New here, thanks for your help.
I have a '68 Bird convertible and just had a 400 rebuilt and installed. I have tried to keep everything as close to stock as possible, with the exception of the RAM AIR 3 headers I put in. At idle, the car heats up close to the point of boiling over, but keeps cool enough (180-190) when moving and at night when the outside temp is cooler. I've replaced the stock 5 blade fan with a steep pitch 6 blade fan (no clutch) and made sure the fan shroud was well sealed. The water pump is new, as is the reproduction 4-core radiator, so I don't suspect a problem there either. I am thinking it might have something to do with the RAM AIR manifolds, which are much bigger than the originals. Anyone have any experience with those, or any other thoughts on the reasons for the heating up?
Thanks,
Pete

I can almost guarantee it isn't the exhaust manifolds. If anything, those manifolds will let the hot gases escape the motor easier, which, technically, may make it run cooler. I would check the thermostat first. Go install a 160 stat. Make sure the fan is fully inside of the shroud for it to be effective. They sell spacers to move it forward if you need them. Lastly, add one bottle of water wetter, it has been proven time and time again to lower temps by 5-10 degrees. All the stuff I told you here is dirt cheap too.

160 stat= 10 bucks
spacers for fan= 15 bucks?
water wetter= 10 bucks

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1994 Z28 Black heads/cam th350 drag car
1995 Z28 Teal 'Vert bolt-ons 6-speed cruiser

Thanks. I replaced the thermostat and added a bottle of Wetter, didn't have time to install the spacer this weekend. When I took the car out, I did notice a small difference, but it still heats up into the 210-215 range.It's been hot up here (about 95 degrees) and maybe that's part of the reason.

About the fan spacer: the instructions for the flex fan I installed previously said that the fan should be placed about half way into the shroud. As it sits now, it is about 6 inches from the radiator. If I put in a 2 inch spacer, the fan will still be 4 inches away, but will be all the way inside the shroud. Do you see any problems with that? Is there a reason the fan needs to be half way inside the shroud?

Thanks

No, as long as it is inside the shroud it should be fine. How is the timing on the motor? When is the last time you checked that? Also, how accurate is the guage?

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1994 Z28 Black heads/cam th350 drag car
1995 Z28 Teal 'Vert bolt-ons 6-speed cruiser

The timing is advanced about 10 degrees and the gauges are brand new Sunpro, so probably they should be accurate. Is there any other way to verify the actual temp of the engine?

You could buy an additional mechanical guage that plugs into one of the intake manifold plugs and compare the results. If the motor is running lean it will run hotter. How do the plugs look? If they are a chalky white it is too lean. You can retard the timing a bit, and fatten up the air/fuel ratio with a jetting change. Performance will suffer a bit though but it should bring the temp down.

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1994 Z28 Black heads/cam th350 drag car
1995 Z28 Teal 'Vert bolt-ons 6-speed cruiser

Hmm.....are the headers coated? If not, buy several rolls of header wrap, that may be the problem. Also, check the thermostat, even if it is new, see if you or someone else put it in backwards, its a common mistake.

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2001 Z/28 6speed. TSP 231/237 598/595 112 cam, PRC .660 lift valve springs, titanium retainers, TSP 7.4 hardened push rods, Lid w/ Amsoil filter, Longtube headers, TSP true duels, richmond 4.10 gears, SLP maf, LS2 timing chain and gear set, Clevite rod and main bearings, ARP rod bolts, Power bond 25% UD pulley, Custom tune by RPM performance, BMR subframes, BMR LCA's, Edelbrock TQ arm, BMR panhard bar,315/35/17 MT ET streets on black ZR1's... 395 rwhp 381 rwtq