Heats up on the highway

I'm a novice engine tuner here with a 327, cam Elgin e-919-p (408 lift 280 dur) & a Holley double pumper. It's not a combination I chose but what I got with the car. Trouble is it starts to run hot a freeway speeds after about 15 to 20 min on an average temp day of about 80 - 85 degrees. New radiator and high flow water pump don't help. Timing is set at 8 degrees at idle and 27 at full advance... I'm guessing I must be running lean from what I read in the various posts. I'd love some ideas on where to go from here.

it could be lean but 27 is a bit low . that rpm is it coming all in at ? how is the ex ? water speed may need to play with the pulley speed what is hot to you ?

What about your thermostat or lack of one? If you aren't using one the water can pass threw the radiator too fast and not have enough time to cool.
Ken

I'm not sure what rpm it's all in at - I'll have to check that with some help this weekend. A shop tuned it for me & that's what they said it was set to. It's not boiling over but it's hot enough to ping like heck with some load. I don't trust the temp gauge (it's flaky) but the infrared thermometer reads 200+ at the thermostat housing. I haven't checked the thermostat but I'll replace that this weekend too. Thanks!
Mark

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Originally Posted by Ken Thurm

What about your thermostat or lack of one? If you aren't using one the water can pass threw the radiator too fast and not have enough time to cool.
Ken

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yes and look at the cap to buy a good stat not a cheap one

Check the bottom hose if its spongey it will suck shut under steady driveing. Hope this helps..:D ...Francis

Did you not mention vehicle model and make, or did I miss it?

I remember a thread on Steve Buttita's TA forum, where a girl had this TA which was overheating. No one could steer her to a solution, and she ended up selling it on the cheap. New owner knew what the problem was before he even bought it... lower air dam was missing.

All good stuff for me to check this weekend - long hours at work this week. It's a '63 Corvette. I know they aren't the best for cooling but I've got a new Dewits aluminum radiator & new fan clutch in it and can't believe it should heat up at highway speeds like that. I did some sealing around the fan shroud too.

Ok guys... I had a chance to play with it a bit this weekend. Here's where I'm at: timing was about 10 or 12 degrees at idle without vacuum advance - I set it to about 8 degrees and it looks to me like the advance is all out at 32 degrees at about 3,000 rpm. Not the best timing light in the world but I think it's close. Vacuum is about 13 - 14" at idle. I moved the vacuum advance form the "timed port" to manifold vacuum as well. The lower radiator hose seems fine - I didn't see it suck down at high rpm when it was warmed up. Overall it seems to run much better and even a bit cooler. It's hard to tell if I fixed the heating problem on the highway since it's much cooler outside these days. I may have to wait for the next warm day to tell for sure, but so far so good. At least I'll wait until I see the problem again before I mess with the carb jetting. Thanks guys. Mark

my chevelle seems to be running a bit warm too. It reaches almost 200 on the hiway in the 90 degree GA days. BUT lately the weather has been only getting into the low 70s, and the temp guage is only showing 180 or so.

I guess I'll let it ride for now, and maybe replace the radiator come next summer.

I had a hell of a time conquering an overheating problem in my 64 C10 with a 350. Ultimately I discovered the water pump pulley was slipping on the shaft. Hell, I thought it was the alternator bearings squeaking... But now... the truck is sporting a two( 1" )core aluminum radiator, and a 8X12" oil cooler, 15" electric fan ( pushing ) on a 175 on - 185 off thermostat switch, and a 175 thermostat. ( oh and a new water pump ). Thing runs cool now!