Sell me on your favorite big block V8.

A word of caution on some, if not all, BB Chevs. The crank thrust bearing is actually part of block (i.e. no separate replaceable bearing). Damage to that part of the block (usually due low oil level, or low oil pressure) can be expensive to repair (or was back in my day).

https://www.chevydiy.com/complete-history-chevy-big-block-engines/

¯\_(ツ)_/¯ said:

Is there anything neat about the newer GM 8.1L?  I like the one in my truck so far, and they're not incredibly uncommon, but I'm also not sure if they have any more or less performance potential than something like a 454.  It's tempting to assume that newer=better but it was probably only ever designed to be a truck motor.

They're a lot like a 4/3 scale 6.0.  Coil near plug, engine sealing theory from the 2000s instead of the 1930s, dry intake manifold with the throttle body axial to the barrel, only one intake and one exhaust port instead of 1 exhaust and 2 wildly different intake ports, etc.

The most interesting thing about them, to me, is there are no PCV hoses.  The crankcase breather system is a 1/8" hole in the intake manifold going to the valley.

Pete. (l33t FS) said:

¯\_(ツ)_/¯ said:

Is there anything neat about the newer GM 8.1L?  I like the one in my truck so far, and they're not incredibly uncommon, but I'm also not sure if they have any more or less performance potential than something like a 454.  It's tempting to assume that newer=better but it was probably only ever designed to be a truck motor.

They're a lot like a 4/3 scale 6.0.  Coil near plug, engine sealing theory from the 2000s instead of the 1930s, dry intake manifold with the throttle body axial to the barrel, only one intake and one exhaust port instead of 1 exhaust and 2 wildly different intake ports, etc.

 

The most interesting thing about them, to me, is there are no PCV hoses.  The crankcase breather system is a 1/8" hole in the intake manifold going to the valley.

I've always described them as the "LS version of a big block Chevy". Definitely a cool idea.

Dream big block for me is a Cad500 with ported 425 heads.  Perfect street terror and an easy 450 hp for a very small investment that idles like a purring kitten.

At least no one has said Pontiac or AMC "big blocks" yet or I would have to slap them up aside the head. That's one of my personal pet peeves.

Also, what's the worst big block? Oldsmobile would have to be my first choice. They have pretty fragile blocks, huge main and rod bearings, a terrible oiling systems It oils the valvetrain first and main bearings last, and there are no oil drainback holes in the bottom of the head, instead it has to pump the head and valve covers full and then it drains back down through the pushrod holes. And the valve angle is something wacky, like 6 degrees. Ford FE isn't much better. Dorky valvetrain, weak blocks, oiling system that is only so-so (unless it's a side-oiler).

I started to read this thread in anticipation of seeing Curtis and Keith commenting about the big Cadillac engines. Not disappointed. 

"false"

Earlier BBC thrust bearing failures often required welding up the crankshaft thrust bearing surface and then machining the CS thrust bearing surface as a means of a repair (which can be expensive and often was unsuccessful).

http://clubhotrod.com/chevy-big-block/43867-bbc-thrust-problem.html

Floating Doc (Forum Supporter) said:

I started to read this thread in anticipation of seeing Curtis and Keith commenting about the big Cadillac engines. Not disappointed. 

Everything I know about Caddy engines is: 

-my Cadillacs have them

- I scored a 472 off CL for $200 so I bought it. 
 

Everyone should be listening to Curtis, not me. 

In reply to Keith Tanner :

I am to Caddy 500s as frenchyd is to Shellac and Jag V12s.  I'm a fanboi.

Curtis73 (Forum Supporter) said:

Dream big block for me is a Cad500 with ported 425 heads.  Perfect street terror and an easy 450 hp for a very small investment that idles like a purring kitten.

I'm still blown away that Amir Rosenbaum, owner of Spectre Performance, took a streamliner to 348mph at Bonneville with a single Cadillac 500 with iron heads, stock block, stock crankshaft and twin 91mm turbochargers. With a more seriously built Cad 500, it has gone as fast as 415mph. 

I also remember a guy that showed up to Hot Rod Magazine's Pump Gas Drags (RIP) with a Fox-body Mustang that ran 9.50s on a nitrous'd 500 Cadillac with a stock crank.

BBC thrust bearings do not fail. 

Okay I'm out 

In reply to NickD :

Wait, 

What's the physical size difference between a cadi 500 vs an LS?

Do you think it'll fit in this same space? With a turbo? Lol

Man, I had two of them sitting side by side earlier this year and never thought to take a picture.

We're forgetting the only real option here.

Jaguar V12

If you want a real trip, google up some Cad 500 swaps.  Rear-engined S10, a 70s beetle with a Caddy 500 that does wheelies, G-bodies racing in the 10s.... there is some great stuff out there.

I just finished a video series where they did some bolt-ons to a 500... cam, intake, ported the heads, and ended up at 550hp and 620 lb-ft, all below 5000 rpms.

Google "Rocketbox"

A Caddy 500 swapped microbus I fellow I know built.

wheels777 said:

I have owned, raced and owned and raced BBF, BBO, BBM, BBP and BBC. 

BBC is your best answer.  Cost.  Power per dollar.  Power per CI.  Reliability.  Part availability.  Oil system reliability.  Crankshaft stability.  Transmission cost and adaptability.  Aftermarket support.  Journal diameter.  Block stiffness.  Head flow. 

You've obviously never raced a Cad 500.  Buy $200 junkyard engine, port the heads, stab in cam, upgrade the rockers, and you're at 450hp/600tq for less money than just the heads you have to buy to get the BBC to those numbers.

Up to 1hp/ci, the Cad is the same or cheaper than the BBC

yupididit said:

In reply to NickD :

Wait, 

What's the physical size difference between a cadi 500 vs an LS?

Do you think it'll fit in this same space? With a turbo? Lol

It will fit in the same way a Walrus fits in your carry-on luggage.

ShawnG said:

Big block / small block implies physical size differences therefore:

409 = not a big block, just a wheezing truck engine with a bad chamber design. Don't let the Beach Boys fool you.

The W is considered, at least by some, the first gen of the Chevy big block motors. Besides bigger displacement than the 396 and 402 it shares some identical block dimensions for instance – cylinder bore spacing (4.84”). I will leave further research to you.

Curtis73 (Forum Supporter) said:

The Beach Boys had to come up with something to rhyme with "409" but "perfunctory" or "just ok" didn't fit anywhere in the lyrics.

"She's real fine" was very apropos 

In reply to L5wolvesf :

I know all about the 348 / 409 W-motor family.

It's bigger than the SBC but it's an evolutionary dead-end. 

The 400 SBC has more displacement than the 396 BBC but that doesn't make it a big block.

Curtis73 (Forum Supporter) said:

Dream big block for me is a Cad500 with ported 425 heads.  Perfect street terror and an easy 450 hp for a very small investment that idles like a purring kitten.

I'm going to be stripping down a 425 here soon.  Want the heads?

yupididit said:

In reply to NickD :

Wait, 

What's the physical size difference between a cadi 500 vs an LS?

Do you think it'll fit in this same space? With a turbo? Lol

For the Cadillac you can also get front and rear factory pans.  Just the rear sump is rarer and more money.  I have mid and front if you want one.

Since Curtis is making the sales pitch for me I have a bunch of Cadillac 472/500 stuff I'm willing to get to a good home.  Travis got my 500 crank as his first place trophy though.