Well, the teardown on my motor wasn't pretty. Still not sure what the initial failure was, but it needs a complete rebuild. I am thinking that I don't want to build another LT1 and am contemplating a big block Chevy or a Gen I SBC. As with the LT1, the car will be set up as an extremely fast street car that also goes to the track. So, it has to run on pump fuel (though I can get 100 octane unleaded from the pump and am willing to use that on the street).

To acheive my performance goals I had the LT1 set up with a Procharger F1. At the track, I used a small shot of nitrous to make up for the relatively weak low end and the weight of the car (over 4,000lbs with driver). It was capable of nines, but I never made an all out banzai pass because the track management made it clear that if I hit the nines I was history (just a 6-point bar, no cage). It ran 10.22@140+ and I want to go faster (of course). So, I may do a cage if I need to.

What I am thinking is that with a bigger cube motor I could ditch the SC with the attendant packaging/tuning/increased IAT issues. Run it NA on the street and add nitrous and race gas for the track. I already have the drivetrain parts and a mondo fuel system and plan to use EFI, probably an Electromotive TEC3. If I go that route (NA street/N2O track) I am wondering if a small block will make enough HP in the "street" configuration? I need in the 650hp range to get the street performance I want. And it seems to me that if I go small block, I will need the 'charger for that. OTOH, I already have the Procharger and a small block will package easier and be ~150lbs lighter. An aluminum BBC is out due to the very high cost.

So, I am looking for input on the issue of the two configurations for a 4th gen: a Gen I SBC with Procharger (and small nitrous shot if needed) vs. a BBC NA for the street and with nitrous for the track.

Any input will be welcome. Cost is always an issue, but a couple of $K either way will not be the deciding factor.

Rich

 

I havent even gotten my turbo motor in, and I'm already piecing together my all aluminum BBC. I like the BBC idea, just cause its unique, and you can make BIG BIG power NA, then just throw a DP n20 setup on it and hell you could easily hit 8's IMO.

P

 

You can make 650hp with a large small block and it's not that difficult to do. I've been over the costs of building both... lots of scribbling, $ signs and stuff numerous times. The conclusions I've come to are these... building a big small block vs building a 540-598ci big block aren't that far apart.

By the time I get my small block short block put together I've got ~$5k in it. I can put a 572 or 598 BBC together (short block) for about the same price. The heads for the big block are going to be a bit pricier... but that price is about equal if you're looking to use a SBC race head.

Granted, a 572-598 BBC making 700hp is going to be a mild engine with great street manners. The smaller cube SBC is not going to be too "race" but at the 650hp level... it's a "hot street engine". The better the cylinder head, the milder the camshaft can be and make great power. A 434 SBC will swallow a 255 @.050 cam real nice like and you get down to something with 10º less duration and it gets real mild. Can still go 625-650 with something like that and a great head though.

Personally, I'd take the weight break. But you can't deny the potential of the BBC. It (572-598ci) could go 750hp and still be very streetable.

-Mindgame

 

What's the story on the blowup Rich?

 

Are you looking for it to handle well? I remember a while ago a discussion about possibly autocrossing your car or something to that effect. If super-great handling isn't a concern, just throw the BBC in a be done with it. I can imagine the maintenance would be much less for a BBC at 750hp than a small block with less than that.

 

It was more of a "meltdown" than a "blowup". Lost oil pressure and I am still not sure why??

Rich

 

No auto-X, just high performance street and occasional strip use.

Rich

 

Glad the BBC bug I placed took hold.

540-572+ BBC would be a good street motor IMHO.

Both the SBC and BBC would probably use race style heads, so prices are going to be relatively high for both.

A 18 deg BBC head would be very helpfull because higher compression ratios which are needed to pull of a NA motor are achived better with a more compact smaller chamber, which will work better with pump gas. The interesting thing is that 900-1000hp NA is doable then. A 900hp 572 is the same HP per cube that a 700hp 427 is or a 600hp 365. A 1.6-1.7 HP per cube rule would be very driveable still, so more cubes mean more power here.

I'm not going on the cool factor, but on the total cost factor and swap factor. You have to go with a different cooling system setup with the SBC or BBC, and since you have the F1 it's worth something and if you don't have to use it later on a BBC.

I don't even know if you have to use the N2O for where you want to be if you go BBC. The car should be strong enough NA to get you into the 9's without any helpers, mostly it's just good heads. Well that and a SR because it's a BBC.

Bret

 

Might want to consider the Gen 1 SBC, with a 2-stage nitrous system. 125-shot for the street, another 150-175 for the track. You could be looking at close to 550 on motor - pretty mild, 675-700 with the little shot and 875HP with the big shot.

That's basically the way I started out... but then the NJ "mobile emissions" inspection shut me down as far as street driving, and now I'm sort of "stuck" with a car I can't really drive on the street - even though it would pass rolling emissions, and isn't fast enough for the track.

For a street driven car, I would think the SBC would be a lot more manageable than the added weight of the BBC.

 

Is an aluminum BBC out of the question? I know Trickflow, Brodix, and a maybe even Keith Black cast one with a plethora of different options. Not too long ago in HOTROD magazine there was an article about an ~620ci aluminum bigblock that was fuel injected. It was VERY conservative and made well over 700hp.

 

Rich mentioned in his 1st post that an aluminum BBC was out of the question.

Sure, if money is no object you could use the Donovon 5" bore space block and build a 760ci BBC. The limits of the imagination are infinite... just not the pocketbook.

-Mindgame

 

Just out of curiousity, how much more does a BBC weigh than an SBC???

 

Figure a ~150lb constant in that formula .

Ryan

 

Big cool factor to an Al big block, for sure. A bare block is in the $4,000-5,000 range though. There is ~90-100lbs differerence in the bare block weight between a BB and a SB. An complete BB weighs ~150lbs more than a SB. Of course, I could leave of the SC and water injection, which would save ~50lbs.

It still seems like the pros and cons of each setup about cancel each other out. I am leaning toward the big block though. Build it with the BB, see how it runs, add nitrous "to taste"?

Rich

 

That's what I'd do. And sell the F1 to help fund things.