So much for the big block. People here gave me a lot of info, and helped me see that it just wasn't going to be a good idea. The problem is that I'm still stuck with the desire for that big block style torque that hits immediately off idle.
So, how much can I stroke a small block without compromising its stuctural integrity? I don't care much about the bore or rpm. I want massive torque at any time. I also will not give up my accessories like a/c. I live in S Fla and I want my a/c.
I had a 70 skylark with a 455. I've been spoiled, as far as power goes, ever since then. It seemed like it didn't matter what I asked the car to do, it just did. No fussing, no whining, no crying. And it seemed like I never reached the end of its capabilities. It always was ready to do even more than I had asked, it seemed like. The question is, how can I get that with a small block. The s/c packages are designed to make most of their boost as rpm climbs, not from idle. At least that's how I understand it. Turbos have a massive hit, but below that rpm, they are kinda like stock.
Any ideas?

 

Awhile back, World products built a 454 small block ( 4.250 bore with a 4.00 crank). With 10:1 compression, Motown 220 heads, Crane flat tappet cam ( 252/260 .536/.554) with 112 LSA made 596 peak TQ @ 4500 and 607 peak HP @ 6200.

 

different superchargers are set up for differnt applications. A roots blower will give you power from idle I think. And a centrifugal blower, wouldnt be far off.

As far as stroking a motor it depends on if you want to use an OEM block or an aftermarket block.

 

That sound like just the ticket. Can it be done with an LT1? I want to keep the fuel injection. Much smoother idle and better mileage. I think I remember reading something about that engine. If I remember, it was VERY expensive. Did it have a forged crank, rods, pistons?
Do you know what the stroke is with a big block 454? Did they have to use siamesed cylinders to get that bore? I really don't care that much about final displacement, but I really want a lot of stroke in there.
Thanks for the info. Nice to know it can be done.

 

The longest practical stroke for an LT1 is 3.875". At 0.030" over it's 395ci (often called 396ci). It's possible to use a 4.00" stoke crank and get 408ci at 30 over (often called 409ci) but this is much more of a project in terms of clearancing, use of small base circle cams, etc. Ditto and more for even longer strokes.

A 396 big block Chevy is 4.096" x 3.76" bore and stroke and a 427 is 4.250" x 3.76", so even a lowly 383 has as long a stroke as a smaller big block. The low end torque you felt with your 455 was as much a result of the cam and intake as anything else. Did you ever drive an L98 TPI? The low end torque was phenomenal for this 350, but it would run out of breath at less then 5,000rpm. It had long intake runners and a small cam as well as relatively small intake ports. Great low end, not anything up top.

If you want small block with huge low end torque, you might look into positive displacement blowers. As was suggested, they give huge torque from idle.

Rich Krause

 

The stroke and bore of a 454 BBC is the same as the above SBC. This motor was built with a Motown block, Eagle 4340 steel crank, H beam rods and SRP pistons.

 

its not on World's website yet, but a similar race version of that motor is in the new Summit Catalog.

World 427 small block crate motor
220cc intake, 13.5:1 compression, 1050cfm roller, motown heads

iron heads
650hp, 675tq
$9994

aluminum heads
675hp, 685tq
$10,494

id guess with lower compression , it would be about the 600hp you said.

 

Thanks for the info on the prices. It's a good bit more than I want to spend, though.
People keep on mentioning positive displacement superchargers. Isn't that a roots type or maybe a screw type? Those don't clear the cowl, do they? If they make one that does, I'd be very interested.

 

Thanks for the stroke info. I definitely want to stay with the LT1, and I want to keep the cost down if I can. I want the fuel injection and the ability to tune it in software. No carbs, thank you. I guess I'll not be going any higher than 396 cu in. I'd actually rather bore it as little as possible.
Any idea what a good forged stroke kit might run? I looked at summit and didn;t find it. Maybe I'll call them, just to see.

 

call one of our forum sponsors and they can put together a good stroker package for you.

383 is the cheapest and most common, with all forged components the kit would probably be around $1200-1500.
or you can buy the whole assembled short block for around $2500-3k.


396 is the next setup up, but the crank cost a lot more, so expect to spend more.

the power is really in the heads, so i would get the 383, and use the money you saved to get some really killer heads.

 

That's probably how it will work out. Sigh. I want lots of stroke, but it ain't free or even cheap. I was kind of hoping it had gotten a little cheaper to get a longer stroke, but I guess not. I guess it'll end up (eventually) a 383 with the sts turbo setup. That sounds like the bang for the buck deal to me. I just wish there was some way to get a positive displacement s/c under the cowl of a firebird.

 

Someone on here has fit a M112 Eaton (roots type) SC under the hood. I can't remember his name anymore. He made a custom intake manifold and it looked like a nice setup. So it can be done.

EDIT I think his name was Rooster and it fit under a stock hood. Do a search and you'll find his website with pics and stuff.

 

Do you remember how it worked out for him, or how expensive it ended up being? (Do I want to know?)
Did it fit under a stock hood? I really don't want to have to buy an aftermarket hood.
I'll try a search tonight. No time right now. Thanks.

 

Once you start looking into rotating assembly prices for a huge displacement sbc stroker, the $400 or so bucks for a hood will be the lease of your monetarty problems

 

I want to keep the stock hood for 2 reasons. #1 My funds will probably never be unlimited or even bear any resemblance to it, so my money needs to go into drivetrain related things. A roots would be nice, but after I spend money for the hood AND getting it painted then it adds up. I also wonder about fuel delivery with the roots blower. I really want to keep the injection. #2 I want to be as stock looking as possible. Just another LT1. Nothing to draw attention here. Move along, move along.
I'll probably have to go with a 383 instead of a monster stroker as well, because of the funds thing. I was hoping large stroke packages had gotten a little more affordable. I guess it's not to be.