Big block/small block?

Fox Body · 07-26-2002, 08:37 AM

Quick question:

Hey, I hesitate to ask this question b/c somehow I feel I should know the answer, but it is one which I simply have never thought about.

When do motors become big blocks? I'll assume it is from the amount of liters or cubic inches-- once it passes a certain #, it's a big block? (I feel dumb asking this, but anyway, here it is). What distinguishes a big block from a small block?

Eric4Nitrous · 07-26-2002, 11:52 AM

Good question..basically what diminishes a small block from a big block is the size of the heads, stroke, bore, etc.

The Deuce · 07-26-2002, 12:21 PM

I always thought it had to do with the type of block used, ie the way the oiling system is set up, etc. Hot Rod built a big block and small block 400 or 350, which led me to believe it wasn't a straight displacement thing.
I've also seen the 351 C referred to as a big block, because its a part of the 335 motor family.

Let's hope Chris can clear this one up for us.

Fox Body · 07-26-2002, 01:12 PM

the 351 modified 400 is still a small block isn't it?

blue00gt · 07-26-2002, 01:54 PM

Big blocks of a given brand always have a bigger bore than small blocks of the same brand. If you stroke a small block to 400+ CI, it's still a small block.

Rev · 07-26-2002, 02:11 PM

I think it depends on what the manufacturer was (is) producing at the time. The engines are distiguished as "small" or "large" blocks. It really doesn't depend on the exact displacement.

A "small block Ford" could be anything from a 221 CI Windsor to a 400 CI Cleveland. The big block FE was a 352, 390, 406, 427, or a 428 CI engine. The 385 family were all "big blocks". 429 and 460's. There are some larger 385 family crate engines.

Rev

PKRWUD · 07-26-2002, 03:23 PM

Displacement, bore, and stroke have nothing to do with it. Neither do the heads, or other bolt on parts. It is strictly the physical size of the bare block. Most manufacturers have 2 (sometimes more) sizes of V8 block castings, one smaller than the other. This is done so that the cooling jackets around the cylinders are never too far or too close, which would both lead to poor cooling.

For example, as mentioned, a Ford 352 is a big block, whereas a 400C is a small block. Set the two bare blocks next to each other, and you'll see that the 352 is physically bigger.

Take care,
~Chris

Fox Body · 07-26-2002, 04:54 PM

Ah ha!. The Wud of Pkr has spoken.

(this is what we were waiting for--according to the prophecy)

Thanks for illuminating our feeble minds PKRWUD.

srv1 · 07-26-2002, 08:30 PM

Chris is correct. it is psyical size. although one company of the V8's didnt have a "small" or "big" block and that was Pontiac. they all utilized the same block structure. Olds so called had a "small" and a "big" block, but mainly they just raised the deck height. the psyical size of a Olds 350 compared to a 455 Olds isnt that much different. just thought i would throw that in

PKRWUD · 07-26-2002, 11:46 PM

That's exactly right. The difference between an Olds big block and an Olds small block is 1" in deck height. As a result, parts like heads are interchangeable, but intakes aren't.

Take care,
~Chris

Rev · 07-27-2002, 12:03 PM

That's also why the Olds had little valves in the large displacement engines isn't it?

Rev

PKRWUD · 07-27-2002, 01:27 PM

They didn't all have little valves. The "B" heads came from the factory with 2.072" intakes and 1.625" exhausts. Starting in 1973, however, the combustion chambers got bigger, and the valves got smaller, for emissions reasons. Still, even then the 455's had 2.000" intakes and 1.625" exhausts. Not huge, but they flowed very well. They also could be custom ground to accept larger valves.

Take care,
~Chris

mustangman65_79 · 07-28-2002, 07:54 AM

One person told me that a way to tell the diff between a big and small, was the oil ports above the cam. Small block had small holes, and the big block had bigger-long holes.

07-26-2002, 08:37 AM	#1
Fox Body Mustang Maniac Join Date: Sep 2000 Location: GA, U.S.A Posts: 2,266	Big block/small block? Quick question: Hey, I hesitate to ask this question b/c somehow I feel I should know the answer, but it is one which I simply have never thought about. When do motors become big blocks? I'll assume it is from the amount of liters or cubic inches-- once it passes a certain #, it's a big block? (I feel dumb asking this, but anyway, here it is). What distinguishes a big block from a small block? __________________ 351W-powered 1979 Ford Mustang Ghia notchback '79 Video @ Idle Stock 5.8L under 4" cowl 'glass hood, C4 w/ Transgo shift kit, Holley 750 cfm, Edelbrock Performer RPM intake; Fluidyne Al radiator, Flexalite 175 electric fan, 1 5/8" MAC shorty headers, FRPP Al driveshaft; S&W 6-point cage; 2.5" Off road H-pipe, 2-chamber Flowmasters, 8.8" Rear w/ 3.55s; Weld wheels (15x6;15x8), Front: 225/60/15, Rear: 275/50/15 Nitto NT 555R Drag Radials; 14 x 4” K&N X-stream air filter. '92 GT (5-speed) Small In Car Video Stock 5.0L, 2-chamber Flowmasters, MAC CAI, Tri-Ax, Al pedals... "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

07-26-2002, 11:52 AM	#2
Eric4Nitrous Registered Member Join Date: Jan 2002 Location: Va Posts: 1,122	Good question..basically what diminishes a small block from a big block is the size of the heads, stroke, bore, etc. __________________ 68 Camaro Gene Fulton 632ci Two stages of Jug 8.41 164mph Rockingham 1-26-03

07-26-2002, 12:21 PM	#3
The Deuce Registered Member Join Date: Apr 2002 Location: Atlanta, GA Posts: 2,325	I always thought it had to do with the type of block used, ie the way the oiling system is set up, etc. Hot Rod built a big block and small block 400 or 350, which led me to believe it wasn't a straight displacement thing. I've also seen the 351 C referred to as a big block, because its a part of the 335 motor family. Let's hope Chris can clear this one up for us. __________________ 1997 Mustang GT "The Freak" - 13.80 @ 101.70, 2.07 60' 1995 Honda VFR750 - not much @ really fast (actual data pending.) 1964.5 Mustang 289 Rice Haters Club Member #13

07-26-2002, 01:12 PM	#4
Fox Body Mustang Maniac Join Date: Sep 2000 Location: GA, U.S.A Posts: 2,266	the 351 modified 400 is still a small block isn't it? __________________ 351W-powered 1979 Ford Mustang Ghia notchback '79 Video @ Idle Stock 5.8L under 4" cowl 'glass hood, C4 w/ Transgo shift kit, Holley 750 cfm, Edelbrock Performer RPM intake; Fluidyne Al radiator, Flexalite 175 electric fan, 1 5/8" MAC shorty headers, FRPP Al driveshaft; S&W 6-point cage; 2.5" Off road H-pipe, 2-chamber Flowmasters, 8.8" Rear w/ 3.55s; Weld wheels (15x6;15x8), Front: 225/60/15, Rear: 275/50/15 Nitto NT 555R Drag Radials; 14 x 4” K&N X-stream air filter. '92 GT (5-speed) Small In Car Video Stock 5.0L, 2-chamber Flowmasters, MAC CAI, Tri-Ax, Al pedals... "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

07-26-2002, 01:54 PM	#5
blue00gt Mustang Addict Join Date: Jan 2001 Location: McKinney, TX Posts: 1,294	Big blocks of a given brand always have a bigger bore than small blocks of the same brand. If you stroke a small block to 400+ CI, it's still a small block. __________________ Strike down the unroadworthy! 2000 GT Atl. Blue: '03 Cobra motor - 465rwhp/473rwtq, T-56 6-speed, full MM TA/PH & tubular K-member suspension, Saleen body, 17" Torq-Thrust II's, M/T ET Street radials, and lots more '94 Rio Red Cobra: All the bolt-ons, 3.73s

07-26-2002, 02:11 PM	#6
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	I think it depends on what the manufacturer was (is) producing at the time. The engines are distiguished as "small" or "large" blocks. It really doesn't depend on the exact displacement. A "small block Ford" could be anything from a 221 CI Windsor to a 400 CI Cleveland. The big block FE was a 352, 390, 406, 427, or a 428 CI engine. The 385 family were all "big blocks". 429 and 460's. There are some larger 385 family crate engines. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

07-26-2002, 03:23 PM	#7
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Displacement, bore, and stroke have nothing to do with it. Neither do the heads, or other bolt on parts. It is strictly the physical size of the bare block. Most manufacturers have 2 (sometimes more) sizes of V8 block castings, one smaller than the other. This is done so that the cooling jackets around the cylinders are never too far or too close, which would both lead to poor cooling. For example, as mentioned, a Ford 352 is a big block, whereas a 400C is a small block. Set the two bare blocks next to each other, and you'll see that the 352 is physically bigger. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-26-2002, 04:54 PM	#8
Fox Body Mustang Maniac Join Date: Sep 2000 Location: GA, U.S.A Posts: 2,266	Ah ha!. The Wud of Pkr has spoken. (this is what we were waiting for--according to the prophecy) Thanks for illuminating our feeble minds PKRWUD. __________________ 351W-powered 1979 Ford Mustang Ghia notchback '79 Video @ Idle Stock 5.8L under 4" cowl 'glass hood, C4 w/ Transgo shift kit, Holley 750 cfm, Edelbrock Performer RPM intake; Fluidyne Al radiator, Flexalite 175 electric fan, 1 5/8" MAC shorty headers, FRPP Al driveshaft; S&W 6-point cage; 2.5" Off road H-pipe, 2-chamber Flowmasters, 8.8" Rear w/ 3.55s; Weld wheels (15x6;15x8), Front: 225/60/15, Rear: 275/50/15 Nitto NT 555R Drag Radials; 14 x 4” K&N X-stream air filter. '92 GT (5-speed) Small In Car Video Stock 5.0L, 2-chamber Flowmasters, MAC CAI, Tri-Ax, Al pedals... "Red, thou art my companion. Hasten now your quickened metamorphosis to Green that I may conquer all who dare abide there beside me. May they be left thither behind burnt black." ---Fox Body

07-26-2002, 08:30 PM	#9
srv1 Get down..... Join Date: Apr 2001 Location: Room 103 Posts: 2,095	Chris is correct. it is psyical size. although one company of the V8's didnt have a "small" or "big" block and that was Pontiac. they all utilized the same block structure. Olds so called had a "small" and a "big" block, but mainly they just raised the deck height. the psyical size of a Olds 350 compared to a 455 Olds isnt that much different. just thought i would throw that in __________________ Cobra brakes are on! Finally..... ------------------------------------------------

07-26-2002, 11:46 PM	#10
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	That's exactly right. The difference between an Olds big block and an Olds small block is 1" in deck height. As a result, parts like heads are interchangeable, but intakes aren't. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-27-2002, 12:03 PM	#11
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Little valves? That's also why the Olds had little valves in the large displacement engines isn't it? Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe Last edited by Rev; 07-27-2002 at 12:16 PM..

07-27-2002, 01:27 PM	#12
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	They didn't all have little valves. The "B" heads came from the factory with 2.072" intakes and 1.625" exhausts. Starting in 1973, however, the combustion chambers got bigger, and the valves got smaller, for emissions reasons. Still, even then the 455's had 2.000" intakes and 1.625" exhausts. Not huge, but they flowed very well. They also could be custom ground to accept larger valves. Take care, ~Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-28-2002, 07:54 AM	#13
mustangman65_79 My poor 79 RIP Join Date: Oct 2001 Location: Suisun City, Posts: 2,320	One person told me that a way to tell the diff between a big and small, was the oil ports above the cam. Small block had small holes, and the big block had bigger-long holes. __________________ '84 mustang GT turbo '85 LTD '89 Camaro Irocz z28 '94 Lightning '96 Trans am

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