My question is....I have Afr 165 heads and there are rear coolant passages on the back ofthe heads,but on my edelbrock rpm air gap intake there arnt any. Is this going to cause a leak? I didnt have a leak when the motor was running. But I cant see how this wont cause a problem.
thanks,
Pat
83-84 Ford Factory Aluminum 4bbl Intakes
Edelbrock F28
Edelbrock Performer 289(mid-90's and older non-color "Made in USA insignia")
Edelbrock Performer 302
Edelbrock SP2P
Edelbrock Torker II
Professional Products Power Plus 'Crosswind' (RPM Air-Gap version)
Professional Products Power Plus 'Hurricane' (Vic Jr Version)
Professional Products Power Plus 'Typhoon' (Perf RPM Version)
Weiand Action Plus
Weiand Stealth
I don't think any of the Holley and Offy intakes have the water crossover. Be careful when selecting the Edelbrock Performer intakes when looking for that rear passage. It's more or less a hit and miss for some reason but I do know that all the older Performers did have the water crossover.
As Sleeper said, it's because the same head casting is used for both sides of the motor. There is really no benefit of having a rear coolant passage. The water enters at the bottom of the block and works it's way up to the heads. then out the front through the thermostat. Having a rear passage doesn't really give the water anywhere new to go. Once the pressure equalizes in the cooling system, the water in a rear passage would pretty much just stay there.
As Sleeper said, it's because the same head casting is used for both sides of the motor. There is really no benefit of having a rear coolant passage. The water enters at the bottom of the block and works it's way up to the heads. then out the front through the thermostat. Having a rear passage doesn't really give the water anywhere new to go. Once the pressure equalizes in the cooling system, the water in a rear passage would pretty much just stay there.
I've been told by a very reputable machinist friend of mine that crossing over and then using a T to connect the rear tube up to the thermostat housing is worth a few hp, because normally #4 and #8 cylinders run hotter than the other six. That T setup is supposed to better balance the coolant temperature to the rear cylinders. I've run the setup before, never noticed any difference of course, maybe a dyno could detect the change, who knows.
But as you said, just using the rear cross-over by itself probably wouldnt do anything.
I've been told by a very reputable machinist friend of mine that crossing over and then using a T to connect the rear tube up to the thermostat housing is worth a few hp, because normally #4 and #8 cylinders run hotter than the other six. That T setup is supposed to better balance the coolant temperature to the rear cylinders. I've run the setup before, never noticed any difference of course, maybe a dyno could detect the change, who knows.
But as you said, just using the rear cross-over by itself probably wouldnt do anything.