that just makes me nervous for some reason, I would hate for my hard earned money to rest in the hands of a junk yard radiator)

 

[HotRodPC]

So do you have a single core or 2 core radiator now? I think a 3 core is standard for Small block and AC. Big Blocks come with a 4 core with AC that I"m aware of. If you want the extra cooling, 4 core, or an aluminum 3 core will do that job. Many times the 3 core aluminum will do that same job as a 4 core brass/copper/plastic radiator. Reason being, the coolant strips are closer together, so there is more coolant to the system, and they do still discipate the heat being aluminum. I'd like to go with a 3 or 4 core aluminum myself, but I don't see 4 core aluminums. Running at 210-220 is a bit warm but should be OK so long as you have coolant in your motor and a 14lb pressure cap or so. The coolant, and the pressure raise the boiling point, so your coolant won't boil away at 212 degrees. If you have weak or tired head gaskets though, they might not like that prolonged 210-220 temp without giving up. My 454 with a 4 cores runs 210-215 on summer days on the freeway. Never been a problem. Of course that's the OEM gauge telling me that, so it might cooler than 210, could be higher too.

 

[Smitch320]

I want to say a 2 core, but it very well could be a single. My head gaskets should be fine since I have all of 284 miles on them. I have been told that as long as I do not go over 220 I am fine, but I do not want to run a risk. Ya know? I plan on keeping this truck and do not want to mess it up, it was my first car and now its more of my project truck since I have a car now.


Thanks for all of the help. I am remotely new to all of this and young, and don't come from a dad who is a car guy, thats why I turn to you guys for help.

 

[HotRodPC]

I agree. Keep it under 220 for now, you'll be OK. For an 86 or older, or actually better specify NON Computer controlled, 180 is sufficient and 195 will work too. I run 180 Thermostats on non computer controlled engines and 195 on Compter controlled engines. Many times ECM PROM chips are programmed to not go into closed loop operation until they reach 190 degrees. So if you're hanging out running 180, you're really not getting the benefit of the ECM.
Yeah, I'd say you're probably running in the 10's for compression then. As crazy it might sound, you might want to consider going with a bigger cam with a little lope or some vavle overlap to it. By doing this, you'll be bleeding off some of that compression and be able to run the lower grade pump gas. I can't remember all the cam grinds I"ve ran in the past, but I remember a couple. 1 was a .525 lift can, durations was 3 something. Also ran .505 lift .310 duration cam, and the one I think I ran that was still single valve springs was a .485 lift 280 duration on a 112 lobe center. Didn't have alot of lope to it, but it bled off enough to run 93 octane leaded on a 10.5:1 motor.

 

[crazy4offroad]

Make sure your carb isn't running too lean, which can make it run hot.

 

[HotRodPC]

Make sure your carb isn't running too lean, which can make it run hot.

As will to far advanced timing.

 

[crazy4offroad]

I know for a fact if the idle circuits get plugged in that Edelbrock carb some people try raising the idle adjustment to compensate but it's running so lean the temps shoot up past 200. So if you're not running a good fuel filter, or running one of those glass "cleanable" filters, throw that bastard away and get a good AC Delco paper fuel filter, the glass/screen ones let a lot of trash through. Also if you think it's possible the idle circuit is plugged, you need to take the top off the carb and hit the primary jets with compressed air to clear them out. You might be able to take out the rods using the little covers for them without taking the top of the carb off, and blow the idle circuits out if your air nozzle is the kind with a long tube on it or the kind you can put a piece of vacuum tube on it.

 

[Tyger13us]

I know for a fact if the idle circuits get plugged in that Edelbrock carb some people try raising the idle adjustment to compensate but it's running so lean the temps shoot up past 200. So if you're not running a good fuel filter, or running one of those glass "cleanable" filters, throw that bastard away and get a good AC Delco paper fuel filter, the glass/screen ones let a lot of trash through. Also if you think it's possible the idle circuit is plugged, you need to take the top off the carb and hit the primary jets with compressed air to clear them out. You might be able to take out the rods using the little covers for them without taking the top of the carb off, and blow the idle circuits out if your air nozzle is the kind with a long tube on it or the kind you can put a piece of vacuum tube on it.

true,, but i also know that 1406's are jet and roded really lean.
the rods are 75x47 with 98 jets! way to lean for a 350 crate motor. they work great for a 305 motor...
1405's (70x47 and 100 jets) are jetted to rich for even my 400hp motor,, as for the case of the 1406 carb,, id do a rod change to 70x47 and then it wont need a jet change,,the only in-between size is a 73x47 rod and i find its still to lean for a stock 350 crate motor,, and set the timing 10-12 degs and check to see that it dont get 60+degrees of advance 50 is plenty and some will like 55 degs max....
those 2 things right there will make it run really hot even if the rad is sub par..

 

[Tyger13us]

quick and easy

And while im at it?
the fastest and easiest way to clear out the idle circuits in an edlebrock carb is to remove the air mixture screws and use an air compressor and blast the air through the mixture screw holes,, cleans them right out..
then seat the mixture screws and back um out 3 1/2 turns each,, fire the motor and give each screw a half turn in,, if it slows down back it back out to 3 1/2 and try going out a half turn,, no difference go back to 3 1/2 turns out on each side......

ive done alot with 1405's and 1406's and they seem to love 3 1/2 turns out,, unless some one has screwed the mixture screws in to far past seating...

 

[Boone83K10]

I will go ahead and mention it but could it be that the new sensor in the 350 reads at different ohms than your "v6" gauge, therefore giving you a higher reading than the actual temperature. just another nut thrown into the pile there for you to think about.

 

[GreaseDog]

Why do you want it to run cooler? 210 is right about where they run from the factory.

 

[Driver4r]

true,, but i also know that 1406's are jet and roded really lean.
the rods are 75x47 with 98 jets! way to lean for a 350 crate motor. they work great for a 305 motor...
1405's (70x47 and 100 jets) are jetted to rich for even my 400hp motor,, as for the case of the 1406 carb,, id do a rod change to 70x47 and then it wont need a jet change,,the only in-between size is a 73x47 rod and i find its still to lean for a stock 350 crate motor,, and set the timing 10-12 degs and check to see that it dont get 60+degrees of advance 50 is plenty and some will like 55 degs max....
those 2 things right there will make it run really hot even if the rad is sub par..

ive heard that 30's is about the most a person would want to be at full advance. And about 6 advance at idle.

any more and it throws your spark off way to much.

 

[Tyger13us]

ive heard that 30's is about the most a person would want to be at full advance. And about 6 advance at idle.

any more and it throws your spark off way to much.

I would agree with ya if it was a calif smog motor and had to be smoged..

that would be 36 degs total mechanical advance and then the vacuum advance would be hooked to manifold vacuum for the rest of the advance to the dist because the motor would run lean by calif standards and would need alot of vacuum advance to burn the fuel..

a lean mixture takes longer to burn and a rich mixture burns faster.....

6 deg base timing for a crate motor 350 is way too retarded 10-12 would be about right.......... and he will be running an aftermarket carb also.....