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Big Block Cooling

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Old Dec 31, 2007 | 08:18 AM
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Default Big Block Cooling

I'm soon to install a RPM Airgap on my 496 build-up. I seem to remember in the past reading some info re. the potential cooling inadequacies of the big block engine especially for the rearmost cylinders. The remedy (as I recall) seemed to link coolant hoses from respective left and right coolant 'cross-over' point s (via tappings at the rear of the inlet manifold which the Airgap manifold has) through to the upper heater hose take-off on the front passenger side of the manifold and to a unplugged tapping on the front left side of the manifold. Is this a 'race only' modification? would it prevent me using the heater? does it work? any feed-back/comments would be appreciated.
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Old Dec 31, 2007 | 11:56 AM
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Default Big Block Cooling

I just put a shutt-off valve on the heater hose before it flows into the heater core. This keeps the water from ciculating throuh the core and overheating the interior . If you need the heat just turn the valve for circulation and the heat will drive out of the car. On my other big block I just plugged the heater hose outlets. Either way the cars run warm enough to keep you comfy except on the coldest days.
I barely have clearance on the airgap with Thunder 800 cfm carb and drop base K&N with 2 1/4" element under after market L-88 hood. I had to grind nut and stud off and stiil notice crack developing on top of hood. Good Luck!
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Old Dec 31, 2007 | 12:07 PM
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I think what he's refering to is the temp of the motor, not the interior of the car. You are right about running extra lines to the rear intake passage of the intake. That will help and will be business as usual. Just run it off your thermostat housing. You can buy them with extra fittings. You may not need to run extra lines but drill the holes and plug them for later installation if you end up needing them. I'm doing a 496 too and time will tell.
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Old Dec 31, 2007 | 12:46 PM
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Originally Posted by GRIZ73
I just put a shutt-off valve on the heater hose before it flows into the heater core. This keeps the water from ciculating throuh the core and overheating the interior . If you need the heat just turn the valve for circulation and the heat will drive out of the car. On my other big block I just plugged the heater hose outlets. Either way the cars run warm enough to keep you comfy except on the coldest days.
I barely have clearance on the airgap with Thunder 800 cfm carb and drop base K&N with 2 1/4" element under after market L-88 hood. I had to grind nut and stud off and stiil notice crack developing on top of hood. Good Luck!
Good idea. Something I had forgotten about (having disconnected heater due to leak) Re. clearance - even worse I want to make sure the carb sits parallel on mounting pad and level with engine (none seem to on Vettes) to minimise fuel level and 'welling over' issues. Have bought Moroso angled spacer - seems that it will now be approximately 2" higher than current Torker 2 & Holley DP - so yes L88 hood will be a problem. May end up having manifold milled level instead! and getting a custom hood laid-up!
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Old Dec 31, 2007 | 12:54 PM
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Originally Posted by BB72
I think what he's refering to is the temp of the motor, not the interior of the car. You are right about running extra lines to the rear intake passage of the intake. That will help and will be business as usual. Just run it off your thermostat housing. You can buy them with extra fittings. You may not need to run extra lines but drill the holes and plug them for later installation if you end up needing them. I'm doing a 496 too and time will tell.
I know I read about it somewhere (just can't remember where) I really need to have a look at cooling system flow schematics. I'm pleased you mentioned that rear 'take-offs' need to go to thermostat housing. I am hoping that as the block will be a fresh 'seasoned' and cleaned-out block with new Brodix ally heads the thermal and cooling efficiancy will better than stock. Because of clearance issues I will run without hood initially. Interior temperature - well we are going to 'cook' no matter what anyway
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