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Discussion Starter #1 (Edited by Moderator)
Let's face it, these days building a gas-chugging carbureted steet engine is about as fashionable as driving a Hummer. Conservatism is in, doing less with more is the new status symbol. In many ways driving a 60's Ford muscle car speaks to this new mantra - forgo a savings sapping monthly new car payment for a cheap project car. Use your DIY skills to get the car to daily-driver reliability. FM's Chris Monahan did just this, freeing himself of German sedan debt and taking on a much lower cost of ownership via a "pre-owned" 1965 Mustang coupe.



The craigslist find was a mere several grand and came with the usual understandings of work that may need to be done. A pesky engine tick we hoped was an exhaust leak turned out to be a cracked piston skirt, and so there came the impetus for an engine rebuild.

The Results First
Let's get right into it. If you want to know how to build a 331, be sure to see Build a 302 Stroker.) A few years ago we wouldn't have thought twice about a 347 stroker packed with a big cam, single plane intake, and wide mouth carb. We'd have taken credit for 500 horsepower and put up with the 10mpg debit. But in this economy no one is too happy to watch their cash dissolve into gallon after gallon of premium unleaded. On the other hand, how can any real gear head get excited about a weak sauce 289 rebuild? There has to be middle ground - decent mileage and better-than-good horsepower. We think we found it a well planned 331 build that churned out 461 flywheel horsepower, 400+ torque and is managing 17-18mpg with a T5 overdrive transmission.





The Ingredients
Our recipe isn't that complicated. We went with 331 cubic inches rather than a 347 simply to conserve - the 16 extra cubes would surely have equated to at least that many more horsepower, but on the other hand it would have hurt fuel economy. At a bit over 10.0 compression we can sneak by on 87 octane for daily duties or drop in 90 if we want to hammer it on the weekends. We selected a mild hydraulic roller cam straight out of Comps catalog, along with good quality lifters and rockers. We decided to use a dual-plane Edelbrock RPM intake and 800cfm Edelbrock carburetor, wise choices for conserving fuel and having a reliable daily commuter.



The secret sauce in this recipe was to use AFR's new comp 185cc heads. The heads feature smaller (8mm) diameter valves, correspondingly smaller springs and lightweight titanium retainers. The net result is a superlight valvetrain that allows for a much higher rpm limit. Contrary to popular belief an engines rpm potential is not due to the cam specs but usually the valvetrain weight (assuming the heads and intake are not the choke point.) The heavier the valve, the stronger the spring needs to be in order to control valve movement. It's a viscous cycle since stronger springs require thicker and more coils - further adding to the valvetrain weight. By lightening the valve, the valve train components can be smaller and equally lighter and the engine can rev even higher without incurring valve float. There is also a reduction in parasitic loss as heavier valve trains generate greater friction and require more engine power to move. These are well known engine building tactics at the competition level, but only recently have then been offered in a bolt-on production head. AFR offers the competition package in their 165cc and 185cc SBF heads.



The Competition treatment on the AFR 185cc heads also entails improving the intake and exhaust flow. The heads flow 290cfm through the intake and 225cfm out the exhaust between .550"-.600" lift. These heads are capable of supporting 600 horsepower and while many will point out that we are really not utilizing all these heads have to offer, for the extra $300 (approximately $1800 versus $1500 per pair) we not only gained significant power over the standard heads, but set ourselves up nicely for any future engine upgrades. (A couple years back we compared AFR 165 standard and Comp heads on a 347 build, and found the Comp package to be worth and additional 15 horsepower' see Dyno Duel.)



Conclusion
By no means was this a "budget" buildup. We were willing invest a decent amount of money into an engine that would be fun, reliable, and streetable. All said and done we tallied up around $5000 in parts and labor to build a small block Ford with 460 horsepower and a neck breaking 400+ torque across the rpm range. Combined with a T5 overdrive transmission we're seeing 18mpg in mixed city and highway driving, and that is with just under 500 miles.


Sources:

Joe Sherman Engines

Air Flow Research

Scat Enterprises

Competition Cams

Probe Industries

Performance Distributors

Fidanza Flywheels and Clutches
 

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Outstanding info along with the specs. Question, any pitfalls to avoid that you ran across? Or anything you'd have done differently after finishing it? Thanks
 

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Outstanding info along with the specs. Question, any pitfalls to avoid that you ran across? Or anything you'd have done differently after finishing it? Thanks
I can't think of any pitfalls. I was really surprised that this camshaft made as much power as it did, considering it is not that big. It really shows that these AFR heads are amazing. The only thing that I would say is don't forget to get the rotating assembly balanced. Scat performed this work for us. Don't attempt to put an unbalanced assembly together, you will just vibrate the engine to death. There was one mistake I made. I was in such a hurry to put the motor back in the car that I forgot the dowel pins on the flywheel. I had to rip it back out to take care of it. I read numerous posts on Fordmuscle about vibrations, so this is something I wanted to take care of. This engine, transmission and drive shaft have NO vibrations what so ever at any RPM. It is truly a pleasure to drive.

Joe Sherman built the motor, and he strongly suggested getting the engine dyno tested. While it is expensive to do so, it is a great investment because you know that when you plop the engine in the car it will run. No messing with timing or broken parts.
 

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Here is a dyno video:

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I had Stefko Racing build this motor for me, but we did use Callies rotating assembly (347) & Edelbrock RPM heads that did require so much work that i should have waited & bought the AFR heads, live & learn, eh
The end result is a killer motor though
484/454 in a 2900pound car, its a little beast
thank you
 

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Hey 67 Stang,
What kind of mileage did your 331 cid, Mass-Flo injected engine get? Seems to me, sans blower, your 67 Mustang featured in the DIY EFI article should have gotten at least 22mpg.
 

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Hey 67 Stang,
What kind of mileage did your 331 cid, Mass-Flo injected engine get? Seems to me, sans blower, your 67 Mustang featured in the DIY EFI article should have gotten at least 22mpg.

You would think, but it never broke 15mpg. It had/has a big solid roller cam.
 

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What did you do to the t-5 to make it handle the extra power? Is it a stock tranny because from what I've heard, stock t-5's don't really like staying in one piece with that kind of power.
 

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What did you do to the t-5 to make it handle the extra power? Is it a stock tranny because from what I've heard, stock t-5's don't really like staying in one piece with that kind of power.
It is actually a T5z which is rated for 330ft/lbs of torque. I think it will last for a long time because this is a daily driver and the car will probably never have slicks. That said, 67stang, the owner of project 67 has a stock T5 rated for 300ft/lbs. He has over 200 drag strip passes on it and its never been rebuilt. I think it really depends on vehicle weight and how hard you shift.
 

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I'm interested what rear end is in the car (8" vs. 9") and what gears are being used to get the mpgs. Also, I have a similar setup going into my '66 - how is the low end power like for daily driving with that cam and what rpm does it like to idle at? Thanks.
 

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I'm interested what rear end is in the car (8" vs. 9") and what gears are being used to get the mpgs. Also, I have a similar setup going into my '66 - how is the low end power like for daily driving with that cam and what rpm does it like to idle at? Thanks.
The car has a limited slip 9" with 3.25 gears. Essentially at 65mph, the gas pedal is barely pressed down, about a quarter inch. The car idles at around 800/900 rpms and has plenty of low end torque. The T5z has a 2.95 first gear, that coupled with an aluminum flywheel - you do have to give it a tiny bit of gas to get going. I remember in a 66 mustang of mine with a 351w and 3.80 gears (also a T5) you could start off from idle without giving it gas. If I had to do this combo over again, I may have picked a steel flywheel or a 3.55 gear ratio. None the less, the car has plenty of power (even with it's gearing) to do nasty burnouts ;)
 

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I thought Joe Sherman said why waste money on a 331 when a 347 will make more power, cost about the same and does not have oiling issues or side loading problems. I have a 331 and am very happy with it. I don't think you need a 347 to make a lot of power. A 331 will make big power with the right parts. And if I had it to do all over again, I would still build a 331 over a 347 just because everyone and their brother is putting together a 347.
 

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I thought Joe Sherman said why waste money on a 331 when a 347 will make more power, cost about the same and does not have oiling issues or side loading problems. I have a 331 and am very happy with it. I don't think you need a 347 to make a lot of power. A 331 will make big power with the right parts. And if I had it to do all over again, I would still build a 331 over a 347 just because everyone and their brother is putting together a 347.
For me it was a gut feeling. I had read the countless debates about the 347 and decided to not even be involved in the possible problems and take a proven route. My goal is to make this motor last an easy 100,000 miles. I don't see why not, this is a daily driver with very few WOT runs. I've had faster cars, and honestly I have come to the conclusion that power isn't everything. Having a car that is mild tempered, fun to take sharp corners with and not have to worry about rebuilding every season is what I'm after.
 

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Nice build. Should be a lot of fun in that car as a driver. Curious why to stopped the pull early? Is that the highest you pulled it? Can you post up the actual dyno sheet?
 

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Nice build. Should be a lot of fun in that car as a driver. Curious why to stopped the pull early? Is that the highest you pulled it? Can you post up the actual dyno sheet?
That is where power started to drop, due to the dual plane intake. We don't have an actual dyno sheet, we just have a printout of the RPMs and the power/torque. We used that to create the graph in the article.
 
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