First off I want to say I know there are a lot of threads on engines running hot but I feel like I've been through them all and I've been chasing this problem for a very long time...years actually. So let me start by saying I've got a 1968 Firebird with a 455 out of a '71. I had this thing running at a nice 195 degrees on the stock '68 radiator and a dual electric fan setup I made from a shroud and electric fans I pulled from the junkyard. Sitting at a light during the SC summer and still running 195. I decided to make some suspension upgrades that turned into a few months of replacing frame rails, mounting brackets for the leaf springs, floor panels, and a new rearend. At the time I was using an Edelbrock 750 carb that I wanted some help tuning. After completing the suspension upgrades I took it to a local shop that was recommended for classic cars. I was using a toggle switch for my electric fans at the time. They forgot to turn them on and let the car overheated. Ever since then I've been chasing this overheating issue and just end up working on something else when what I try doesn't fix it. Below are upgrades or changes I made in an attempt to correct this overheating issue.
Radiator: BeCool Aluminum radiator rated for 700 HP
Fans: Derale shroud and dual electric fans
Waterpump: Replaced with stock one. Modified divider plate to bring it closer to the pump propellers.
Radiator Hoses: Good shape. Bottom hose has spring in it to prevent collapse
Radiator Cap: Replaced
Thermostat: 180 New, I've tried 160 as well
Fuel Delivery: Converted to EFI. Fitech 600HP
Alternator: Upgraded to high output Alt Tuff Stuff, in case EFI and fans were too much
Timing: 13 degrees BTDC
Distributor: Mallory with Mallory ignition coil
Plugs: New plugs and wires
Heater hoses: No heater core. Ran heater hose from back of heads to water pump. I also tried plugging back of heads and water pump.
Rockers: Harland roller rockers
Intake: Edelbrock Performer RPM
Fluid: 80% water 20% coolant plus water wetter
Block: I pulled the block and replaced the freeze plugs. Found a good amount of debris in the coolant passages. Cleaned out with water and air before putting new freeze plugs in
Head Gasket: Replaced but old gasket looked good
Temp Gauge: New AutoMeter gauge and monitored by Fitech. Both are electric.
Pressure tested cooling system and it holds pressure
Tried block tester to try and find exhaust in coolant but the bulb wouldn't really pull anything into the testing cylinder so fluid stayed blue. Not seeing any bubbles when radiator cap off.
The car seems to stay pretty cool just idling in the driveway but when under load, giving it gas it tends to heat up rather quickly. It may get warm just sitting idling but it takes awhile...like 20 min.
Am I missing something? I keep thinking about how at one time the original radiator and junkyard fan and shroud had the car running cool. Could the heads or block have cracked when it overheated? Would that be why it gets hot? I took it to another shop a few weeks ago that a buddy works at to see if they could figure it out. They couldn't figure it out either. Should I have the heads magnafluxed and checked for cracks. When I use the IR gun one side of the engine (driver side) is about 20 degrees hotter than the other side.
Any help here would be greatly appreciated. I'm dying to drive my car again.
Radiator: BeCool Aluminum radiator rated for 700 HP
Fans: Derale shroud and dual electric fans
Waterpump: Replaced with stock one. Modified divider plate to bring it closer to the pump propellers.
Radiator Hoses: Good shape. Bottom hose has spring in it to prevent collapse
Radiator Cap: Replaced
Thermostat: 180 New, I've tried 160 as well
Fuel Delivery: Converted to EFI. Fitech 600HP
Alternator: Upgraded to high output Alt Tuff Stuff, in case EFI and fans were too much
Timing: 13 degrees BTDC
Distributor: Mallory with Mallory ignition coil
Plugs: New plugs and wires
Heater hoses: No heater core. Ran heater hose from back of heads to water pump. I also tried plugging back of heads and water pump.
Rockers: Harland roller rockers
Intake: Edelbrock Performer RPM
Fluid: 80% water 20% coolant plus water wetter
Block: I pulled the block and replaced the freeze plugs. Found a good amount of debris in the coolant passages. Cleaned out with water and air before putting new freeze plugs in
Head Gasket: Replaced but old gasket looked good
Temp Gauge: New AutoMeter gauge and monitored by Fitech. Both are electric.
Pressure tested cooling system and it holds pressure
Tried block tester to try and find exhaust in coolant but the bulb wouldn't really pull anything into the testing cylinder so fluid stayed blue. Not seeing any bubbles when radiator cap off.
The car seems to stay pretty cool just idling in the driveway but when under load, giving it gas it tends to heat up rather quickly. It may get warm just sitting idling but it takes awhile...like 20 min.
Am I missing something? I keep thinking about how at one time the original radiator and junkyard fan and shroud had the car running cool. Could the heads or block have cracked when it overheated? Would that be why it gets hot? I took it to another shop a few weeks ago that a buddy works at to see if they could figure it out. They couldn't figure it out either. Should I have the heads magnafluxed and checked for cracks. When I use the IR gun one side of the engine (driver side) is about 20 degrees hotter than the other side.
Any help here would be greatly appreciated. I'm dying to drive my car again.