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Discussion Starter · #1 ·
ok, so we are STILL fighting an overheating issue, and theres a bad bushing in the right rear trailing arm, and the trans isnt quite right yet, BUT....we did a short,top of 2nd to 3rd, 2000 rpm to 3000 rpm at 1/3 throttle blast last night with the new 461 ( 454, +.030, 9.5 compression,292/595/108,750carb,rpm intake,2" headmans,roller top, heavy port&polish big valve ovals,2800 stall,3:73 gear. )....WOW.thought the front end was gonna come off the ground or the rear diff would scrape the pavement--YIKES! thats a LOT of power. and totally worth everything we gone through so far ! cant wait for the first full throttle, idle to 5800rpm roll on !!! *zzzzzip, BOI-OI-OI-OING...* if you know what i mean....:banana::Banane08::toocrazy:
 

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ok, so we are STILL fighting an overheating issue, and theres a bad bushing in the right rear trailing arm, and the trans isnt quite right yet, BUT....we did a short,top of 2nd to 3rd, 2000 rpm to 3000 rpm at 1/3 throttle blast last night with the new 461 ( 454, +.030, 9.5 compression,292/595/108,750carb,rpm intake,2" headmans,roller top, heavy port&polish big valve ovals,2800 stall,3:73 gear. )....WOW.thought the front end was gonna come off the ground or the rear diff would scrape the pavement--YIKES! thats a LOT of power. and totally worth everything we gone through so far ! cant wait for the first full throttle, idle to 5800rpm roll on !!! *zzzzzip, BOI-OI-OI-OING...* if you know what i mean....:banana::Banane08::toocrazy:

If you are running the stock shroud and fan then I would guess you have a wrong temperature sender that isn't calibrated for your gauge...............
 

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Discussion Starter · #4 ·
didnt have a shroud, and theres tiny little 14 inch fans--my guess not enough cfm, over not enough surface area. the radiator is a new "HD" 4 core but the old style brass and copper, and the car runs fine for the 1st 40 minutes or so then slowly just keeps creeping up till its so hot i need to shut it off. ( i usually get scared around 225 degrees or so, thats just too high even for cast iron heads. ) i need either a proper shroud/mechanical fan, bigger kick *** electric fans with proper shrouding, a 4 core aluminum radiator, or any/all of the above....but man oh man its still worth it, what a rush that short little squirt was !:banana:
 

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didnt have a shroud, and theres tiny little 14 inch fans--my guess not enough cfm, over not enough surface area. the radiator is a new "HD" 4 core but the old style brass and copper, and the car runs fine for the 1st 40 minutes or so then slowly just keeps creeping up till its so hot i need to shut it off. ( i usually get scared around 225 degrees or so, thats just too high even for cast iron heads. ) i need either a proper shroud/mechanical fan, bigger kick *** electric fans with proper shrouding, a 4 core aluminum radiator, or any/all of the above....but man oh man its still worth it, what a rush that short little squirt was !:banana:

Without the correct shroud you're just urinating in the wind as the shroud guarantees the entire core is used. Get yourself a shroud and a 7-blade clutch fan and your heating problems will vanish.

The engineers who design these cars KNOW what they're doing but down the road well-intentioned uh "experts" start removing the factory parts and then wonder why their cars runs like crap. If you'll notice, Ford, Chrysler, and G.M. ALL run full size fan shrouds to ensure the entire radiator core gets sucked thru. Hell, even my 1953 Ferguson TO-30 tractor has a full size fan shroud which tells you the manufacturers know something about cooling engines. Electric fans can be used but they too MUST have full size fan shrouds.
 

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Then there's something else you need to know. A 14" electric fan does NOT pull air with it's entire 14" diameter as the inner 1/2 doesn't pull any air at all. So a 14" fan actually pulls air from it's outer 116 square inches. Two of those fans would then equal 232 square inches of area but the 18" X 26" core has 468 square inches of area. See the problem? A stock 7 blade clutch fan pulls about twice as much air as any pair of electric fans. Powerful electric fans can be used but because of their current draw a large capacity alternator must be used that is capable of running them which is why the '84's and later run 200 amp alternators.
 

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If you are running the stock shroud and fan then I would guess you have a wrong temperature sender that isn't calibrated for your gauge...............
I ran into the wrong sending unit issue. I snapped the spade connector off the original and bought a Napa replacement which read a lot higher. I used an infrared thermometer to check and bought an original off a guy that stock piles corvette parts up here.
 

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I ran into the wrong sending unit issue. I snapped the spade connector off the original and bought a Napa replacement which read a lot higher. I used an infrared thermometer to check and bought an original off a guy that stock piles corvette parts up here.

The '68 thru '71's use a sender that only works for the "green face" gauges and it isn't listed in any of the aftermarket catalogs so you must get it from one of the Corvette-only parts suppliers.
 
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