SB COOLANT RETURN LINES

Any advantage of tapping an aluminum intake for better cooling while running an iron head SB with 11.5:1 on the street?

Not really
EDIT
I'm running 10.4 with W-2s 0n my street 416 and I
dont have any issues

At what level would it be good to tap the rear of the intake?
Center of the intake?

I dont know.. I'm at 625 hp for a stock 340
block and its been fine.. I think this is about
max hp for a NA engine

go to www.moparchat.com then scroll down & click on "circle track chat" then you will see Sanborns' cooling mods that are in a sticky at the top of the page. read thru it & see what you think. It'll take you a spell to get thru all of it.

If you have the means to do it I would do it, I don't believe its going to hurt anything. I have a 580ish HP W2 416 and I added the extra cooling lines. I don't have any back to back data but it certainly hasn't caused any problems.

I put the lines on my iron headed 11.5:1 374. Probably a waste of $100 in lines and fittings. I didn't notice any real difference.

IIRC, Chrysler claimed that pulling coolant from the center of the W-5 head was worth 15 HP. I beat the crap out of mine on th dyno and actually lost 5 with the coolant pulled from the center cylinders.


I guess I could have spent more time trying to understand why but didn't think it worth the effort. I capped the fittings off and let it go.

Seems to me, if you want the front cyl's to run hotter, take some coolant out before it gets to them, corollary then would also hold, if rear cyls are too hot, starve the front cyls of coolant. Why there is a difference in the first place, would seem to a better place to start, IMO.

edit, this assumes the primary coolant flow enters the head in the rear and moves forward until exiting.

My Indy headed 434 runs about 175° in the summer without any extra coolant lines.

I remember reading the same thing. But you lost power. Perhaps, to cool? No matter, we do what works and make no excuses or apologies.

I should have spent some more time with it on the dyno, but I was there to test other stuff. At lunch one of the guys at the shop asked how much power those hoses were worth. So I decided to cap them and find out.


That was in 1999 but IIRC, it seemed like unless I did some modifications to the flow of coolant, you could actually stall coolant rather than keep it moving.

I actually thought about moving the lines down to the timing cover but I felt like there was lower hanging fruit to pick.

I did with my W2s. Just seemed to me that pulling hot water out of both ends, rather than running the hot water in the back all the way to the front first, would make the temps more consistent throughout the head. Especially in the area of the center exhaust ports. Plus eliminate any air pockets in the back of the heads. No downsides, nothing but possible benefits? I'm going to do it.

When My dad ordered a comp cam for the 416 we built comp recommended a 4-7 swap. They didn't claim any power gains but one of the reasons was to move the hot spot created by 5-7 up near the front so the water can get out quickly as opposed to warming up that whole bank. So that alone seems like justification for the rear exit. IIRC he said the cylinder swap was easier on the crank as well.

416 small block with a 4/7 swap?
Who does the crank?

It's just a cam change, regular 4" crank.