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ANOTHER Engine Choice

greatguy57078

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Bronco Guru
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Jul 15, 2006
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Ok. I have two motors to choose from for my Bronco. I have a rebuilt stock 5.0 roller short block. I also have a '69-70 351w rebuilt short block. The 5.0 of course is a roller block, while the 351w is not.

This 351w block has TRW pistons, CompCam RV cam, Eagle I beam rods, ARP fasteners on the crank,rods and mains.

I have a choice of two sets of heads and intakes. I have GT40 intakes for both blocks, but the GT40 Lightning intake for the 351w has the ports matched to a brand new st of GT40X aluminum heads. These heads are bare and I have been looking for what it would cost for the kit to put them together.

I also have a set or rebuilt GT40 cast iron heads. This will be my daily driver and will see more street time than trail. I am also running a new NV3550 with 33 inch tires and 3.5 gears (for now). That being said, which would you choose........and why??
 

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greatguy57078

greatguy57078

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The GT40 cast iron heads are supposed to add 40 HP and the aluminum GT40X heads are suppose to be 65 added HP. THe GT40s are complete and ready to go, while the GT40X heads are bare.

Ford Racing used to sell the kit apparently but has now been discontinued. So ... how much are the aluminum heads going to cost to put together? %)
 

broncnaz

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May 22, 2003
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24,342
Id also go with the 351 it will have more power hands down. I wouldnt worry about roller and non roller blocks its just a benefit no major perfromance gain. I'd say the X heads will probably make better overall power on the 351. but the gt40's would be fine its not like your going to see much of a differance in power unless you plan on running 5000+ RPM.
 

bax

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Aug 22, 2005
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go with the 351 but make it into a roller. Use the cast iron gt40 heads
 

00gyrhed

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Aug 3, 2006
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cubic inches or cubic dollars.

I think you already new the answer. I doubt you will notice the difference in the CI and AL heads off road and on the street unless you like to wind it out and make noise. So if you want cheap go cheap if you want to spend some money on better heads go for it, (it does have a cool factor to it) but I would put a roller cam in the 351 and a really aggessive high lift short duration cam in it for about the same as building up the alumnium heads. Be better offroad and still have a nice smooth idle.

But I bet you would still be plenty happy with the CI heads and windsor as its sits.

If my 351 roller block had not needed a lot of machine work I would have run it like it sat and probably been very happy with it with nothing more than a good loww RPM torque cam.

Ended up with a 393 and new aluminum heads. Hope it makes me smile a lot I am pretty sure its going to be more engine than I even wanted when I started.
 
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KyleQ

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Apr 24, 2008
Messages
5,480
Go with that 351W and put the aluminum heads together - look at my old for sale thread for a set of those heads I sold. I gave all the specs for what parts Ford used to put the valvetrain kit together. You can still get it all, just not in an easy kit form.
 

rguest3

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Dec 13, 2012
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3,780
I have a 351w with the GT40X heads installed. The heads are made to match the Ford GT40 intakes ONLY and the Lightning set-up will work perfect and look great.

351W...

I pretty much asked the same question last week. I chose the 351W. You will have to stroke the 5.0 to get good torque which will be more expensive in the end.
 

70_Steve

Old Guy
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Dec 13, 2002
Messages
8,317
X(Oh crap, I lost count) 351 without question. For a street motor, or off-road, you can't beat the torque.
 
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greatguy57078

greatguy57078

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The GT40X heads are brand new in the box. I was told by a few others that the "valve kit" they used to sell was around $300 for everything.
 

br0nc0xrapt0r

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Did you really think you were going to go on here and have somebody tell you to get the smaller motor? ;D

The 351 might actually get better milage since it has to work much less to haul you around.
 
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greatguy57078

greatguy57078

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Actually I was looking for pros/cons. I had the chance to drive a 351w Bronco, and did not as I was not looking to buy another one. The truck was a clean and beautiful '75 Sport that actually sold for $5000.

I now have the opportunity to set this engine up at the end of my Bronco Connection restoration. It is hard to pull the trigger but the price is attractive and I do think this is the best choice.
 
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greatguy57078

greatguy57078

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Well here are a few goodies. I figure I will finish the heads out and replace the upper intake plaque seeings how this will now be 5.8 :cool:
 

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greatguy57078

greatguy57078

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Ok so I have a '69-70 351w rebuilt short block which I have heard has a little shorter deck than the newer roller motors. This rebiult block has TRW pistons, CompCam RV cam, Eagle I beam rods, ARP fasteners on the crank,rods and mains. I also have a GT40 upper intake and a GT40 Lightning lower intake which has the ports matched to brand new GT40X aluminum heads.

My next question would be....any guess as to how much HP this engine would be putting out? I am just curious as I know that is will be more than enough. Any ideas as to how much horsepower this setup would give me?
 
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