Cool That 351W

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Cool That 351W

Post by johnl » Sat Sep 18, 2004 12:59 pm

Cooling a 351W

posted by Quinn (aka Venom)

I just finished this one. The way I did it was based on what several other people told me to do and some pictures I had seen on the net. It's really quite simple.

Parts List (all 1/2" pipe thread)

* 2 ea 2" nipples
* 1 ea elbow
* 2 ea tees
* 6 ea barbed hose ends (fits 5/8" heater hose perfectly)
* 6 ea hose clamps

Cost was $65 including the $20 1/2" pipe tap. I used all brass fittings. I thought the prices seemed high, but after comparing with McMasterr-Carr, I found that it was within $5 of their price for all the stuff I got. The one that added up was the 6 ea barbed fittings at about $4 each. You could probably get tees and elbows with those things already installed and do it a bit cheaper. I didn't really take the time to shop around for the best approach. I just grabbed a bunch of stuff that would do the job and it did.

I drilled and tapped (1/2" tapered pipe thread) the 2 holes in the back of the intake manifold above the water ports in the head. On my Edelbrock Performer RPM intake, there are 2 small round areas that indicate the spots to drill. I centered the drill bit and drilled bigger and bigger holes until I had a 0.700" hole. In the driver side hole, I installed 1 of the nipples then the elbow. In the hole on the passenger side, I put the other nipple and then a tee. In the open end of the elbow and the 2 open ends of the tee, I put in 3 of the barbed fittings. I routed a short section of heater hose between the 2 sides of the manifold. The other tee (and other 3 barbed ends) got spliced into the heater hose connected to the water pump, not the one to the intake.

The 2" nipples raised everything just tall enough to clear the valve covers. They were also low enough to clear the air cleaner and throttle linkage and stuff. I lucked out on that one. I just guessed at the plumbing store. I don't know how it will work, but from everything I've heard, it should do pretty well. The number I've heard is a 20 degree reduction. If that's true, I should be fine. We'll see.

There are some pics on the Edelbrock site which should help clear up what's going on. If you go here, then look at the differences between the 289-302's vs the 351W, you should be able to see what the deal is. The back of the manifolds (firewall side) are on the right side of the pic. I have a Performer RPM which shows 2 flat bosses near the last sets of bolt holes on the right. Some of the other 351W manifolds have a passage in the manifold which is very clear in the pics. They are already tapped and have a passageway so you don't need to run a cross hose. Looking closer at the 289/302 manifolds, it *does* appear that they need this extra cooling as well. A couple of them have a similar passage and a couple have untapped raised bosses. So maybe I was a bit hasty in saying that this mod didn't apply to 302's. Looks like it might.

Check out some pics:





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Post by Stan » Sat Oct 02, 2004 7:33 am

I'm interested in doing this to my 351w / Edelbrock intake.
Is it necessary to splice into the heater hose line? If I don't will there be enough circulation through the block and heads?
Nice photos and explanation by the way--thanx!
Stan :?:
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Post by kw » Fri Feb 10, 2006 7:33 am

I have yet to hear just how much the running temp has dropped with this mod. Can you tell us your experience please? Also I would like to know how the hoses were ran. I understand that the sides of the intake are connected but where did the other hose run? Is is spliced in to the heater hose that runs to the top of the intake on the front? Or to hte water pump hose? I will be doing this very soon and would like to know how you ran yours. Thanks.

68Pony,69 351W, NP435, WH 6pt cage, PS, PB, 3.5 Trail Master lift, D44/gm disc, 4.10, Detroit, 9" 4.11, Lock Right, Edelbrock AFB, Hooker Headers, Pertronics, Accel super coil, tilt, MTR's, Xenon Brightlites on relays, 100A alt..................will work for Bronco parts

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Post by sk8board » Tue Feb 14, 2006 6:16 pm

I too am interested how this worked out for you? Have you noticed a temp. drop? Do you have any idea why Edelbrock did'nt do this in the first place?

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Post by john » Tue Feb 14, 2006 7:20 pm

here's anothe link to this writeup with a few more references. I did a couple searches on here and there's a few people who have claimed a 15-20 degree drop. sounds like a worthy modification if they get that much.

'74 w/ 5.0HO, C4, Atlas 4.3, hydroboost, ram steering, ARB, spool, Toyos!
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Post by Chuck66 » Fri Jul 07, 2006 7:51 am

This looks like a great mod and I would like to know what kind of temp improvement was acheived. I went a little differant way. I tapped the heater lines and ran them to the back end. I used a 12volt jumk yard fan and 2 F-350 trans coolers. This works realy well as long as the humidity is not to overbearing, but I do get 5-15 degrees over stock. I am running a half cab with the fuel tank as my bulkhead so I can run this either under the rig were the fuel tank was or in the back were it is now to keep the mud off. Not having the fuel tank under the truck is great!
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