Big Block

[Brandon_Charley]

We're building a Class 8. We don't have a big engine budget so we need the most power for the cheapest price. I'm pretty sure a big block would accomplish this. What kind of actual weight difference is their between the blocks of the sbc and the bbc. Are they close enough that lightening other parts of the front end could make up the difference? What do you think the best front to back weight distribution we could hope for with a BB?

Thanks,
Brandon

[Ramsey_ElWardani]

You have a lot of questions, and this is a good place to ask them, but may I suggest that you spend some time around and with a current Class 8 team to get a better feel for what you are getting yourself into. Regarding the BBC, with Aluminum Heads and Intake Manifold you can get the weight to about 100 lbs more than a SBC with similar parts. The real question is if a big block is legal in a ½ ton frame or if you need to use a ¾ frame. I’ll leave the answer up to your imagination.

[Brandon_Charley]

As far as the rules go, from what I've gathered from the other class8 guys on the board is that the people who actually race the class seem to have their own set of rules that they have tried to get SCORE to use. Pretty much, as long as your block is the same material as stock, your frame isn't modified (except for front 8"), and everything is the same manufacturer your legal til you win, which I don't expect to do for a long time.

[Josh_K]

I would advise you to take Ramsey's advise and get close any of the class 8 that are in your area. We are all nice guys. I never meet a jurk that races this class. Furthermore ask Klause to get you on the Class8Colition mailing list. Its not the greated thing ever but we are all on it and this is where we sometime discuss things.

Josh

[Brandon_Charley]

Where can I do that?

[Josh_K]

BTW. If you are on a buget go with a nearly stock big block. Spin it slow, keep the compression down and use the torque to move the truck.

[Josh_K]

Find one of klause's post some where on the site and PM him. It's his site and I belive he can set you up. Other wise go the thread about Score roll bar rule change and PM JimPat (Jim Patelli 8 trk racer) and he can get you on.

Josh

[UndercoverFab]

go with a 400 with some vortec heads and a hydraulic roller, let the 500+ ft lb`s of torque keep ya moving.

if its in the budget some afr`s would really wake a mild 406 up.

[Brandon_Charley]

Is anyone driving a class8 with a big block now?

[Josh_K]

I can’t think of one. If you went with a mild 454 and maybe even built it to burn 91-pump gas it would be cheap to build and operate. If you are worried about getting busted on the rules, don’t know one cares. Plus, if you are like me you will blow up a few engines trying to figure out how to care for and operate them.

I recommend that you don’t dump gobs cash it your first engine.

Josh

[scottm]

A low buck big block means iron heads and about 700 pounds. I say a 400 sb. Flat track guys get great power and reliability from 406 sbc's.

[Brandon_Charley]

Thats what I was thinking, if we try to build a 350 or 400 to the power that I've read others are getting its going to kill our budget, and we'll be screwed when we break it, so we were thinking of sacrificing weight fo cheaper power. light, strong, or cheap- I read somewhere else on the board that in offroad racing you get to pick two of the three we're picking strong and cheap.

Sorry if I butchered the saying.

[Ramsey_ElWardani]

There is nothing cheap in offroad racing. Take your time researching before you spend a dime or cut up a perfectly good truck. Where do you think all those ads for parts and unfinished projects come from.

[scottm]

If you want to run with Vanderway and Leduc you will need 600-700+ hp (which is still pretty expensive to get from a bbc too) and a crismann rear end. But you don't need that to have fun and finish. I am in the same low buck situation, so I don't plan to be competetive, just hoping to finish.

[UndercoverFab]

you could make a reliable 500 for under 5 grand on pump gas if you do the assembly yourself.

[FABRICATOR]

If you went with a mild 454 and maybe even built it to burn 91-pump gas it would be cheap to build and operate. If you are worried about getting busted on the rules, don’t know one cares. Plus, if you are like me you will blow up a few engines trying to figure out how to care for and operate them.
Josh LMAO...
Big blocks rule!! But it's not easy to take advantage of their strengths off-road. If you're talking Chevy, the iron rat motor is a heavy beast but the torque available is significantly more than any small block (mouse) motor. Achieving 500 ft lbs at around 2000 RPM is a no brainer. No need for the destructive high-stall converter either. As mentioned it can run on pump gas and would likely get better mileage overall. Building one for higher output is a waste of time because it will tear up any driveline. If a driveline could be built strong enough there would be chassis torque problems. If you can live with the weight and keep her cool, it would get the job done for a whole season with little more than a couple of oil changes.

[Brandon_Charley]

Ok, at this point since their seem to be more people saying its possible than not, I think I want to do it for no other reason than the fact that no one seems to have tried it. On to the next question, does anyone have ideas on how to move some other weight from the front of the truck to the back to equalize the weight distribution?

[FlyHiFlyLo]

IMO, if you are looking to run a SBC in the end, go with an SBC from the start. All of your accessories pumps, alt, water,headers will nickel and dime you to hell on any build. You can build a 434 Dart SBC long block easily on e-bay for under 5K. If you start with a mild 350 or 400 shortblock then you can do a great top end (big Dart heads, manifold and all the other goodies) for about 3000.00 on e-bay making 425hp-475hp. Then when you step up to a Dart 434 or 454 SBC short block (about 3500.00 on e-bay) your entire 350-406 package including cam, oil system, belt or gear drive will transplant making well over 550++HP.

The only thing that will not work on the new big short block is the pan. Unless you start with a big stroker pan on your first build. I recomend this because you don't want to weld yourself in a corner.

When starting out big power can get you in trouble. Get some decent power and dial in suspension first. Then add power as you add reliability to your entire system.

An all iron 350 is 550 lbs, All Iron BBC is 750lbs, 200 lbs is huge off the front end. Aluminum heads on an SBC is 60lbs savings BBC is 90lbs

By the way. Keep your compression to under 10.25:1 on anything you build. Pump gas is the way to go budget racing.

Just my theroy. I have thought about this class many times for many years.

[ChuckH]

A big block is the 1st choice of the class 1 design i have that i hope to build when i get more time off, the crate 502 isn't priced to bad (5000) and should last a few races, fab is right put a low stall converter in it and the tyranny will last much longer too, it can run pump gas also like he said, im looking at something i can race without rebuilding totaly each race.

Whats a extra 100lbs on a 4000lb or more car/truck, nada, if your creative you can design that out.

[ChuckH]

On to the next question, does anyone have ideas on how to move some other weight from the front of the truck to the back to equalize the weight distribution?

Easy put the battery by the rear bumper, if you get creative you could easily off set that 100 lbs, mount the shock reservoirs as far back as you can, the oil cooler, water cooler and so on.

Use the Hemet shock mounting setup :p
http://www.race-dezert.com/forum/showthread.php?t=12739&highlight=hemet

[ntsqd]

Were it me, I'd buy a mid range crate SB or build something similar. A BB would give you the durable power, but the weight penalty is too great.

[ChuckH]

Were it me, I'd buy a mid range crate SB or build something similar. A BB would give you the durable power, but the weight penalty is too great.

Go on a diet and if your a two seater find someone who weighs less than 125lbs ;)

Problem solved :D
in my case i want a single seat car so that eliminates the 100+lbs many class 1 cars carry with two people.

[Brandon_Charley]

THat actually applies, I'm on a diet and my co driver is a stick!

[ChuckH]

http://www.gmgoodwrench.com/perfpartsjsp/partlist.jsp?section=ce&cat=9274

You cant go wrong with a crate motor these days, i trust them more that all but the top engine builders, get a biz lic and and you can buy them wholesale, or maybe a find a friend that can hook you up.

[Ramsey_ElWardani]

I think I want to do it (BB) for no other reason than the fact that no one seems to have tried it.Maybe there is a reason no one is doing it, besides the rules, of course. Actually I know of two BB Class 8 trucks, both Fords; one is legal (F350) and one is not (F150). What are you building, Ford or Chevy? I assume Chevy because of your referencing "bbc" and "sbc" but you haven't said.

[Brandon_Charley]

Yeah its a chevy. If no one else in the class cares about the rule then what does it matter?

[Ramsey_ElWardani]

How many people in the class have you talked to?

[Brandon_Charley]

Just people who answer my questions on the forum, which is not everyone, I understand that.

We haven't bought our frame yet, so if we get a 3/4 ton frame a big block should be perfectly legal right?

[FullsizeFun]

I think a GM crate motor would be the way to go. Probably under $5k with carb, headers, etc. This 383 has 425hp. thats a decent start for the price.

http://www.gmgoodwrench.com/perfpartsjsp/partdetail.jsp?cat=9274&sku=12498772&section=Crate%20Engines

[ntsqd]

For the first engine I don't think I'd even go that high. Unless you've got lots of seat time already, I'd be looking for something more like 350-375 HP It'll be easier on the budget too. Just buy it knowing that you'll want to upgrade when you driver & suspension tuning skills exceed the HP available.

[Brandon_Charley]

I have been going over the rule book and I'm not sure where exactly it says I can't run a big block in a 1/2 ton? If its the "engine type" part, a 454 is still a pushrod V8. If its the "original block casting" part, not all chevy trucks came with a 400 block, and not all fords came with a 351w, so I wouldn't be the only one breaking the rule.

Do you have to win the class, or just finish ahead of someone else, to worry about someone protesting? If someone does protest whats the worst that can happen? Whats most likey to happen?

If you can't tell I really want to run a big block, I think solving the weight distribution problem could be really fun.

[FlyHiFlyLo]

The years you stated you are running you could order a 454 in a half ton...You are in the rules.

[jeff]

The 1990-1993 C1500 with the SS package had a 454. It was only available in a standard cab option and there is around 16,000 of them on the road. So running the 454 in a Chevy 1990-1993 body style truck should be legal as far as any rules I've read are concerned. For the size of the engine the SS trucks were pretty slow and handled so-so at best. Again, that BBC weight penalty over the front end was hard to overcome.

Aloha

[ntsqd]

One other thing about the SS trucks is that they were only available as short beds, no long beds. So to be technically precise a truck of that era would need to be std cab short bed to be legal.
I do know of ONE extended cab SS truck floating around So CA somewhere. Is a perfect SS in all aspects but is an extended cab shortbed and was built by a friend of mine to tow his Toybox.

[Stephen]

Holding the power/torque with the drivetrain and driving with it will be different for sure. I have a BBC in a general offroad crawler K5 and it's easy to break stuff where SBC guys just flat can't. I can also accelerate faster which can get me into trouble.
No matter what, more weight over the front is just that, more weight over the front and it's hard to control in that position. With a BBC, the weight is also higher which causes problems with handling also.
I'm looking at switching to a SBC but I already have a multi port EFI, alum heads, a roller cam and rockers and a set of jba headers all of which I'd prefer not to replace. This is what someone above mentioned concerning starting with a SBC so that upgrades still fit the chassis, etc. We started adding stuff as we found it and/or needed it and now I'm kind of stuck with it. Now I get to plan a drivetrain to hold 600hp...

That said, you can get silly power and torque without wrapping the motor very high, the torque off the bottom is really nice and reliable and non-peaky, and it will be very reliable at the 500hp level, or even lower power levels. And if you decide you want to make more power, there are many cubic inches and much more power available in the same package. Make sure you address the cam durability problems, I'm not a bbc expert but that's the reason we ended up with a roller cam in mine.

You've got to ask youself: why doesn't anyone else run a big block?

[movindirt]

How about putting the tires way out back to offset some of that BB weight? I have my tires way back (see pic) and I love the way it works, but that just me.

[Brandon_Charley]

Stephen, I don't understand what you mean about accelerating too fast. And, what types of things can a big block break that a small block can't? Just driveline or other stuff?

[ChuckH]

accelerating too fast.

Yeah you wouldn't want that in dezert racing, it would take the fun out of passing people. :D

dezert racing = ditch to ditch drag racing.

[Bill]

he was talking about it in his crawler.

[ChuckH]

yeah i knew that, were talking about Dez racing and my point was to that with a little humor, notice i was talking to Cracka

[Ryno]

I'm in agreement on the SBC. The mouse motor parts are the same, and they are dime a dozen. You can get a set of vortec heads from Scoggin-Dickey for about $300. These are the best flowing iron heads from the factory. You could potentially put together a 300hp SBC for 1500-3k if you shop around for your parts. Keep in mind, a turbo 400 will handle all the power from an SBC pretty easily with minimal working from a tranny shop. You could pretty much bolt up a chevy driveline to a build 9" rear end, and have it last a season of racing. You won't be the fastest thing out there, but you'll be out there, not worried about the 5k you sunk into a motor if it blows up.

[Stephen]

Stephen, I don't understand what you mean about accelerating too fast. And, what types of things can a big block break that a small block can't? Just driveline or other stuff?

Drivetrains get worked harder with more power. With 350 horse, (as mentioned elsewhere here) a TH400 is loafing. With 600hp, the trans builder better start paying attention. Ditto for the rear end. The weight will be harder on everything in the front suspension. No matter how you slice it, you're going to have more weight on the front. Everything you could move with the BBC, you could also move with the SBC and end up even lighter.
Moving things to the extreme end of the chassis helps the static weight bias but is hard on the rotational moment of inertia. With the tires right behind the axle, when the rear kicks up it will stop moving up sooner than if your tires are mounted 4 feet farther back.
Chuck, my problem is/was going from ditch to ditch thinking "maybe I can do this just a little faster" and end up going a lot faster and POW the truck is broken. It's really an experience thing. I've learned what the torque can do in low range, going fast is obviously another story.
Knowing you can really pull out of a hole does make it mentally easier to slow down for rough stuff.

[Brandon_Charley]

Okay, I have listened to everyones advice, and am going to ditch the class 8 idea, its just not smart, I have no experience and even less money. So, I am going to take Paul's advice and race 1450. I want to build a beam'd ranger with a built 351 pushed back.
Thanks for your help, you saved me a lot of time and money.

Brandon