What is the fascination with deep gears and compression? Another rant.

[Bob Holmes]

I don't understand the fascination with rpm. The only reason you need to spin an engine is if you have small displacement in a racing application and you aren't allowed to use forced induction. Or you just want to spend money and bullshit people.

Other than that, get the most power you can at the lowest rpm and gear it correctly. You'll spend less money, spend less time on maintenance and enjoy driving your vehicle for a longer period of time before rebuilds.

TC, RPM does not necessarily mean higher piston speeds. Which has a higher piston speed, a Nascar engine or a Formula 1 engine? We all know that Formula 1 engines are limited to 18,000 rpm. Nascar is gear limited to somewhere around 9,500 rpm +-a couple hundred rpm. Here is a great comparison article: http://www.epi-eng.com/piston_engine..._cup_to_f1.htm

What we do know is that we wouldn't want to run either one of those engines in a daily driver or even weekend street warrior vehicle. They aren't worth a damn until they are in their very narrow rpm power window. Maybe they'd be worth a kick at the parade grounds where you trailer them in and then start them up to gather the crowd.

Brian makes the point I always pound on, application is everything. There is no one correct way to build any engine. And T455 is also right on that applying techinques from a small block chevy to damn near everything else is sure to cause a less than proper build.

Its frustrating to see the herd mentality applied to every build.

[Orange65]

What works for one engine, doesn't work for all. However, keep in mind:

For any engine- more RPM means more air and fuel taken in per unit time and burned and more power produced. An engine converts chemical energy to mechanical energy. The more you put in, the more you get out.

However- it also depends on the heads and how well they can flow. An Olds head doesn't flow very good. And as for the 403 olds, it has a 3.35" stroke- pretty short and not great for torque but good for minimizing the piston speeds and stresses in the engine. But due to the heads, it runs out of steam pretty early in the RPM range.

I have always heard the best gear for a drag car is the one that gets the engine to the redline at the finish line.

[Thumpin455]

I agree Bob, and piston speed is one of the things that is detrimental to a 455 with the long stroke. Let me tell you that is moving that piston and heavy 6.625" rod quite a ways really fast. Guys go to 428s with the 4" crank or 400s with the 3.75" to limit it depending on what they are doing with the heads and cam. My 467 has a 4.25" crank and a 4.181 bore, and it will go 7500 easy, that is some seriously high piston speeds, and it has the parts needed to survive that. It doesnt have to be shifted that high, but it will turn it and still make power. That is the beauty of a nice flat torque curve that has 500ftlbs just above idle and over 650 between 4000 and 5500. It still wont hook.

Todd - keep in mind a lot of folks on other forums are regirgitating what some parking lot expert told them, not anything they've actually ever DONE.

That is the root of my rant, people who know nothing leading others down the wrong path. They are vocal and persistent too, even when called out and proven to be full of it. Why cant they just sit back and learn instead of trying to push something they know nothing about? That is why i go to forums, to learn new stuff and help out people who are doing the things I do. I dont tell them how to build chevys or mopars because I dont build them. I can, but I would be asking someone who does it all the time for advice.

I for one am sick and tired of herd mentality. I dont even follow the herd in the Pontiac world, who else is running GTOs on home brew? lol

What works for one engine, doesn't work for all. However, keep in mind:

For any engine- more RPM means more air and fuel taken in per unit time and burned and more power produced. An engine converts chemical energy to mechanical energy. The more you put in, the more you get out.

However- it also depends on the heads and how well they can flow. An Olds head doesn't flow very good. And as for the 403 olds, it has a 3.35" stroke- pretty short and not great for torque but good for minimizing the piston speeds and stresses in the engine. But due to the heads, it runs out of steam pretty early in the RPM range.

I have always heard the best gear for a drag car is the one that gets the engine to the redline at the finish line.

True the stroke is short in the 403, they use the same cranks as the 350s. The difference is the 4.351" bore. The only passenger car engine with a larger bore is the Ford 460. The 454 has only a 4" stroke but they can grunt very well too with the right ports, because they have a big bore. They have to get the displacement somewhere when they have a short stroke, and the bore gives it more surface area to push on. The longer arm moves the pistons farther with greater leverage.

If the 403 didnt have windowed mains like Spidey likes to point out, it would be a great engine for a stroker crank as it has room for it, and a huge bore. Plus big olds heads will physically bolt on. Nobody makes cranks for the 403, its kinda the red headed stepchild, and people trying to build them like the 350 sbc makes most think its a slug.

[Mater]

they do not have any cranks for any of the small block olds. or actualy the small mains olds. becuase the deisel small block used the big mains like the big blocks

[Grumpy]

I've read through this whole thread and tried to absorb it, all of these numbers are swirling around in my head and giving me a Migraine! My favorite combination that I use in my street & strip car is a small block Chevy with a 8.5 c.r. with a 3.70 gear and it seems to work well? Just as a side note in the "for what it's worth" dept. they used a bunch of the 403 Oldsmobiles in the FWD GMC & Revcon Motor Homes.

[Orange65]

You can use a 330 Olds crank in a 403- same stroke as all SBO's and they are forged. You can also offset grind a SBO crank and use a small journal SBC rod in them for more stroke. The 403 is very week in the bottom end.

[SpiderGearsMan]

As a point of reference, Top Fuel dragsters use 2.90 gears.

per the rules , they also have 9000 ft lbs of torque

[Brian Lohnes]

Details....details!

[TheSilverBuick]

I want 9000ft/lbs of torque :*( Haul trucks only have 6600ft/lbs or so =/

[TC]

per the rules , they also have 9000 ft lbs of torque

Don't forget they also turn 9000rpm and have a 33" tall tire, combine that with the 2.70 rear gear and you'll have a top speed of 327MPH........that's around what they run right??.........

[Thumpin455]

Well the tire grows quite a bit too, so the effective gearing changes at the top end. That is a crazy skewed example, but it fits with make enough grunt and it will pull anything.

[Beagle]

since all of the crap I build is built like it is for a tow truck, I see your point. I am the anti-thesis to Freiburger's "no such thing as too much cam, just not enough motor"

I tend to like things that will fry the tires without a line lock, power brake, or 5000 clutch drop when it comes to street stuff (which is all I really do, so that's the way I would build one).

Most of my real "hot rod", ie faster than 13.0 stuff was Mustang related and 4.10's with carb'd single planes, high compression, big cams, big / long tube headers and stuff will get you to the end of a quarter mile faster. First gear in a 5 speed with 4.10's won't make it through an intersection without having to shift.

I've got poop on the shelves for a GT40 manifolded EFI (about 13" runner) AFR 185 headed 393. ~9.5:1 with a 220* cam like an E303 or maybe as far as a XE274 (224*) with shorties and 3.08's for farting around town. It'd be close as to whether or not it would run on regular with any amount of base timing... (like 12*). I was gonna use Edelbrock RPM's (~9.2) and a 208/216* truck Comp 2020 cam and put it in the Lightning, but I can't make up my mind... It's hell living in my head. Either one would probably be done by 5500, but work hard where I want it to (2500-4000)

I had thought about pulling the 4.10's for 3.55's if I do this for the truck. It's buzzy on the hwy above 75.

[yellomalibu]

I often ask a buddy of mine's opinion about car related stuff - because he knows a lot more about cars than I do. In the end, I still do what I want to because it's MY car.

Don't let what other people do to THEIR cars bother you man.

If you are a mechanic and they are paying you to install 5.13 gears, you should happily install them and thank them for their business.

As long as they aren't forcing you to do stuff to your car, you should be happy.

[A/Fuel]

Actually they are limited to a 36" tire with 3.20 gears and a rev limit of 8250, how much power or torque is anyones guess.

[TheSilverBuick]

Don't forget they also turn 9000rpm and have a 33" tall tire, combine that with the 2.70 rear gear and you'll have a top speed of 327MPH........that's around what they run right??.........

Think how much faster they'd get to the finish line with 4.11's!