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Tharf is my hero :read:
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Discussion Starter · #1 ·
I bought Fel-Pros with the ports blocked off for the rear water ports. I also had a set of spare intake gaskets left over from a friends rebuild without the ports blocked off. I saw that the intake (Edelbrock Performer TBI) is designed to flow water through there because thats where one of my heater lines plugs in just behind the distributor. I went ahead and put it all together with the ports open but now friends are telling me it may overheat and I should have restricted the openings.

Can anyone explain further cuz im crazy confused on this one and im getting ready to start pulling the old 350 out this week. I wasnt planning on pulling any of the old 350 out to see how it was but it would seem to me if the ports are both open on the heads and intake then water should be flowing through them right?
 

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I don't see why you would need those ports blocked off. I also bought a set of fel-pros when i did my intake gaskets but mine were open so basically you could install them on either side. I know the vortec intake (and i suspect your stock tbi intake) doesn't flow coolant through the back of the intake. Maybe thats why those fel-pros don't have the holes. I can't see how running with those ports open on the back would overheat your truck unless there is somehow a connection directly from around those rear ports to the radiator. In that case coolant may not circulate properly in the engine. But of course this is not the case. I guess there is the possibility that the water pump could just pump coolant right into the upper part of the block and up through those rear ports and back into itself. I doubt this is the case though. Edelbrock probably put them there for a reason so i would definitely not worry about it.

In fact this may help keep the rear of your engine block cleaner internally but continuosly circulating the water. I know when i pulled my intake off there was a ton of shit built up right around those rear ports where the vortec manifold had them blocked off.
 

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Tharf is my hero :read:
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Discussion Starter · #3 ·
Your thinking is exactly the same as mine. I just assumed flow through there would be better. Especialy since I have a heater hose connection right into the back of the manifold into the area where they supposedly want me to block them off. Ive been reading a bunch of stuff on FSC today about it and nobody has a clear cut answer as to if they are required and what the consequences are if you keep them open versus closed.

I put everything together with them open but now im trying to decide if I should pull the manifold back off and close off the ports before I install the new engine next week.
 

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Tharf is my hero :read:
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Discussion Starter · #5 ·
Im gonna keep it open for now and I guess if there is any problems with cooling later ill close em up. I gotta figure a 383 is gonna generate a little more heat anyway.
 

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I think i'd keep em open too just to save the hassle of changing intake gaskets for these trucks. Good luck with the swap.

If you get a chance, could you snap some pictures. I'd like to see this heater hose setup you have going on in the back. I've never heard of such a thing. Would be interesting to see.
 

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Tharf is my hero :read:
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Discussion Starter · #7 ·
I have a bunch of pics of the buildup here
http://www.gmfullsize.com/forum/showthread.php?t=80128


I officially start removal of the 350 from the truck this sunday as weather up here in New England just went to 70 degrees after 6 days of nonstop rain. Sux when your truck is 2 feet too tall for the garage.
 

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hey i changed my intake on my tbi and i removed the blocks for the coolent passages on my tbi intake the coolant can flow from the front to the back undre the intake runners and i had major buildup there but after sandblasting it opend back up and i asked my mechanic ans he said that to his knowledge that the ports being open would only help flow and keep it cooler... i have right now 1k miles on the new gaskets and i have not had my temps get above half way between the left side of the water temp gauage (i cant remeber the numbers but i have not gone over 200* and i have the stock thermast ) so i would leave it because i have in the past would hit 200* as the thermast opened and then it would settale back down the same range i have now but i sit everyday in the hot MIami Sun at 2:30 for fifteen minutees and not even move and stay below well below 200*
 
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