What is the reason that the rear coolant passages of the intake manifold gaskets are extreamly restricted? What whould it change to have unrestricted gaskets vs. restricted?

 

https://www.thirdgen.org/techbb2/sho...hreadid=118003
Maybe this helps?

 

nope, sorry tas but that don't help at all, they are just talkin about the hoses for the heater and stuff, my question is that on the intake manifold gasket in between the head and the intake manifold, why is the rear coolant passage of the gasket blocked off mostly and there is a hole the size of a pen or so in it, mind you not on all small blocks intake manifold gaskets but some like the ones specified for our engines, what is the difference between the two? Why would gm want to restrict coolant on some engines and not others?

 

well one of the reasons might be that our heater line is in the back of the engine insted of the front. Maybe if they didn't have it restricted a bit then cool coolant would only get thought half the block?

I'll copy this to the new cooling board for you.

 

Well the main reason why I asked is that when i built the engine I didn't like the idea of the restriction, so i want to napa went through all thier gaskets and found one with out the restriction, instaled it. Now I am going to change intake and do some misc. things and i am wondering which style to put back in and if i use the ones it calls for what is gonna be different? The engine is fine right now, never gets too hot or anything, just a question though, just wondered if anyone knew a scientific set in stone explanation of the difference.

By the way thanks for moveing the post, I forgot the cooling it down forum was here. Sorry to leave you guys out

 

anyone?

 

old post i still would like awnsered, if anyone knows.

 

An SBC does not need any coolant passages on the rear of the intake manifold. In fact there are possible advantages for not having the left and right cylinder head banks connected at all.
This is the reason that many performance manifolds do not have a rear coolant crossover provision, and why many racers either run a divider plate where the t-stat would go, or just plumb each cylinder head directly to the radiator via separate hoses.

The only purpose (besides the heater) would be to equalize pressure between the left and right banks and allow a high point where steam pockets could collect to keep them out of the cylinder heads. None of these purposes are efficiently handled by having the rear crossover passage, so many people just block the passage or do not run one.