Author Topic: BB Cubes in a SB package? (Read 2526 times)

HemiDog · « **on:** May 14, 2004 - 03:43:35 PM »

I was watching an episode of HorsePower TV a while back and the subject of the show was a Shafiroff 472ci small block. The performance numbers on this motor were pretty impressive and it ran on pump gas!
Anyway, this got my mind thinking about my project and so far I have been doing body work and haven't decided on a motor for the 71'. I have always wanted a 426 and this was going to be the project to put it in and I have been leaning that way. But the idea of the Shafiroff motor has me questioning going that route.
My big question now, is there anyone doing this kind of thing with Mopars and if so, how radical has anyone heard of going and still being a reliable motor on pump gas?

72cuda · « **Reply #1 on:** May 14, 2004 - 04:23:34 PM »

Lots of factors make an engine radical, but for pump gas limits, you're looking mainly at compression ratio and cranking pressure.

Since an engine is an air pump, you want high pressure and lots of air capacity in the cylinders to make power.

Low-octane gas burns quickly and unevenly, especially in high compression situations, causing detonation.

Here's a real good article on the theory, hang in there through the math:

http://victorylibrary.com/mopar/cam-tech-c.htm

Basically, if you limit compression ratio and cam timing to stay within safe cylinder pressure limits, you have to rely on other factors to make big HP. Like displacement, which is one reason why stroker motors are so popular.

And there's quench, and ignition timing, and intake/exhaust flow - it gets complicated quickly.

Mopar Muscle just got 600+ HP put of a BB stroker wedge on 87 octane dishwater, which is amazing. It's harder on a SB, though not impossible.

There's no replacement for displacement.

lemonboy69 · « **Reply #2 on:** May 14, 2004 - 07:55:40 PM »

One thing caught my pretty quickly on the original post... a 472 CID engine is by NO means a small block engine... Of the Big 3, I think the largest small block was Chrysler's 360... sure, there's the 383 also, but that's the baby Big Block..

Please, by all means, correct me if I'm wrong here, but this is what I've gathered and been taught!!

LB

Pistol Gripper · « **Reply #3 on:** May 14, 2004 - 08:16:56 PM »

LB,

By boring and stroking, you can get a 318 up over 400 cubes. I guess at that point "small block" would be a misnomer, but it's still a SB motor. My assumption is that any motor based on the 273, 318, 340 or 360 block is a SB. 361, 383, 400, 413, 426, 440 would be a BB.

Still, 400 cubes is 400 cubes

P.G.

oldvamoparfan · « **Reply #4 on:** May 14, 2004 - 09:20:29 PM »

If a motor is built from a 318-340-360 block, then it is still a small block, no matter how far you take the CI. Chrysler made a 350 big block back in '58m mainly for the then limited production Fury. So they had a big block that was smaller CI wise than a 360. They also made 241 CI Hemis. It was still a huge engine externally, especially w/ the enormous Hemi heads. Ford made 331 big blocks, Chevy made 348 Big Blocks, all Pontiac- Olds-Buick engines were big block w/ displacements as low as 300 ci, (excepting the aluminum 215 ci V8 in very early 60s.) The external dimensions of the block are what makes it a big or small block. I have a friend who has a '65 Barracuda w/ a 340 block stroked to 440 ci, w/ approx 850 HP on gas, plus it has a 350 HP nitrous rig. He won New England w/ it 5 yrs ago w/o nitrous. Ovmf

oldvamoparfan · « **Reply #5 on:** May 14, 2004 - 09:27:19 PM »

PS to LB, Chevy had a production small block 400 for a number of years. It has become a popular way for guys in stock classes to cheat when they are only supposed to run 350 CI. It makes quite a bit more torque than a 350, or any other small block Chevy. Also, a sb 400 crank in a 350 makes a 383 ci sb, & this too is much better than a stock 350. They made a sb 400 & a bb 400 at the same time acording to their ads, but the bb was actually a 402. A sb 400 looks just like any other sb Chev, even the 265 ci version. Ovmf

1973challenger360 · « **Reply #6 on:** May 15, 2004 - 04:51:40 PM »

amc 401

472 sounds cool but I dont have a caddy, get a 474

look at the September 2003 Mopar Muscle the landlord
71 demon running 340 r3 block 4.375" stroke 6.3" rods, w9 heads, 11.5:1 producing 474ci that a big small block

with a 904 with a 3800 stall 11.5" tires and a full interior with no power adders at 2400' at the vegas strip show 9.95 at 13.69

HemiDog · « **Reply #7 on:** May 16, 2004 - 04:24:02 PM »

Oldva has the idea I am talking about.

I know 472 is big block cubes, but the physical engine block on this particular motor is sb dimensions.

I found the link to the motor I am talking about and found out that ther start with an aftermarket engine block to help out the cause.

http://www.shafiroff.com/472_675_engine.asp

Now I have to go see about getting that Sept. 2003 Mopar Muscle.

DodgeFreak · « **Reply #8 on:** May 16, 2004 - 09:05:26 PM »

I have an artical in a mopar mag and they took a 360 bored it insanely big (they checked the block and all that good stuff before hand) and then stroked it and was making huge HP numbers and Huge TQ numbers i'll get all the facts later...but it was awesome..i know i'm a little vauge on the details but its been awhile since i read it.

oldvamoparfan · « **Reply #9 on:** May 18, 2004 - 09:36:11 PM »

The cost gets pretty high on these maxed out sb engs. Stroker kits are expensive, & there is usually a lot of machine work involved. Then you still have small valves & ports, compared to a 440 that is. There are things to do to help this, but these are expensive too. But, once you get past the money part, there definitely an advantage to the smaller exterior engine package Back to the money. If you have even a relatively strongly built bb, it will still be cheaper to build & maintain than the sb. Every single piece the big sb has is a specialty (read $$$$) part, w/ limited availabilty, ( not everyone in town is going to have it). It is still a tempting thing though. One easy route is certain 360 blocks will tolerate a fair amount of boring (truck blocks I think). A 360 bored .060 makes a 372 with out even having to storke it. A little massaging of the heads & a good cam & carb makes a pretty good streetable eng. Just a thought if you arent planning to put 10 or 15 K$ in your eng. Ovmf

brotow · « **Reply #10 on:** June 29, 2005 - 09:26:45 AM »

Someone out there looking for a 472 caddy motor? I believe I have one. Brotow@optonline.net

Author Topic: BB Cubes in a SB package? (Read 2526 times)

HemiDog

BB Cubes in a SB package?

72cuda

Re:BB Cubes in a SB package?

lemonboy69

Re:BB Cubes in a SB package?

Pistol Gripper

Re:BB Cubes in a SB package?

oldvamoparfan

Re:BB Cubes in a SB package?

oldvamoparfan

Re:BB Cubes in a SB package?

1973challenger360

Re:BB Cubes in a SB package?

HemiDog

Re:BB Cubes in a SB package?

DodgeFreak

Re:BB Cubes in a SB package?

oldvamoparfan

Re:BB Cubes in a SB package?

brotow

Re: BB Cubes in a SB package?