hello everyone. im brand new to this forum, and have done some searching. i have an 84 250, 351w, 4 speed. im in college, and looking to add some torque to my truck next summer when ill be working full time again. im not sure what casting my heads are. which heads would be best for TORQUE. im not concerned really about hp. i heard it would be best to stick to iron heads, which ones would be best for low end torque. (e7's, gt40, gt40p?) are the aftermarket heads that would produce more low end torque? maybe AM iron heads? wat about afr 165s? these are aluminum but i was thing with smaller ports maybe it would produce more torque? oh yeah ill be using a custom cam, depeding on what heads are chosen. looking to also use 1.7 rockers. any input is greatly appreciated. thanks

 

The 165 heads will give you good torque. I am interested in your cam profile and intake/carb setup. Usually the whole air-fuel system needs to be examined. Can we get an idea of where in the power band you want this torque? I noticed as you build on stock strokes, your power is higher.

You might not need heads depending on your goals. Can you give us an estimate on how much torque you want?

 

Ptf - Welcome to the forum. I'd like to help you but I'm having trouble reading your post. Sorry, but I'm old school and don't struggle with posts that aren't easy for me to read, and yours isn't due to it not being easy to see the sentences w/o caps at the front.

Having said that, I think you are asking what heads to go with. And, since I've played with that aspect a bit let me take a stab at it. Basically, all of the heads from the 70's up until the 90's are "smog heads" and are awful on the exhaust side. You can make that better by grinding out the bump, as I described in this thread.

But, I have to tell you that won't get you torque, as that comes from compression and stroke. The best way to get compression is via a head, like a GT40. However, there are several varieties of the GT40 and each has a different combustion chamber size. You are going to want to pick a combustion chamber size that fits with the pistons you are going to use and the deck height of the engine. And all of those pieces have to fit together. Here's a link to Summit's CR calculator, wherein you will have to enter things like deck clearance, dome volume, and even the thickness of the head gasket.

And then there's the stroke, which gives the mechanical advantage, aka leverage. So, if you really want torque go with more stroke along with a 9.5:1 compression ratio.

 

You are dealing with a retarded cam profile if it is stock. That all needs to be changed if you are seriously considering heads.

 

Go full roller on the top end and don't waste four time with a flat tappet cam. Technology of todays motor oil doesn't support flat tappet top ends.

 

RL250, its got the stock 2 barrel carb so im thinking going with a holley 4 barrel 650, maybe smaller.(not looking for hp) trying to keep the rpm range low (0-5000ish for hp) and 1 or 2000-2500 for peak torque. in other words, low rpm torque. for intake, thinkin just a edelbrock non emissions rpm intake (0-5500 rpm range) maybe just have my current heads rebuilt with some mild exhaust portwork and leave intake untouched? what are your thoughts?

 

Your '84 is starting pretty low in the power department unless it is an HO motor:

Engine_Specifications

This here says the 4bbl and cam were the differences:

https://www.ford-trucks.com/forums/1...d-351w-ho.html

The cam is all about cylinder filling, and in turn, cylinder pressure or "brake mean effective pressure" if you want eye-searing detail. (google it)

The higher the pressure, the more torque you get. Thus, higher compression will give you more torque, as will cylinders that fill easier.

Adding the 4bbl will give you a bit more power, and sound cooler, but the thing you will notice most is cost of doing it and the extra gas you will run through.

For real power, different heads with better ports and smaller chambers for higher compression, and a cam tailored to the compression ratio and other factors.

As for stroke, that gives you a bigger engine, and that gives you more torque at a lower RPM usually. But a stroker is a big budget undertaking, so try your 4bbl but keep the 2bbl and manifold.

Also, torque is measured, HP is calculated (can't recall who said that here). If you get one, you get the other, expressed in a different way. Modifications to an engine usually raise the rpm where you find peak power. Larger intakes and carbs can kill low end but give you nice top end. A smallish 4bbl will be ok.

 

85e150 makes very valid points. But to keep the rpm down, you'll get more torque out of a stroker kit. Heads and stroker kits run about the same for parts. Downside to the stroker is the extra cost in machine work.

To really get toque that low anywhere close to my estimates (have not dyno'd my setup yet), a stroker and small 4bbl is ideal. I like my street demon 625cfm for torque. It has small primaries and big secondaries on a square bore base. A 600-650 should feed a 351 fine.

I think the Weiand intakes are a bit better, but you can actually get a complete set from Edelbrock that includes heads, cam, intake, and carb. If you are on a budget, go for the Edelbrock package. The peak torque will be a bit higher than you want, but still reasonable. Down the road I will be building a Windsor to 427 and installing SPFI on it. My goals are 450 ft-lbs below 4000 rpm for a desert/Prerunner truck. I'll be following your work to help with my build.

 

I would sit down and do the math for parts and machine work to get what you want out of the motor. I am saying you will be spending close to $3k if not $4K. A nice crate motor can be bought for that and all you have to do is drop it in and tune it.


Just saying, if I ever decide on another performance motor it will be a crate. I am doing a budget build 351W now and just the machine work is $900. I will have $3K easy in my motor with a lot of the parts being left overs from other builds and next to free from friends.