Trick Flow 170cc heads too small for a 393?

I will be building a 351 Windsor to swap into my 1980 F350 SRW truck to replace the worn out/leaky/gutless motor that is currently in it.

I think I've decided to go with one of the 393 stroker kits.

I was wondering if the Trick Flow 11R 170cc heads would be a good fit for my application.
I'm shooting for around 400-425 HP and as much torque as it can deliver.

Unfortunately gas mileage is a factor, as I have no need or want for a second vehicle right now.

If I aim for a 5000-5500 RPM redline, would these heads get me to my goals? Or should I go with the 190cc version? FWIW it will have headers, a Performer RPM intake manifold, (probably) custom ground roller cam, upgraded ignition, etc.

The 11R flow numbers appear impressive for 170cc intake runners:
https://static.trickflow.com/global/images/chartsguides/t/tfs-52516301-c00.pdf

If I could eek out 15-ish MPG highway with a 5 speed manual transmission I'd be happy.

Thanks for any input!

If you are going for low-end torque and not high-end horsepower then the smaller passages are what you want.  The small passages are good for torque but hurt horsepower.  To me that's what you want in a truck.

The 170's have 53cc chambers while the 190's come in 56 or 66cc versions, right?
While (IMO) aluminum heads are good for at least another point of compression, a lot of how they will ultimately perform depends on your cam.

Which gearbox do you intend to use?
The later Zf's could handle 450 lb/ft but they shift like a truck.
The M5OD likely won't (for long)
I think a stock 9" will probably take it better than a stock 8.8.

A stock DSII ignition is rock solid at 6,000 rpm so there's really no need to waste money there.

No mention of how you intend to fuel it...
Big carbs aren't great at economy. And a Performer RPM doesn't support spreadbore's.

I know that 400+ horsepower has its appeal -and newer trucks can do it- but Windsors go back 60 years. They are ubiquitous and there is plenty of performance support still available for an engine family that was gone 25 years ago.

Consider your horsepower goals.
I'm going to tell you that a Bullnose will be a handful with factory suspension and street tires.
350 honest rw horsepower is still more than twice it made and leaves you a lot more room for economy and smooth response.

Sorry if I sound like a killjoy. It's not my intent to discourage you, and I'm sure you're going to do what you like anyhow.

I may go all out with one of those newer Tremec TKX transmissions.

And yes it will stay carbed, I figured 650 CFM would be a good fit. As for the spread-bore carbs, don't they make adapters that bolt on?

I currently do have the DSII ignition in there, no complaints.

I'm not out for a race truck or anything hah, but I've always wanted a truck that could do truck stuff but still have some HP behind it, if you get what I mean. I certainly don't want to overdo it and be unhappy once the new factor wears off.

To clarify I did mean 400+ HP at the flywheel.

I guess what I need is good torque for a truck, that doesn't run out of steam at 4,000 RPM.

I'm old enough that I'm not familiar with the TKX but I have put a TKO 600 RR behind a 347.
Bill's Cobra was making 440 hp 450 tq.
I think the Tremec's shift great and can easily handle that kind of power but I don't know what the ratios are like.

The RPM isn't as tall as an air gap but depending on what you chose to use for an air cleaner you may have to check hood clearance.  (I will say I'm used to my 460 and don't know exactly how high a 351 would sit with that intake)
I do have a 650 AVS sitting in a bag on the shelf.  😉

As Gary pointed out if you are looking for torque to do "truck stuff" you need to have runners tight enough to keep the port velocity high at low RPM.
The 400 he has in his Dad's Truck is much closer in displacement to your build than my 460 ever was.
It won't ever see a trailer or a ton of stuff in the bed

There's a thread on here about that and Tim used aluminum TFS heads.
It is a 335 series though, so definitely not apples to apples.
But It is impressive!    Even epic....

I rarely get north of 10mpg and I'm definitely not making 400 horsepower.  
Big blocks are a different beast.  

It sounds like you have some awesome plans!  👍
Hopefully you will start a build thread so we can all follow along.

Yeah the TKX just came out a couple of years ago, if that. It's supposed to be an updated, smoother shifting and slightly more compact version of the TKO 600. Can't find any bad things about it so far, other than the price hah. They offer a number of gear ratios that I'm sure I can work with.

I figure the intake air velocity would be great with either the 170cc or the 190cc versions of the 11Rs, but I read something about port cross-sectional area being important as well as the flow numbers. Maybe it won't matter much with my applications.

I have more than enough room under the hood so clearance shouldn't be an issue.

I may indeed start a build thread, but my progress will be slow-ish on account of my bank account is a cruel joke a lot of the time.

Whose stroker kit are you going to go with?
I'm sure the pistons will help determine what chamber size you want.

Sectional area determines the mass of air's inertia you have to get moving (and stop) each time the intake valve opens.
At sea level you have 14.7 psi pushing.
And at 5,500 rpm you have to do that 46 times a second.

I follow a porter on YouTube (Charles Servedio) who is working on a pair of GT40 heads for a 351W based combo right now.
It's interesting to watch someone who has been doing it for ~45 years when they explain what we are seeing and why things do (or don't) matter

I'm not quite sure which kit I'll end up going with. If I get the Trick Flow heads I may try to make use of the pistons that Trick Flow makes/sells for their heads so I don't have to worry about fly cutting and/or clearance issues.

I'd think the highest compression I could get away with using aluminum heads in sweltering SE Texas, with 87 octane, may be around 9:1, not totally sure though.

I think that you're looking at 10:1 minimum, but I'm not the one building it.
I definitely can't see dropping that kind of coin on aluminum heads and not using it.

Or, you could save some build budget and just spend it on better fuel for the next decade

SubSonic wrote

I'm not quite sure which kit I'll end up going with. If I get the Trick Flow heads I may try to make use of the pistons that Trick Flow makes/sells for their heads so I don't have to worry about fly cutting and/or clearance issues.

I'd think the highest compression I could get away with using aluminum heads in sweltering SE Texas, with 87 octane, may be around 9:1, not totally sure though.

I have been looking at 351W based stroker kits as well. Like you, I would like to build a motor than can run on 87 octane. The problem with all that I have found is that, if you buy the entire rotating mass (crank, rods, pistons), the kits all land around 10:1.

If you want to go shopping for pistons separately, you will pay more in the end, and you have to juggle a lot of math to make sure the pin height and quench height both come in where you want. Not to mention concerns about getting other dimensions and parts right - pin size, getting the right ring package, how much was shaved from the deck when the block was machined (many machine shops don't seem to keep track of that for you, or supply you with a final deck height number). Unless you are an experienced engine builder, some of that stuff can be pretty daunting.

Another hurdle is, if you are buying aluminum heads, the less expensive ones tend to have the smaller chamber sizes (58-62cc). You have to shell out about twice as much to get into the ones that have the 70-ish cc chamber sizes, and guess what, they're mostly on backorder status.

I'd be interested to see what you can come up with that allows a 9:1 compression ratio and still has good quench and rod ratio.

I'm almost at the point where I'm willing to buy off on running 93 octane. I work from home, have other cars to drive, and probably only put about 3000 miles a year on the truck, if that. At 12mpg and about an 80 cent upcharge for the premium gas, I'm only going to spend about 200 more per year on gas. Contrast that with spending more than a thousand for larger chamber heads, and it does not seem all that significant.

On the upside of that though, higher compression yields higher torque, which is what I want in my truck.

If you have aluminum heads there's no reason to limit yourself to 9:1.

Where do you live that premium is that much more expensive?
Around here (southern CT) 91 R+M/2 is $.10-.15 over 89.
Some stations still have 93, but it's not a popular option.

is CT. really big enough to have a northern / southern?

I'm in the "toe"...  

There's definitely a huge difference between being 25 mi from Manhattan and the rolling farmland in the Litchfield hills.

ArdWrknTrk wrote

Where do you live that premium is that much more expensive?
Around here (southern CT) 91 R+M/2 is $.10-.15 over 89.
Some stations still have 93, but it's not a popular option.

I'm in north Texas, just north of Dallas. The prices today at the local RaceTrac (high volume gas stations down here) are:

Regular (87): $3.60
Midgrade (89): $3.85
Premium (93): $4.15

At least, that's what's posted on their website, I'm not certain those numbers are up to date, I seem to recall more like $4.59 for premium last time we filled up the wife's car. Regardless, I guess the span is only about $0.55, if those prices are accurate. Which makes an even better argument for going with a higher CR.

Of course, if gas prices go up, which I think is a fairly safe bet for the next couple years at least, that span might also go up.  

Is 9:1 about the highest I can go with 87?

I do not have other cars to drive, nor do I want any. Honestly I don't like cars at all, and the new/used truck prices are crazy. Plus newer vehicles have no character. I realize most people buy older vehicles as projects/toys and have other vehicles with good mileage and whatnot. I'm not really interested in most modern cars.

What I'm saying is, I'd really prefer not to have to fill up with 93. I could probably be convinced to go with 89 hah. Around here that's the mid-grade. The $.50 a gallon will add up.

I figured 9:1 would be about the safe maximum in a hot/humid climate.

Besides a few horses/torque, what else would I be losing?

These guys have some 170cc 11R heads with an option for 53cc or 63cc combustion chamber sizes:

http://fordstrokers.com/induction/trick-flow-cylinder-heads/trick-flow-twisted-wedge-170-track-heat-11R

Filled up at Forbes with 93 this evening @ 3.99 9/10   (shrug)

Not sure why gas is more expensive in Texas.
We don't have any wells or refineries here.

Like Pete said above there's a whole lot of calculus to be done when juggling chamber volume, pistons, deck height, quench, rod ratio, cam overlap and timing, (which affects dynamic compression) port velocity and volume, etc...

Maybe he has better advice to offer since he has been looking at the same metrics as you?

Simulations are getting better and better.
Have you plugged all these numbers (plus gear ratios, truck weight, tire size etc...) into Desktop Dyno or something like that?

My brain just has a hard time putting 15mpg, 87 octane together with 400+ horsepower & Tq @ 5,500 rpm,  and a 351 in a 1980's pickup.  

I think runner volume is the least of your issues and would definitely be comparing cross section with that of your Performer RPM intake and whichever valve size you go with
.

SubSonic wrote

Is 9:1 about the highest I can go with 87?

As a very very general rule, that would be about right. But there are so many different factors that go into it, it's impossible to say. I think the later EEC trucks had a knock sensor in one of the freeze plugs, so if you went with a system like that, you could push it a bit as you will have a safety net built in.

Other things off the top of my head that affect how much static CR you can have (I'm sure this list has many items missing):

- Valve overlap
- Rod ratio
- Ignition timing
- Altitude
- Temperature
- Chamber design
- Quench height
- Vehicle weight and towing requirements

Heck even things like spark plug heat range and ring sealing can have a minor effect.

I have to agree with ArdWrknTrk, your stated goals may be a bit optimistic. Realistically for a 351w, I think you could shoot for and achieve 350hp and 12-13mpg on 87 octane in a lighter SWB bullnose truck.

SubSonic wrote

These guys have some 170cc 11R heads with an option for 53cc or 63cc combustion chamber sizes:

http://fordstrokers.com/induction/trick-flow-cylinder-heads/trick-flow-twisted-wedge-170-track-heat-11R

Is that $1540 price tag for 1 or 2 heads?

In my playing with CR calculators, 63cc heads don't get you down to 9:1 in any of the stroker packages I looked at. You could do it, as there are may thicknesses of head gaskets available, but then you will be sacrificing quench, which basically equates to hp/torque.