first off, they mad 350BB's right, and how much can they be bored to??? i know SB's can be 383's, how bout BB's???

also what would be better to rebuild, a chevy 350BB or a pontiac 400SB???

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Trent
---Car---
89 Firebird/305 L03 TBI A4/t-tops
Open Element Edelbrock Aircleaner w/ K&N air filter/Summit Chrome Valve Covers
Edelbrock TES headers 3" out/flowmaster American thunder 3" exaust/Catco cat
Edelbrock Performer manifold/small block 400 rebuild going in next summer
---Stero---
Pioneer DEH-P730 Premium
Infinity 2way 4652 4x6's/Pioneer 4way ts-a6985 6x9's
profile cl640 110x4

 

No such thing as a 350 big block. Chevy big blocks come in short-deck versions (car & light truck) of 396, 427, & 454; and tall-deck versions (big truck) in 366 and 427.

Small block Chevy motors come in 262.5, 265, 283, 302, 305, 307, 327, 350 and 400 from the factory; and a dizzying array of sizes that the rest of us have cooked up with either aftermarket parts or mix-and-match stock ones, like 377, 383, 334, 427, 434, 396, etc. The NASCAR guys run a 358 for instance, 4.155" bore (.030" over 400) with a 3.31" stroke (327 stroke, + .060").

No such thing as a small block or a big block Pontiac. All their motors have the same bore spacing, which is the criterion for whether a block is "big" or "small". IMHO (having built many a Pontiac motor over the years) they're all "big".

So your last question has no meaning. But to answer the question I think you are really asking, it makes more semse for most people to build Chevy motors to go in these cars, because they fit. Other motors including Pontiac need different transmissions, exhaust, accessory arrangements, etc.; which, judging by your question, you're probably not ready to deal with just yet.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited December 04, 2001).]

 

yea this kid has a pontiac 400 and a Chevy SB350, i want to rebuild an engine from the ground up, i will also be replacing the tranny and rear end, which would be better, obviously the 400 is bigger, but the 350 can be made to a 383, and i have noticed there are more chevy parts out there than there are pontiac, so which would be a better choice???

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Trent
---Car---
89 Firebird/305 L03 TBI A4/t-tops
Open Element Edelbrock Aircleaner w/ K&N air filter/Summit Chrome Valve Covers
Edelbrock TES headers 3" out/flowmaster American thunder 3" exaust/Catco cat
Edelbrock Performer manifold/small block 400 rebuild going in next summer
---Stero---
Pioneer DEH-P730 Premium
Infinity 2way 4652 4x6's/Pioneer 4way ts-a6985 6x9's
profile cl640 110x4

 

Depends on what you want to do with the car, if you are going to keep it forever, and how much you want to spend. If it was me in your situation, I would go with the Poncho 400. It's one of my favorite engines. It has tons of potential, makes lots of torque, and is very strong with stock parts. With a tranny replacement already needed, a th350/th400 with a BOP bolt pattern would work nice. Moderate axle ratio(like 3.23's) wouldn't be a problem with the torque output of the 400. After all that being said, you could probably build a chevy engine cheaper and make more power.

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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

im thinking that i will build an engine(spend about 4-5 grand), then take my 305 and find a fbody with a blown engine, drop it in, and use it for a daily driver, while keeping the 350/400 for racing and weekend car, im leaning twords the pontiac because its bigger, and i always wanted to put a pontiac engine in my pontiac, ill see if hell sell me it tomarrow

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Trent
---Car---
89 Firebird/305 L03 TBI A4/t-tops
Open Element Edelbrock Aircleaner w/ K&N air filter/Summit Chrome Valve Covers
Edelbrock TES headers 3" out/flowmaster American thunder 3" exaust/Catco cat
Edelbrock Performer manifold/small block 400 rebuild going in next summer
---Stero---
Pioneer DEH-P730 Premium
Infinity 2way 4652 4x6's/Pioneer 4way ts-a6985 6x9's
profile cl640 110x4

 

Although I never got into Pontiac or Buick engines you have to understand that displacement doesn't mean much. The whole design of the engine needs to be taken into effect.

The SBC engine although very popular, is a poor design above a 350 (383). The bore spacing is too narrow. The crank position is too high for proper long rods and the cam position is too low in relation to the crank. They also use small diameter lifters when compared to the other GM blocks. I don't even want to get into the SBC head and valve arangement designs.

When you look at how other engines are arranged you can see better or worse layouts of the components. Since everyone seemed to have built a 400 engine (not just GM engines) at one time that's a good size to use as comparisons. Even the BBC 396 +.030 was called a BBC 400 although it was really a 402.

The SBC 400 just happened to be the largest displacement GM was able to get out of the casting while still keeping the same external dimensions. They had to do a lot of changes to get that by using the shorter con rods and making the siamised cylinder walls.

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Follow my racing progress on Stephen's racing page
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87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

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Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
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87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

actually the 350 pontiac IS a big block, there scale was a bit diffrent (265-301 small block 326-455 big block) and that pontiac 400 is a big block also, i would forsure go with the 400 pontiac, those things are powerhouses and just as cheap if not cheaper to build than a 350 chevy.

 

Eh, all ya young'uns are forgettin' the 1958 348 cid Chevy. Step aside so I can put some learnin' on ya...

Same exterior size & shape as the immortal 409 (as in "dual-quad 4 speed positraction 409"). Originally intended to be a truck engine, put in passenger cars (but not Vettes) in an attempt to keep up with Ford and catch up to Olds. Available with single and dual quads.

Did I mention it was a dog? 100 lbs more than a SBC, block castings different between 348 & 409 so little interchanged. My '57 with 327 truck shortblock with 283-everything else, cast iron Powerglide, kept up with a '58 stripped down panelwagon w/dual quad 4 speed 348 back in '73 (I didn't know much in those days).

Did I mention it was a dog?

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

I've never heard of a 400BB, I think they were SB.


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2 Tickets to game= $250
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Sitting 20ft. from MJ= Priceless
'86 IROC T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
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im postive its a big block EVERY 400 GM made was a big block except the chevy 400's (olds pontiac and buick all have 400 big blocks)

 

My only concern is that if you are going to do the rebuild at home (I'm assuming you may not since you plan on spending 3000) that you could have problems with the 400. My reason for stating this is that the 350 is internally balanced while the 400 is an externally balanced engine. If the engine is balanced incorrectly you can have some serious problems. Super Chevy had their 400cid block that tore itself apart because when they balanced it one little tiny thing was done incorrectly...

-=-Mike

 

first of all, a 348 isn't a 350 so there isn't no learning there. there were two 400's advertised for chevy. the 400sbc and the 402 bbc. the 402 was advertised as a 400 initially but is really just a 402 bbc. all pontiacs from 326 to 455 as mentioned are big blocks (taller deck) and the 265 and 301 are small blocks (short deck). the 350 block can be taken to i believe it's 401 cubic inches without too much trouble. there is a recent article on it in hot rod or car craft, i forget which. it's simply a .060 overbore with 3.875 stroke.

 

Hey, a 348 is as close to a 350 as a 402 is to a 400. Besides, a SBC 350 is actually 349.8477 cid, anyway...

If you look carefully, you will see the SBC 400 referred to as a "2bbl 400" and the 402 as a "4bbl 400". They never really did call the 402 a 402 in any literature.

In fact, for the first year, they called the 402 a "396". It was a 4.125" bore vs. the 396's 4.094" bore (same 3.76" stroke).

Hey, that means a 348 is even closer to 350 than a 402 is to 396!

So there!

 

There is no such thing as a Pontiac "big block" or "small block". The 301 & 265 blocks are exactly the same bore spacing (the thing that determines the "size " of a block) but are "short deck" blocks. The Olds 307 (gag), 350 & 403 are like that too, with a short deck, but with the same bore spacing as a 400 or 455. In both cases, those mfrs introduced the lighter-weight short deck blocks late in the life cycle of their engine's existence, in an attempt to improve gas mileage by both lowering the CID and reducing weight, while maintaining the reliabity of their bottom end, for as close to zero development cost as possible. They were truly dinosaurs by the time they were finally discontinued.

The 400 motors in early 70s Chevys were either "400 2-barrel" which was a small block, or "400 4-barrel" which was the big block 402. They were also single and dual exhaust respectively which made the cars easy to spot at the time. The SBC 400 and BBC 402 are almost exactly the same CID, at 401.6.

five7 is right about the old 348/409 motor, it was not nearly what the song made it out to be. If you ever see one you'll know why; it's just all around an old-style small-port high-torque low-RPM tractor motor, nothing like a Mark IV BBC (the 396/427/454 etc. one). Its most unusual feature to the modern eye was that the head deck wasn't perpendicular to the stroke, so the bored part of the bore didn't come all the way to the deck. Weird.

But who cares about all that nostalgia. A Pontiac motor is heavier than a SBC, and not very much more powerful in general no matter what the displacement. A 71 Firebird with the SD455 was no faster than a 71 Z28 with the solid-cam 350, maybe not even as fast; and it was even more nose heavy than the Chevy, so the handling was absolutely awful. To get a Pontiac that runs better than a good 350 you have to go find rare old heads or buy new ones which cost far more than SBCs because the production volume is so low. If you were around when they were common and new, you would remember that a 74 Catalina with a 400 was just as dog slow as a 74 Impala with a 350. Same exact chassis, nearly the same weight (except for the heavier Pontiac engine), the 400 didn't outpower the 350 at all. So even though there are good Pontiac motors out there, every Pontiac motor isn't a good one, any more than every Chevy 350 is a gem. And good Pontiac motors are really rare nowadays, far rarer than good Chevy motors.

Somehow I doubt that some old motor some kid has laying around that he'll practically give you is going to turn out to be your dream platform for your ideal motor. More likely, if you go down that road you would end up spending an incredible amount of money to build the poorest handling 14 second car in town, just to be "different".

For my money, I'll stick with a SBC; I'll take the weight advantage, the transmission that already fits the car, exhaust systems that can be bought off the shelf, etc. etc. Dollar for dollar, I'll make a SBC go faster than I ever made a Pontiac go; and I've built some fairly stout Pontiacs, back when they were easier to find. My favorite of all the Pontiacs I've had was a 59 Catalina with a 389... for something that huge, it could really fly. But it wouldn't run with a modern muscle car, or even a third gen F car.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

in case you haven't learned when you were a kid two different size items make a big and small. tall deck is larger than a short deck, making it a larger block thus big block and small block. blocks such as small and big block are only determined by the manufacture. they are advertised that way. pontiac does not define them as small and big, although one block is larger than the other. close enough doesn't apply with cubic inches. within a half cubic inch, sure but we aren't calling 396's a 400, 283's a 285, 302's a 300, etc. 348 is a termed as w block, 349 never really had a name other than LT5, and 350 is just small block. all within a bit of each other, but none the same. 346 is not a 350 and it will never be. the thing with the superduty and LT1, not even close let alone there being no superduty 455 in 71. first year for that was 73 and even the h.o. 455 made in 1971 did beat the LT1 rather easily. there also was a 4 barrel version of the 400 sbc built.

 

Siamesed cylinder walls!? How does that work? Does anyone have a pic?

 

I have to agree with RB83L69 on this one. I'm a Pontiac guy and work on Firebirds/Trans Ams a lot. I hate it when people refer to the Pontiac motors as "big blocks" or "small blocks." They are all the same. If they could be classified as something, I guess they would be big block because they are heavy as hell.

Go for the 400 Pontiac in your car. That would be bad a$$! I want to build a 455 and put it in my 75 Firebird till my 92 needs a motor and then swap it in. Man, I love Poncho motors.

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1975 Firebird - Pontiac 350, TH350, 27k original miles, rustbucket, ongoing resto project

1992 Firebird - 305 TBI, 700R4, sport appearance package, t-tops, flaming red, 89k miles, Weiand 360 air cleaner assembly, CAT Power Engine Parts race underdrive pulleys, more to come....

 

Siamesed cylinder walls means the cylinders share the same wall. Normally there is a water jacket surounding the entire cylinder wall. On siamesed cylinder walls there is an area where the cylinders are joined together and no water jacket between them. They used steam holes into the head instead. This was the only way to increase the cylinder bore and still keep the same external dimentions. That's also why a SBC 400 block can only be safely bored out .030". The walls start getting thin after that. There are good aftermarket 400 blocks that have no problems such as the bowtie block. They just have better castings.

454 BBC also have siamesed cylinder walls but don't have the problems that the SBC 400 did.

 

Just to add some more familiar data into the big block vs. small block debate with something that perhaps you may be more familiar with since it's been used in late model vehicles. The windsor small block ford. The 302 / 5.0 in the mustang is a short deck engine. The 351 is a tall deck engine. They are externally visibly different for the deck heights, with the short deck engine having the intake nearly on the bellhousing mounting pads, vs raised for the tall deck.
For that matter, look at the cleveland small blocks. IIRC the bore spacing is the same, i recall big stroker windosr cranks based off 400M cranks. However xternally a cleveland looks like a big block. But it's called a small block.

Just cuz BOP engines are esoteric doesn't mean different rules apply.

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Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
305 TPI A4 2.73 - 14.7 @ 93.6
Stock except ported plenum and dual cats
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

BUYING CARS WITH ENGINES THAT DON'T RUN IS NOT A GOOD IDEA. I bought my IROC this was and because it was compely blown it would not crank(later found a jammed con rod)...anyway they kid claimed that the electricals and all that was working fine....I put the new 305 in and it has a FUBARed electrial stuff. Sensors where blown...rednecked connections(my cruise still won't work) It took me 3 months to get rid of a 36 and 34 and even then I had to take it somewhere.
Find a car with a engine with a really bad knock or smokeing etc etc.

[This message has been edited by camaro6spd (edited December 06, 2001).]

 

Boy what a bunch of crap in one post! Anyway rb83l69 I'd like to see a SD455 1971 firebird! If you want to race a 455HO 1971 firebird with a 350 Z28 you would get blown away! Trent257 the sb chevy will cost you less.

 

Gio, I was there when those cars were new, and that's not how I remember it. I remember them running about the same in the 1/8, if the Bird got traction, which they tended to have more trouble with, being even more nose-heavy than the Camaro and all; and then the Z28 just walking away past the 1000' mark. I don't have to read magazine articles to tell me romantic stories about how fast those old cars were, I was there. Were you? I'm really not interested in arguing about it, but it bothers me to see innaccurate non-information spread around. That's not what this BBS is for. Romantic nostalgia exaggeration and partisan white lies (the guy with a built one kind of car beating a stock some other kind of car, therefore the one kind must be the faster car for all time) doesn't belong here.

Another couple of big vs. small situations... the Chevy Mark IV Big Block comes in 2 flavors, conveniently known as short deck (came in cars and light trucks, 396/427/454) and tall deck (comes in heavier trucks like dump trucks and some school buses, 366/427). Same bore spacing. Not known as "big block" and "even bigger block". Also, Chrysler has the same kind of a deal, although they don't have the same sort of deck height variation; the 318/340/360/400 is a "small block", the 383/440 is a "big block". The F*rd FE block (considered the "big block" after the "small block" 260 came out, and up until the 429/460 was introduced) came in CID as small as 312 and as large as 428 that I can recall, where their small block comes in sizes up to 351 and the Cleveland design in up to a 400 (with the C4 bell housing, therefore known as "modified").

Ed is right, the Cleveland motor has the same bore spacing, and even the same coolant passages and head bolt pattern, as their Windsor small block. That's what a 302 Boss was: a Windsor small block with Cleveland heads on it. People still build those today; you just have to use a 289 intake to match the deck height, a 302 or 351 intake won't fit. And those flavors aren't called "small" and "even smaller" and "really really small" either. They're divided up by bore spacing.

Pontiac motors are all the same bore spacing, as are Olds motors, so there are no "big blocks" and "small blocks" among them, only "tall deck" and "short deck". Yes the block may be bigger or smaller in terms of pure casting mass; but as far as classification, it's a non-issue. They all use the the same cams, which is a pretty good indicator of being "the same motor" regardless of deck height, just like the Windsor or BBC examples.

So, back to the original question: there is no such thing a Chevy 350 big block, or a Pontiac "small block" at all. IMHO the Chevy motor is the better choice for a number of reasons, if it's going into one of these cars. That is not to say that the Chevy is necessarily a "better" motor, just a better choice for one of these cars. IMHO the Pontiac motor and Chevy motor have similar potential for power, but every single piece it takes to build a Pontiac motor costs more than the corresponding piece it takes to build a Chevy motor. Then on top of that, the money that it costs to futz around with adapting stuff to accomodate a non-original motor that really isn't any better than the original type, is money that can't be spent making the motor (or the rest of the car)better. Stick with a Chevy motor, you'll get a whole lot more bang for your buck in one of these cars.

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"So many Mustangs, so little time..."
ICON Motorsports

[This message has been edited by RB83L69 (edited December 08, 2001).]

 

All these "nicknames" like big block, small block etc evolved over time. In the beginning the heads (flat-head, hemi, cammer) were used to differentiate. Then as manufacturers produce large versions and small versions of their motors (for various marketing reasons) the term "small block and big block" came into the lexicon.

For Chevrolet that happened in 1958. Then around 1963 Cheverolet introduced the "mystery" 427 at Nascar when they unleased the initial "porcupine head" (since Chevy still had the 409 big block). I seldom hear that term (porcupine) any more because when people refer to BBC they immediately assume the current Mark IV.

Over time, bore spacing became the defining specification as to whether to catagorize a particular engine as a "big block" or "small block" (when a manufacturer only has 1 engine). No one in their right mind would consider the Cadillac motor from the late 60s/early 70s a "small block", even though they Caddy only has one engine.

Conversely, AMC couldn't really be considered a "big block" even though they had the single block from a 292 to 401. From a bore spacing perspective, they are more of a small block.

Pontiacs are funny. From a bore spacing they would be more of a "middle block" with a tall deck. There is no such term, so people kind of lump them as a "big block".

As to the 71 SD455 vs early 70s LT1 Z28. I have to agree with RB and say that I don't remember the SD 455s (all in bone stock condition) to being the clear winner. The SD 455s had a ton of torque and hooking them up was a big problem. If you could, the SD would jump out of the hole and it was a "catch up" game for the LT1. Quite similar to the TPI L98 vs Mustang; gotta get the L98 to hook and get across the finish line before the Mustang.

I say all this, much as RB...I (and all of my buddies) were driving those cars NEW in the early 70s when they were all basically stock. I drove Pontiacs in those days (along with a couple of AMCs). When it came to modifying our motors, I will say one thing, all the guys who had Chevys had a lot more parts available and at much cheaper prices. Pontiac no longer had their "SD factory parts" available over the counter like they did in the early 60s. It was actually a depressing time to be a Pontiac owner and very little available and what was available was expensive as hell.

It is one of the primary reasons I eventually switched to Chevys myself. I could build my 327 far cheaper and to be much faster than another buddy that had a 455, in those days. In fact, it is easier today to get aftermarket parts for Pontiacs than you could 25-30 years ago. As RB said, Pontiac guys had to find particular parts off particular years at wrecking yards and then work them and HOPE you could keep up to the Chevy guy who just picked up his aftermarket parts at the local speed shop.

As "manufacturers" own support for hot rodding engines, I really liked AMC. AMC had a lot of "factory hot rod parts" that you could readily order from any dealership.

One of the fastest cars I recall was a modified 69 390 AMX with "factory parts". He shocked many SD 455s and LT1s, and could brag that he was able to get all his parts "over the counter" at his local AMC dealer.

[This message has been edited by Glenn91L98GTA (edited December 08, 2001).]

 

I have the 402BB in my 71 Impala convertible. I can't imagine having any stock small block in this car. This thing is over 4000lbs and that "weak" 402 has the giddy up to move it out! I'd love to put the 402 into a lighter car and see what it would do. It's not much off the line due to the 2:73 rear, but it will murder the single spinning tire and once moving, she pulls hard all the way to a buck 20.
Big cars need big blocks!


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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!