[ccrider]

I know there have been other posts on this issue but could someone explain the difference between the 396, 427, & 454 engines. Someone stated that 427 and 396 cranks are identical, and that 427 and 454 blocks are identical. Where does the 454 get the extra cubes?

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Thanks,
ccrider
Member #:267
ACES Member #:03379
66 Chevelle SS

 

[JWA]

The stroke is different between the 454 and 427.454=4.00, 427=3.76 Bore is the same @4.251. (396 bore is 4.094)You could use a 396 crank in a 454 block to create 427,they use the same rods but the 454 pistons won't work due to different position of the piston pin. Hope this helps.

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Jeff ACES#841 TCG#158
68 SS396(454)
68 L78 Project
87 MC SS



[This message has been edited by ACE841 (edited 10-11-99).]

 

[DZAUTO]

Also, there is the 402 which was introduced in 1970. It has had many labels: SS396, BB400, 402 and 400 with 4bl. It amounts to a 396 that has been bored .030, resulting in a 4.125 bore. I have never been able to learn if the 396 and 402 have the same water jacket core, which means the 402 would have thinner cyl walls, or if the 402 cyl walls are just as thick as a stock 396. The reason for this concern is that if a 402 has thicker walls than a 396, then it can be bored bigger. Thus an original, numbers matching 402, if bored .060 or .090 over and had a 454 crank stuck in it would only be .030-.060 short of a 454. This would allow someone with a fine, original 70 SS396 (402) to almost convert their number matching 402 to almost a 454.
Why do I get off on these tangents?

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Tom Parsons

 

[Mr. D]

there are also two "truck" block BB gms. The 366 and the 427 "tall" blocks. You see these often in old rider or u-haul type trucks. These motors share the stroke with the 396 and 427 short block motors but the deck is higher (can't remember exact dim.). Intakes will not interchange but many other parts will.
They can make great stroker motors.

 

[Len]

BIG BLOCK CHEVY DECK HEIGHT FACTS.

Deck height for NORMAL Big Block Passenger & light duty trucks 9.8"

Deck height for 366 & 427 TRUCK block 10.2"

Difference of .4".

If you don't know what you're looking at, (if the intake is OFF) you might end up with a TALL BLOCK.

If you ever see a TALL BLOCK intake you'll KNOW. They have a funky DUAL thermostat setup & housing with a single radiator hose connection.

A TALL BLOCK intake will NOT fit onto a normal deck block (unless some machining has be done to the intake).

A NORMAL BLOCK intake WILL fit a TALL BLOCK with spacers. Available from various aftermarket sources.. Weiand, and others.

[This message has been edited by Len (edited 10-12-99).]

 

[SSteve L]

Many 396/402 blocks into the early 70's can be bored to the 4.251" bore of a 454. Many machine shops can check the cylinder wall thickness before attempting to do this to reduce the riskof wrecking the block. Core shift could stop your efforts dead in their tracks. With the stock 396/402 crank and this bore you get a 427. Add a 454 crank (and flywheel and balancer) and get a 454.

 

[Mr. D]

It is my understanding that the crank will not clear the block and the block must be relieved to accomodate the 454 crank in a 396.

 

[RatPowr]

To use the 454 crank in a 396/402 sometimes the block must be clearanced, but not always. Check to be sure, and if your lucky, you wont have to.

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66 Big-Block Chevelle Houston, TX ACES#3321

 

[Mr. D]

Seems I have also heard that the 427 crank has the same stroke as the 396/402 but is counter weighted differently than the 396/402 crank even though they share the same stroke.

Someone know for sure???

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Mr. D
72 454 Elcamino
68 RS/SS camaro
73 RS/LT/Z28 camaro
99 Firebird TA WS-6 A4

[This message has been edited by Mr. D (edited 10-13-99).]

 

[LIGHTWAVE]

I just finished building the exact same engine. A 427 using a 454 block and my 396 crank. I was able to use the existing rods but the pistons had to be 427. I went a little extream but ended up with a fantastic engine. It has 9.3.1 compression with the total Edelbrock Preformer RPM kit. (Intake, Heads,Cam & Lifters, Carb., Water pump and Fuel Pump) What a combo. She's a screamer and does she sound good. Believe it or not my original 396 got about 8 miles to the gallon and the new engine gets about 13 on pump gas. Not to bad...

 

[Mr. D]

LIGHTWAVE
Sounds like a neat combo. what kind of car do you have it in??

 

[route66_chevelle]

"IM BACK"
ok here:

cubic displacement calculation:

bore X bore X stoke X .7854 X #of cylinders

basically the crank has longer throws on the 454and is externally ballanced

 

[joe58]

396 is 4 3/32 X 3 49/64 (BORE, STROKE)
402 IS 4 1/8 X 3 49/64
427 IS 4 1/4 X 3 49/64
454 IS 4 1/4 X 4
This may help clearify the engine size difference