[rel3rd]

My 454 to 496 build turned to crap, so I ended up selling the block, with hopes of buying a built shortblock from one of the vendors here.

BUT...

I have found a 4 bolt main, 427 shortblock with forged rotating assembly, ready to go, for $1500. I already have a 402/396 in my car, (and all the bolt ons and internals from the 454) so most if not all the incidentals and bolt ons are a non-issue. He claims with a .039" head gasket and 121cc heads, it would be an 11:1 compression engine, which I believe is maybe a little too high for a heavy cruiser, so I have to work around that, probably with thicker head gaskets....and/or pop those peanut port heads on.

Anyway, my question...

I KNOW EVERYONE on this site pushes 454's and bigger.....

I really didn't see much mention of 427's, I assume due to them not being as plentiful, but is this a shortblock worth getting??

 

[jeff swisher]

I built a buddy a 396 a few years ago for his 3/4 ton long bed 1969 chevy truck
456 gears 3000 stall
The engine has a tick over 11:1 with the 280H comp magnum grind.
Strip dominator.. and 800cfm carb.
Runs great no issues with 91 octane...
I ported the factory 69 large oval heads added 2.19-1.88 valves and polished the chambers..
all sharp edges were blended smooth ...
210psi cranking pressure...
I would bet your car is much lighter than this truck..that is used as a truck.

Attention to detail and 11:1 is a cake walk.

 

[rel3rd]

That's good to know. I guess the biggest concern I have is what appears to be near zero support for the 427's anywhere. Everywhere I look it's 454 or nothing, as far as parts, and combo suggestions go. I'm not familiar with them at all either. No idea what does or doesn't interchange (internally) with a 454 or a 396. I don't even know what the bore size is...lol.

 

[jeff swisher]

the 427 is a 454" bore with a 396 crankshaft basically
So if you bore your 396 out to 4.250" you will have a 427"
pistons are different between them all
rods are the same..
The 396 and 427 use the same balancers and flywheels
the 454 is externally balanced..so a different balancer and flywheel/ flexplate is used..
rods are the same..
heads interchange as do pans etc..
intakes are the same .. unless you get a tall deck block
same goes for distributors..

I really like the 427"
those big cube BBC's are TQ monsters and will break parts easier than a 396-427
But i do like to spin my short stroke BBC's..7000 rpm for a good cruiser street car.
take them to 8000+ for a drag race deal..

 

[rel3rd]

Awesome info Jeff! Thanks for sharing. Being that I have all the old 454 and present 396/402 internals, balancers, etc. It looks like I am covered there. I have 241 oval heads on the car now so they'd fit the plan as well.

Out of curiosity, do you have a cam choice or suggestion for an 11.1 439ci bbc with big valved oval heads, 2500 stall and 373's in a weekend toy with air conditioning? Lol

I'd more than likely want to go roller but a flat tappet isnt out of the question. I have solid ft cam now

 

[jfkheat]

Actually, quite a few guys here are running 427s, including me. If the short block you are looking at is a true 4 bolt 427 block it is a steal at $1500. If it is a 454 block it still a decent deal. As mentioned earlier, your 454 balancer and flywheel won't work with the 427.
James

 

[jackie schmidt]

For a small cubic inch engine to make the same power and torque as a big cubic inch engine, you have to figure out a way to move the same amount of air-fuel mixture in the same period of time. That means more RPM.
There are drawbacks to 7000 RPM on the street. Belts tend to fly off, every part in the engine from the valve springs to the rod bolts are stressed more, not to mention that to a achieve your goal, you have to stack more compression and more cam in it to achieve the RPM.
That is why, as you say, everybody says build as big of a engine as your budget will allow.

There is a little bit more difference in a bored out 396 block and a true 427 block. You will have thinner cylinder walls, some simply do not make it. I have done it once, but it was with a very early run 4 bolt 396 block, one that still had the tall distributor support and grooved cam bearing. It worked, (race boat in the '70's), but I have seen others try it, only to have cracked cylinders.
A true 454 block will have the notches for rod bolt clearance at the bottom of the cylinders, but side from that, utility wise, there isn't much difference in a true 427 block and a 454.
You can build a 427 with any 454 block, just stick the correct 3.76 crank, and the correct pistons in and that's it, with the non weighted balancer and flywheel.

Also, as for balancing. Not all 3.76 cranks are balanced the same. The ones that came in engines that featured the 7/16 rod bolts are counterweighted different. But that can be addressed when you do the build.

I would think that a 427 short block for 1500 is a great deal, if you want a 427. But keep in mind, to allow it to make the same torque and HP as a 454 or larger engine, everything has to be made more radical.

11 to 1 in a heavy cruiser? Sure, you can do it. That is, until you get caught in traffic on a hot day, or get some gas that is a tad low on octane, or, well, the list goes on.
Personally, for a real street car, I think 10 to 1 is a much more practical consideration.

 

[artmalibu]

What are your performance goals? Its only a good deal if you are happy when its done.

 

[Bluegoose1970]

What is the block numbers?


Sent from AutoGuide.com Free App

 

[VinceS427bb]

i've had a few 427's and enjoy them
buddies car has a 427 with the compcam 280H grind, 3"pipes, sounds/runs great [streetcar]

 

[gman628]

Being that I have all the old 454 and present 396/402 internals, balancers, etc. It looks like I am covered there.

My car has a 427 in it as well, and I'm perfectly happy with it, but curious why you wouldn't use the 454 crank from the previous build if you have it. If I were going to rebuild the motor I have in my car, and I had all the 454 internals, I know which route I would go :yes:

 

[rel3rd]

For a small cubic inch engine to make the same power and torque as a big cubic inch engine, you have to figure out a way to move the same amount of air-fuel mixture in the same period of time. That means more RPM.
There are drawbacks to 7000 RPM on the street. Belts tend to fly off, every part in the engine from the valve springs to the rod bolts are stressed more, not to mention that to a achieve your goal, you have to stack more compression and more cam in it to achieve the RPM.
That is why, as you say, everybody says build as big of a engine as your budget will allow.

I would think that a 427 short block for 1500 is a great deal, if you want a 427. But keep in mind, to allow it to make the same torque and HP as a 454 or larger engine, everything has to be made more radical.

11 to 1 in a heavy cruiser? Sure, you can do it. That is, until you get caught in traffic on a hot day, or get some gas that is a tad low on octane, or, well, the list goes on.
Personally, for a real street car, I think 10 to 1 is a much more practical consideration.

I'd be happy with a self imposed 6000-6500 rpm limit. I'm not really wanting to spin any (big or small) engine up to 7000, so I would have to depend on maximizing the 427 (as-is) by using a nice custom roller cam and some basic cylinder head mods. I'm not really worried about a dragstrip warrior, or an impressive dyno sheet either. Just found, what looks like, a good deal for a ready to run shortblock with all forged internals. I agree that I'd like to see a lower compression ratio, but am undecided on how to go about that at the moment.

I wasn't really set on any engine size, although I originally started the process of a 454 to 496 build and before any actual work was done, the price skyrocketed well above what I wanted to spend for a "toy".

Near me, a bare 454 block goes for $500 all day long, and just a 496 rotating assembly (again, near me locally) goes for $1600+, and that's without assembly or any machine work whatsoever...in fact that's what I sold my bare block for, so I thought $1500 for an assembled & ready to run shortblock was a pretty good find.

What are your performance goals? Its only a good deal if you are happy when its done.

Just want it to easily outrun/outperform my mild 402...that's pretty much it. "May" see the dragstrip once or twice a year, but hasn't yet, so it may never happen. I have also considered a small $400 adjustable nitrous kit for that 427 to 454 equalizer....

What is the block numbers?

Waiting to hear back with those.

Actually, quite a few guys here are running 427s, including me. If the short block you are looking at is a true 4 bolt 427 block it is a steal at $1500. If it is a 454 block it still a decent deal. As mentioned earlier, your 454 balancer and flywheel won't work with the 427.
James

Thanks James. I was just saying that I still have all the 454 guts and bolt-ons, if I ever chose to go that route in the future.

i've had a few 427's and enjoy them
buddies car has a 427 with the compcam 280H grind, 3"pipes, sounds/runs great [streetcar]

That's what I want....a strong running street car that sounds and runs good.

Thanks for the replies so far. :beers:

 

[rel3rd]

My car has a 427 in it as well, and I'm perfectly happy with it, but curious why you wouldn't use the 454 crank from the previous build if you have it. If I were going to rebuild the motor I have in my car, and I had all the 454 internals, I know which route I would go :yes:

That's just it though, sorry I guess I really didn't clarify....

I am not going to be rebuilding anything.

This is supposedly a ready to run 427 shortblock. The "plan" is to have my stock 241 heads re-done with bigger valves and a homemade port cleanup (which I've done to several heads and intakes over the years), add a nice camshaft (probably a Chris Straub custom roller), and wait and see if I need a looser converter, and/or a gear change.

After being laid off for 11 and a half months, and literally robbed of about $40K worth of lost vacation time and severance pay, I really can't (yet) justify buying the best of the best parts to build a nice 454, or 496, so I have been checking all over locally for a "deal", which I hope to have found. Realistically, I can't even justify buying a ready to run shortblock for a deal, lol...

If/when it gets tired, I'll probably still have the 454 parts.

 

[71350SS]

the 427 is a 454" bore with a 396 crankshaft basically
So if you bore your 396 out to 4.250" you will have a 427"
pistons are different between them all
rods are the same..
The 396 and 427 use the same balancers and flywheels
the 454 is externally balanced..so a different balancer and flywheel/ flexplate is used..
rods are the same..
heads interchange as do pans etc..
intakes are the same .. unless you get a tall deck block
same goes for distributors..

I really like the 427"
those big cube BBC's are TQ monsters and will break parts easier than a 396-427
But i do like to spin my short stroke BBC's..7000 rpm for a good cruiser street car.
take them to 8000+ for a drag race deal..

So if the 427 bore is the same as a 454 couldn't you add a 454 crank to 427 bore and come away with a 454 or a 30 over rebalanced 460 ?

 

[jackie schmidt]

So if the 427 bore is the same as a 454 couldn't you add a 454 crank to 427 bore and come away with a 454 or a 30 over rebalanced 460 ?

It will also take pistons, and a new balancer and flex plate-flywheel.

 

[rel3rd]

What is the block numbers?

Here is the reply I just got back....

The block casting # is 3999289. It started life as a 454 from a 1972 corvette. It was then bored for the oversized pistons (.060" over) and fitted with a GM forged 427 crank and 7/16" dimple rods. Rod bolts were replaced with ARP fasteners.

So, I guess it could always be turned into a 468 (or more) at some point. As I have said above, I have flexplates and balancers for either combo.

 

[71350SS]

It will also take pistons, and a new balancer and flex plate-flywheel.

but it can be done with the right parts selection ? Would balancing the assembly be a problem ? or is it do-able.
What about connecting rods, are they the same length ?

 

[rel3rd]

but it can be done with the right parts selection ? Would balancing the assembly be a problem ? or is it do-able.
What about connecting rods, are they the same length ?

I would say it's just a parts swap to make it work...since it is now known that the "427" I want to buy, was originally a 454...

I believe rods are the same length no matter what...unless it's a "stroker" motor.

 

[B433]

Bob, The 427 is a nice motor, I have run one since the late 80`s its been reliable as a anvil. Mine is also a destoked 454 with 9to1 comp large closed chamber 215 heads and a solid roller, you really dont need a bigger motor to run good on the street. That short block with the right cam will work good so I say go for it!


Brian

 

[Qwiktripz1320]

I'll throw my $.02 in here. The short block you are looking at seems like a great deal. Being an "engine guy", I could never run something like that as is without disassembling and checking everything myself. Besides that, if you are just looking for a step up from you current setup, it will serve its purpose well. I run what you might call a "Max Effort" 427, and it is pretty rowdy. Streetability is not great. Cubes make a huge difference, especially if you use similar components. The only reason I run the current combo is I got some great deals to replace the old defunct 468. The 427 runs quite a bit quicker/faster, but uses race fuel instead of pump, eats valve springs in far less run time, etc. As you already mentioned, nitrous oxide can make up for cubes, and is the cheapest power adder of all. I'd say go for it, but my advice would be to take it apart and take some measurements, or take it to somebody who can. You will sleep better at night.