302 or 351w

[Z-EATER]

I'm getting ready to build a fox body car that I want to street race in but still be able to daily drive it. I just can't decide if I should go 302 or 351w. If I go 302 I'm thinking of a 347 and if I go 351 I'm thinking of a 393. Either way I'm going to s/c it. I'm also looking for a min. of 500 rwhp and torque without the s/c. I like the 351 because of the ci avalibilty, but I've heard that the 302 block is stronger. I'm also thinking about down stroking a 351w, but I don't know much about down stroking a motor. What are the advantages of down stroking and is it a good idea for a 1/4 mile car with a six speed trani? Of my 3 options which would be the best if I end up running a nos system (which is a very slim chance)?

[SpectorV]

I would go with a 351. It is stronger and will make more power, or the same power with less stress.

[DarkShadow]

A Ford production 302 likes to split right up the middle in the neighborhood of 500hp...

[bullitt482]

Hmm.... Displacement is all but directly proportional to horsepower and torque. Why 393 when you can go 408 through Coast High Performance

[rocknbronco]

Why go 408 when you can go 427

[JROC]

Why make Billions, when we can make Millions?

[Matthew]

Quote: Originally Posted by bullitt482 Hmm.... Displacement is all but directly proportional to horsepower and torque. Why 393 when you can go 408 through Coast High Performance

That's only sort of true. Power is really a function of the bore - bigger bore motors have more power potential. Longer stroke motors make more torque at low RPM's, but have a reduction in RPM potential proportionate to the increase in stroke, so their power potential does not really increase in proportion to the displacement increase. This is one of the reasons why the more racey motors use a big bore and a modest stroke - that's the way to get more power.

As far as an "at least 500 rwhp" motor before supercharging is concerned, it is possible, but a pretty tall order, even if your benchmark is using dynojet numbers. A production 302 block is not going to be a worthwhile platform for that kind of setup, and if you are really talking about building an 800 RWHP motor once the supercharger is on, you should forget about any production block and start thinking about a $50000 budget by the time you have sorted out clutch or torque converter, transmission, rear end, cage, exhaust, and all the other parts that will be required to make a complete vehicle capable of handling that power. Maybe that's the kind of ride you are talking about, but if you are on a $10000 budget, you need to adjust your expectations a little.

-Matthew

[bullitt482]

Quote: Originally Posted by Matthew That's only sort of true. Power is really a function of the bore - bigger bore motors have more power potential. Longer stroke motors make more torque at low RPM's, but have a reduction in RPM potential proportionate to the increase in stroke, so their power potential does not really increase in proportion to the displacement increase. This is one of the reasons why the more racey motors use a big bore and a modest stroke - that's the way to get more power. -Matthew

Let me guess, your one of those 331's are better than 347 guys.

The only "problem" that there is to deal with on a longer stronger would be to compensate for the rotating mass with lighter rods and pistons, which is already solved with 99.9 percent of engine bore kits out there

50,000 for 800 whp?? Yeah, if you pay someone to do EVERYTHING.

I say 408 with a hellion turbo kit we'll say 18,000 right there to way over shoot. 5 thousand (another overshoot) for your choice of tranny/tq converter/clutch setup, 3 grand for Ford 9 inch fully prepped, 2 grand for fuel(full returnstyle setup), 2 grand for ignition, and we'll just round it up and say 5 grand for a bigstuff 3 and tuning. And that's WAY overshooting. You're 15 grand off.

[Matthew]

Quote: Originally Posted by bullitt482 Let me guess, your one of those 331's are better than 347 guys.

Both those setups use the same bore. I'm a 4.185" small block bore guy myself. Let me guess, you are a 6000 RPM is the limit for pushrod Fords kind of guy.

Quote: Originally Posted by bullitt482 I say 408 with a hellion turbo kit we'll say 18,000 right there to way over shoot.

Good luck keeping that together. This is the kind of setup I am talking about: BENNETT RACING ONLINE • 800-240-RACE • #1 ENGINE BUILDER

Quote: Originally Posted by bullitt482 5 thousand (another overshoot) for your choice of tranny/tq converter/clutch setup, 3 grand for Ford 9 inch fully prepped, 2 grand for fuel(full returnstyle setup), 2 grand for ignition, and we'll just round it up and say 5 grand for a bigstuff 3 and tuning.

All in the ball park - A little high on the ignition system maybe.

Now add 10 pt cage - at least $2000 installed, more like $5000 if its chromoly, a full exhaust - $1000 for headers, $1000 for the rest in large tubing mandel bent, seats and harness -$1000 if you want two seats and something nice, K-member and full suspension - $2000 or so, and then do ALL the work yourself.

Quote: Originally Posted by bullitt482 You're 15 grand off.

That all adds up to $54000. With no labor except the long block assembly. Oh, and that didn't even get a water pump, alternator, or accessory brackets, and probably a dozen other little details.

When you are talking about 800 HP AT THE WHEELS, even on a generous dynojet, you are talking about some exotic stuff. If you are only talking about 800 HP on an engine dyno its still going to be tough with the kind of parts you are talking about. I do enjoy coming up against guys with your mindset at the track though, because after a couple of rounds of qualifying you are scattered all over the place and no longer a competitor to me.

-Matthew

[bbunt302]

351 all the way. If you can afford it, do it. More torque, stronger block and more possibilities.

[SilentNoise]

Quote: Originally Posted by bullitt482 Let me guess, your one of those 331's are better than 347 guys.

It all comes down to what you want out of your vehicle, but his 1990 coupe has an NA 399ci (351W-based) that's running mid-low 10 second quarter miles at an altitude of 2200'....... so call me crazy, but he might just have a tad bit of experience in this kind of thing

[DarkShadow]

Quote: Originally Posted by SilentNoise It all comes down to what you want out of your vehicle, but his 1990 coupe has an NA 399ci (351W-based) that's running mid-low 10 second quarter miles at an altitude of 2200'....... so call me crazy, but he might just have a tad bit of experience in this kind of thing

[bullitt482]

I was overshooting it..... Why is just when people have something fast they automaticallly know more than other people? I've never understood that... Maybe it's the wow factor?




That was assuming you buy everything new which is crazy. Please, a 408 would be fine for that application.

How does 35,000 + 7,000 equal 54,000? Even with a chromoly cage that you priced it is more like 45,000 dollars....


Like I said, that's assuming you pay someone to do all that stuff yourself. Hell 400 bucks for an electric water pump, replace the shaft on the stock oil pump, and that's still no where near 50,000.

Look, I'm not trying to make an enemy out of you in the least, especially since you are a new guy and a fellow pushrod guy, I just don't think it would cost near that much, unless you have to pay someone to do it all. I like these discussions, I like to be forced into research to learn more. And no, I'm not one of those guys who thinks pushrods shouldn't be revved to over 6,000 rpm. Now if it was still a hydraulic roller with big duration and/or lift then yeah, but that involves having the right tool for the job.

[bullitt482]

To add to that post, you sound more like the person who races every weekend and actually competes which that would be way more likely to fit your application(the bennett racing engine you linked), but for me, I like to go fast occasionally and be able to drive it every day(not saying you can't use that motor everyday), so me, personally, would not need something that extreme.

[Matthew]

The real issue here is that Z-Eater says he wants 500 RWHP without the supercharger, then he wants to supercharge it. It is extremely unusual to even make a 400 RWHP pass on a Mustang dyno, which is still only around 450 on a dynojet using a production style block and jobber hardware. A CHP 408 with AFR 205's, Victor 5.8 EFI intake, 1.75" - 3" long tubes and exhaust and a Comp 292R solid roller (about 260* at 50 thou and .627" lift) made 385 at the wheels on my MD-600 dynamometer. As I said in my original post, either Z-Eater needs to have a big budget for his project, or he needs to adjust his expectations. That's all there is to it.

As to the math, adding $30000 for a typical motor in that class like the Bennett Racing motor I linked, and $24000 for all the extra parts, adds up to $54000. I will say that Jon Bennett's motors are worth every penny. Since I got one of his short blocks and a set of heads from Total Engine Airflow and put it all together I have been in four events and won 3 outright and went out of the final one with an electrical problem.

In the dyno business I see guys every day with huge power dreams and no idea of what it really takes to make it. A $15000-$20000 budget will build a hell of a car, but actually getting to the plateau that Z-Eater is talking about costs a ton of money and a ton of work.

One problem out there is the fact that a lot of engine builders advertise their engine output in gross horsepower from an engine dyno. This number is always inflated substantially with respect to what the engine will make at the rear wheels. This can create some wild expectations which are quickly dashed when the final setup is brought to the dyno or race track. I'm just trying to open Z-Eater's eyes here so that he ends up with a budget and expectations that line up with each other.

-Matthew

[bullitt482]

Quote: Originally Posted by Matthew One problem out there is the fact that a lot of engine builders advertise their engine output in gross horsepower from an engine dyno. This number is always inflated substantially with respect to what the engine will make at the rear wheels. This can create some wild expectations which are quickly dashed when the final setup is brought to the dyno or race track. I'm just trying to open Z-Eater's eyes here so that he ends up with a budget and expectations that line up with each other. -Matthew

Gotcha...... The thing is with dyno numbers is that you(figuratively) can say I want to get XXX hp at the wheels, when in reality the person should be asking what kind of times they want to run. With your experience of all people, dyno numbers aren't too important unless you compare it to a baseline on the same dyno and are trying to improve on said power. Ok.... wait, I think I just lost myself and was about to start a totally different rant that has nothing to do with the thread, so I'll stop while I'm ahead, errr... behind or whatever

WOW, you live all the way up in Canada and you deal with bennett over in Alabama. I've ALWAYS heard awesome stuff from his shop and he is the only shop that would ever assemble anything I own, but damn, I had no idea he was so big... I mean, I knew he was big in NMRA/NMCA and so on, but all the way up north?

[Matthew]

Quote: Originally Posted by bullitt482 WOW, you live all the way up in Canada and you deal with bennett over in Alabama. I've ALWAYS heard awesome stuff from his shop and he is the only shop that would ever assemble anything I own, but damn, I had no idea he was so big... I mean, I knew he was big in NMRA/NMCA and so on, but all the way up north?

I had a locally built 351W based (production block) motor, and it worked pretty well, but it always had lots of blow-by and we were getting tired of having to face power adder cars in shootouts all the time and losing. When my engineer and I started looking for a naturally aspirated combination in a street car that could stand up to the supercharger and nitrous guys, it became pretty clear that there was a very very short list of guys who could setup a short block that was going to work, and Jon Bennett was at the top of that list. We got him to do the short block and oiling system, and I put together the rest of it with some heads from Total Engine Airflow, and now we are running 10.50's at 2400 ft tracks on straight 91 octane pump gas with under 400 inches in displacement, and a full DOT legal, full street weight car with a 5 speed H-pattern (TKO-600) transmission. That's enough to beat most of the supercharger and nitrous guys, and it's a nice reliable combination. Like I said earlier, Jon Bennett isn't cheap, but he's worth it every penny.

-Matthew

[rocknbronco]