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Discussion Starter · #1 ·
ok, obviously there is no replacement for displacement. I have a fresh built 331 stroker engine and a small blocked 40,000 miles 351(came out of a van). Both have the same roller cam, performer intake, holly 650 dbl pmper, and main girdle. I'm interested in road racing, opentracking the car. Can the 331 perform as well as the 351w? Those who have used both, other than displacement, what are not so obvious differences? By the way, the 351w is a roller, using the conversion tie bar lifters usinf a 5.0 H.O. type cam not the small base cam. Thanks everyone.
 

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Assuming a reliable build, go with the 331. It's lighter (50 lbs on the front end is meaningful..) and you won't miss the 20 cubic inches at all. Plus, and this is a big plus in a road race app - more header clearance and clearance to fiddle with front end alignment. You also mention the 351 has 40,000 miles - this is not a fresh engine, so the 20 c.i. advantage is largely non-existant.

Have fun !
 

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While I have neither, I'd go for the 331 because it's about 75 pounds lighter then the 351W. I think the 75 pound difference over the front wheels will have a bigger effect in road racing then the addtional 20 cubes.
 

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Since you already have the 331, I'd go that route. If you were LOOKING to build a 331 OR 351W, I'd go 351W since there's more potential. :D

I'm into autoX and chose to go with a 351W stroker ( 408ci ) so that I can put it in 2nd and let the torque do the rest. With the 12.5:1 289 I was running, all my power was above 5000rpm, so I had to keep it in 1st and just hit the limiter.

I also had a bit of UNDERsteer where the tires wouldn't go where I pointed them. With the extra weight up front, I should have a little OVERsteer, which is more desirable for my driving style. :D

In yer situation, I'd definately go FRESH 331!
 

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In steady-state cornering (skid-pad), adding weight to the front will INCREASE understeer, which is something our Mustangs don't need any more of for the most part.

Sure, you can still snap to very flashy and noisy power-oversteer, but that extra 75# on the front tires isn't going to improve your auto-x times; it's much more likely to hurt them.

---Jim
 

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In steady-state cornering (skid-pad), adding weight to the front will INCREASE understeer, which is something our Mustangs don't need any more of for the most part.

Sure, you can still snap to very flashy and noisy power-oversteer, but that extra 75# on the front tires isn't going to improve your auto-x times; it's much more likely to hurt them.

---Jim
Wow - that's counter-intuitive! I assumed more weight meant more traction, less weight meant less traction. Given you don't OVER extend the grip of the tires. I realize that weight going one direction wants to continue that direction, but lack of weight can cause the same problem with lack of grip.

Guess I need to read more of my "How to Make Your Car Handle" book. ;) That, and go out and run through a few cones to see the difference. :D
 

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Discussion Starter · #7 ·
No autocrossing for me, I hate the cones. Roadrace and opentrack and daily driving. I actually have both engines. I'm running stiffer front springs so that will help with the front handling. I'm trying to find a nice balance of high raw power and nice handling. I'm thinking of putting the 331 in storage and building the roller 351w. Just wondered what experienced, experienced, experienced 331 and 351w users felt about the comparable performance of the engines. Thanks for the replies.
 
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