Sell me on your favorite big block V8.

GIRTHQUAKE said:

Curtis73 (Forum Supporter) said:

While I have nothing against the 472, the 500 is the same engine and the same price for 6% more cubes and 2000% more bragging rights.

Only problem is getting the 500 lmao

I know that the caddy 500 crank can be trued down 0.300" to accept BBC rods- and thus, suddenly jump to 541ci and cheap parts. Cost wise I'd much rather go for rods and pistons than mess with aftermarket heads- are there similar things can be done with the Ford 460? I'm pretty sure the smog heads can be bored out heavily and it also has a wide range of aftermarket stuff.

How does changing the rods change the displacement?

In reply to Keith Tanner :

Offset grind.  If you are cutting down .300", in theory you can offset the journal as much as .150", for a .300" increase in stroke.  

The actual amount will depend on what piston pin heights and rod lengths you are working with.

Ford 315s used to be popular in the 80s.  Ford 2.3 rods in a 5.0, with just a little bit of offset grind.  It wasn't enough to upset the computer but it was an easy whileyou'reinthere, comparatively speaking.

ShawnG said:

We all know the best big block is the Ford 300 big block six.

After all that nonsense with the Jag V12 showing up in this thread, I'm glad someone said it.

So it's not that you're changing the rods, it's that you're modifying the crank and thus changing the stroke. The smaller rod journal size means you have room to do that offset grind. Got it.

In reply to Pete. (l33t FS) :

Mini guys do this when making a 1275 into a 1600.

They also offset-bore the cylinders

It knocks the pin all the way out of the grenade though.

Keith Tanner said:

So it's not that you're changing the rods, it's that you're modifying the crank and thus changing the stroke. The smaller rod journal size means you have room to do that offset grind. Got it.

If you're modifying the crank, you'd have to change the rods, yes?  Otherwise you'd get like 4:1 compression or something stupid?

In reply to Keith Tanner :

Pretty much.  As a bonus, in this case you get to use big block Chevy rods, which is really popular in the aftermarket.  Not sure if cheaper rods would offset the costs of having the crank ground, and a rebalance, but hey, 8% more displacement!

Mr_Asa said:

Keith Tanner said:

So it's not that you're changing the rods, it's that you're modifying the crank and thus changing the stroke. The smaller rod journal size means you have room to do that offset grind. Got it.

If you're modifying the crank, you'd have to change the rods, yes?  Otherwise you'd get like 4:1 compression or something stupid?

Bigger problem would probably be when you ram the piston into the head thanks to the increased throw :) You could change the pistons with a higher wrist pin and retain stock rods if you'd like. The important thing is that the displacement change comes from crank changes, other things may have to change as a result. But you can't change displacement by only changing rods.

In reply to Keith Tanner :

Yeah, increased throw.  I thought about that backwards for sure.

In reply to Pete. (l33t FS) :

What you said.  The 541 is a pretty popular build in the high end Cadillac world.  They're so stupid good stock that most never get rebuilt.  As was said the combo is offset grind with BBC rods IIRC.

Mr_Asa said:

ShawnG said:

We all know the best big block is the Ford 300 big block six.

After all that nonsense with the Jag V12 showing up in this thread, I'm glad someone said it.

Keith Tanner said:

 

Otherwise I'd have to go with the Chevy simply because it was the go-to for Can-Am, and this is a legitimate intake. It's my understanding that the staggered lengths are due to variations in intake runner length in the head and not to spread out the torque curve. I don't care why, it's awesome.

We had one Jensen Interceptor owner build a 528 ci engine (based on the 440).  He found out where the line was as far as the 4HU Salisbury diff strength went (OK in a lighter 427 Cobra, a bit more delicate in a much heavier Interceptor.  Apparently very fast, mind you.

I just sorta realized that I've only owned two big block cars in my life.  My 66 Delta 88 had a 425, and I owned, but never drove a 68 Roadrunner with a 383.

Thats it.  I feel like I need something stupid.  The idea of a World Products 632 with a 24,000 mile warranty seems right, other than the cash involved.

As an aside, there is something about the way six thirty two rolls off the tongue that makes it my favourite.

In reply to Streetwiseguy :

I drove a 604ci Chevelle with a 4 speed.  The funny thing is it had 396 badges, because it was a 396 car.  "Is that a real number?" "Yes, 396 is a real number"

It was the final straw in turning me off of manual transmissions.  With the close ratio 4 speed you had to rev match UP when UPshifting because of all the engine braking.  The alternative was to shift faster/harder than I felt comfortable driving someone else's car, because I've also replaced a lot of broken Muncies for people who thought they were Ronnie Sox.

Be nice with an automatic.  Did a LOT of big blocks with automatics.  Former boss pointed out that it made no sense to build an engine smaller than 496ci because the cranks and pistons cost the same as a 454, and if you didn't need pistons and a crank, why were you wasting money rebuilding?  So I experienced a lot of 496s and 540s and a few 604s.

One of the last cars I did there was an all aluminum 565ci '69 Camaro.  It had a whole lot of suspension goodies (C5 Corvette front end, etc) and... a 5 speed Tremec.  SERIOUSLY?  You spend gigabucks on the engine and suspension and then get a K-Mart transmission?

In reply to Pete. (l33t FS) :

Everytime I see that video I start dreaming of midengine BBC goodness then come down to earth when I think about the transmission.

Cadillac is the answer there

Pete. (l33t FS) said:

In reply to Streetwiseguy :

Former boss pointed out that it made no sense to build an engine smaller than 496ci because the cranks and pistons cost the same as a 454, and if you didn't need pistons and a crank, why were you wasting money rebuilding?  So I experienced a lot of 496s and 540s and a few 604s.

Reminds me of a Hot Rod Magazine article where a guy had a shop build him a Boss 429 with the new Jon Kaase Boss '9 heads and intake, but the customer wanted it to displace 429 cubic inches so the shop had to spend all this time and money epoxying the intake ports on the heads and intake to get them the proper size so that it didn't run like E36 M3 at low speeds. And for what? You can't tell the displacement of an engine by looking at it, so it would have been cheaper and easier and made more power and probably been more drivable to make it a 514 or 521.

I've seen it go the other way too. A guy was all proud of the 396 block he got for free for a build, instead of spending $500 on a 454 block. Except piston options suck for a 396 and you're displacement-limited, so he would have been better of in the long run by spending the $500 for the 454 and then the sky is the limit.

When I worked for SASS (very briefly) I remember some guy brought in a true barn-find 69 camaro RS with something like 2000 miles.  It was even that semi-rare coppery/butterscotchy color with rally stripes.  The owner wanted to make it into a cruiser that got good gas mileage and wanted us to put a 4-cylinder in it.  I remember JJ getting up and storming out of the design room and start throwing wrenches.  A museum-quality piece that the guy took to a hot rod shop to put a 4-banger in.

Question for you guys; is the 425 block any different from the 500 it's based on? Light googling says no, but I want to make sure because I'm planning on snagging it complete for extras instead of piecemealing the engine out for what I need.

In reply to GIRTHQUAKE :

I would assume that it is.

If it's NOT, then it would have MASSIVELY thick bores.  Mmmm.... boost

GIRTHQUAKE said:

Question for you guys; is the 425 block any different from the 500 it's based on? Light googling says no, but I want to make sure because I'm planning on snagging it complete for extras instead of piecemealing the engine out for what I need.

It is vaguely the same architecture.  I think some things are common, like the 472's crank.

Heads interchange, but you have to be very cautious of water passages.  They are a wee bit different.  When putting 425 heads on a 472/500 for instance, the one water passage is very close to the fire ring on the 500 gasket.  You just have to be careful on the heads you have that the water holes weren't machined too close to the fire ring.

Timing covers are different.  Intakes are different (425 actually uses a single plane intake for some odd reason)  HEIs interchange.

Just looked it up... 472 and 425 use interchangeable (physically) cranks, but counterweights are different, so you cant mix and match without re-balancing.

wheels777 said:

Pete. (l33t FS) said:

In reply to GIRTHQUAKE :

I would assume that it is.

 

If it's NOT, then it would have MASSIVELY thick bores.  Mmmm.... boost

The 425 is a small bore thin casting block.  I did enough exploration on Cad engines years ago.  There is so much less metal in the 425 block that you can move it with far less effort. 

FWIW, If I were building one I would stay with a 472 and not the 500 for a variety of reasons.  Throw on a pair of turbos and have a ball.

While the 425 and 472 share the same stroke the 425 crank is lighter weight also.

500 and 472 both have the big bore (4.30) and get their displacement with either a 4.06 or 4.304 stroke.  425 drops the bore to 4.08 and keeps the 4.06 stroke.  368s from the 80s further drop the bore to 3.80 and still uses the 4.06 crank throw.