Which one do they mean...BigBlock.....

[Luvlegs]

I've noticed a few posts in the past week or two that asked questions about terms that were used almost daily and someone finally asked for clarification.. (kinda hard to do, like asking for directions...)

So, as noone was scalded (that I know of), I'm throwing one out there that is driving me nuts.....

I'm putting a 73, 454 into a 72 C10 - a lot of sites selling parts (ESPECIALLY "hot rod" type engine parts) will say for example... "for 68-83 Big Block"...

Well, I don't like calling to get clarification on everything I want to get until I'm ready to order from someone so, here's my question...

Does "Big Block" include the 400, 402, 454, etc.. for ALL those years? So the same valve covers (for example) FIT ALL OF THEM????? (wish I knew how to make that question BOLD)

When I see "Small bock" I think 350, maybe 400 and anything smaller.

But there has to be differences no? at least in groups of years????

Sorry for the long post and what may seem like a newb type question

[70cst]

Luvlegs...
I'm going to take a stab and then see if my guess was correct.
I would answer that the BB would be a 396, 402, and on up. Ok you experts. Am I close to being correct?

[bobthecop]

Big block is just that a big block, usually 396, 402, 454, physically it is larger, small block, 283, 327, 350, 307, are physically smaller. 400 could be either the bore in a small block, or big block. Brackets are different, motor mounts are different, every thing is different. There are differences in years and BB parts will interchange depending on years and manufacture. just my opinion I could be wrong

[Luvlegs]

Keep it coming - I know there are differences but what's the deal on why they advertise a part as "for big block 68-83".... it's not like they are generic ads, they make "it" sound like it fits all of them. And, to keep this going, when someone on here is selling.. say... a pulley, and they say "big block" should it be assumed it's only for 67-72s???? Keep the clarifications coming!

[manimal]

The 396,402,427,454 are all std deck big blocks.The 366,427t,and I think the 502&572 are all tall deck big blocks. The small block has 4 valve cover bolts,the big block has I think 7. The exhaust on a small block has siamesed center exhaust ports, the big block are evenly spaced. Your 73 motor will accept all bolt on items as the other std deck big blocks.The pullies and brackets are different between the short w/p and the long w/p.

[Luvlegs]

I think this is great -

STD DECK - good term, good info... ok - let's throw this on top - are there cut off years for "all will fit"... say 65-72 and then 73 to umpty squat? and I assume (there's that word!) it's different from engine to engine... I know this might be getting old or stale but I bet there's a lot of chin rubbing going on.. maybe even some "hmmmm" and "ah hah"s...

Perhaps I'm going about it the wrong way - do most call to order parts and have the phone techs say "this will or won't fit"? shudder...

[Troy-Built]

All external parts are interchangable on the passenger car or pickup truck big blocks. The tall deck truck motors take different intake manifolds and headers sometimes due to the 10.2 versus 9.8 deck height. Big blocks came with oval intake port heads on low to medium performance applications and rectangular ports on high performance applications. Also there were closed combustion chamber heads on the 65 to some 70 passenger cars. Some were as small as 96cc's. On the trucks and most 70 and up passenger cars they had open chambers. Most opens are 118cc's like on your 454. There are other combustion sizes but these are the most common. Also in 65 and 66 the camshaft had a grooved rear journal for oiling and must use only that style cam for that block. They will not interchange. There is much more to add to this and I probably just made this worse.

[70cst]

This is why this board and others are great. There are a lot of guys with lots of knowledge and experience and are willing to share with those of us who want to learn and have questions to aks. THANKS!

[Troy-Built]

If you don't know already frame mounts for a big block are different than small block on 67-72 trucks. I also know that the 454 changed to roller cam and no fuel pump mount in the 90's I believe for fuel injection. It changed later than the small block but not sure when. Also the tall deck truck motors had 4 ring pistons steel cranks sodium filled valves and heavier rods than the low performance motors and smaller intake ports (peanut). Just some info on heavy duty parts that can usually be bought for cheap. You wouldn't want to use the pistons but the rods and crank come in handy. The 366 and 427 tall decks had the same crank but a different bore. The 396 is a 4.094 bore until mid 69 when it went to a 402 and got a factory .030 over bore to 4 1/8. The 427 and 454 passenger car and pickup truck block are the same for the most part. The 396 and 427 cranks are interchangable. The rods are the same length on the 396 thru 454 passenger motors.

[Troy-Built]

I almost forgot that the big blocks changed to a one piece rear main seal like the small blocks in the late 80's or early 90's. Someone else will have more info on that. One more thing 454's and 502's are externally balanced like a 400 all others are internally.

[Skip Greaney]

For our purposes "Small Blocks" came in 262, 265, 283, 302, 307, 327, 350, and 400 cubic inches with 2 piece rear mains, and are for the most part undistinguishable on the outside. Must use casting or engine ID to identify. "Big Blocks" came in 396, 402, 427, and 454 for 2 piece rear mains for passenger cars and light duty trucks. The medium duties also added the 366, and 427. Late model...(1986 and up) and performance engine include 502 and 572. Fuel injected engines include 4.8L, 5.3L, 6.0L small blocks, and 8.1L Big blocks

[Luvlegs]

ummmm.... ok.... whew! I'll have to print this out and take it to the reading room a few times so it'll sink in! Much appreciated info!

If the engine is from a 73 elky SS, is that considered a light duty truck?

I do believe I will have to call and let someone tell me what'll fit ....

If I see a canipulator module listed as "72 to 83 Big Block" (mines a 73) - do I go for it? (See what I'm getting at?) All Big blocks?

I just don't want to have to spend all day on the phone asking questions, getting prices and then have to do it again at the next place because of the way the parts are listed.

Thanks all - this is appreciated,.. overwhelming but much appreciated! (Good thing it's a hobby! hahahhahaah )

[70cst]

Gee with all this talk I just thought of something...The next time someone calls me a "Block" head, I am going to ask if they mean "Big or small " block? Get it?
I know...

[Luvlegs]

Originally Posted by 70cst

This is why this board and others are great. There are a lot of guys with lots of knowledge and experience and are willing to share with those of us who want to learn and have questions to aks. THANKS!

ehhhh.. YEP! I wish I was six so I didn't feel ridiculous asking the same thing over and over!

Can't say thanks enough alot of the time.

[Frizzle Fry]

You can verify parts compatability for most stuff at Summit's site -> http://www.summitracing.com/ Here's an example search for "air gap" for a 1973 chevy 454 -> http://store.summitracing.com/egnsea...=KeywordSearch

Then after you click on a specific part you also have this (see pic):

[manimal]

What is it EXACTLY that you are wanting to know? Bolt ons,internals,or what?
-Lance

[Troy-Built]

It's a shame you don't have the rest of the car. That is rare in 73. Is it a 73 motor? The easy way to tell is at the bellhousing area around the casting number area. There should be a letter for the month and the numbers for the day and year. If it is 73 and up pretty much anything external will work. You going to use a stick or automatic. Either way you need an externally balanced flywheel or flexplate.

[krue]

Remind me to move this to FAQ when everyone is done.

[manimal]

I believe that 73 was the last of the big block "CHEVELLES". That Elky would be worth some coin if you still had it. That engine should be a 2 bolt main with cast crank.The heads should be lrg oval port like 049's.They are probably the best type of heads for a street big block. Stock rockers are 1.73 ratio,stock rods are 6.135 long.High Perf rods have a dimple(hence the name "DIMPLE RODS") and 7/16 rods bolts,stock rods have no dimple and have 3/8 bolts. You can drop a 396,402,or427 crank into a 454 and make a 427-using 427 pistons.You can use closed chamber pistons with open chamber heads but not the other way around,dome will hit the heads.

[Luvlegs]

Sorry guys - home stuff came up - just moving in and momma.. I mean DUTY called...

Frizzle - PERFECT! I think I can use that for sure

Manimal - I have the lower end done and need to finish up the top - I took me about 10 times asking around to get the square v. oval ports straightened out! My buddy pulled the engine from the car about 4 years ago - it was in bad shape but moved under it's own power. I may have him see if he can still find it..

Troy-Built - I'm going to see if I can get some numbers off it today if anyone wants to do the researching part.. (hint, hint)

Krue - my mom would be proud of me...

I'm sticking with the auto - (400) that came from the same car. Here's what I have done so far:

'73 454 bored .030 over
Keith Black KB203 Hyperutectic Pistons with 12cc Dome
Comp Cams Valve Springs with new retainers
Heads were shaved just to true up and a valve job
Stock Crank turned .010
New cam bearings and freeze plugs
High volume oil pump
Mallory oil pump shaft
Hedman Ceramic coated headers
HEI

The TO DO is:

Timing Chain Set - Double Roller w/ Torrington Bearing Summit
Pushrods Chromemoly Summit
Roller Rocker Arms Crane
Magnun 286 Cam Comp Cams
Hi-Rev Lifters Comp Cams
Intake Manifold - Performer RPM Air Gap Edelbrock
Carburetor - 750 CFM Dual Line Double Pumper Holley
Valve Covers Edelbrock
Spark Plug Wires Mallory ??
Distributor Kit Pertronix

This is great all - again, much appreciated! Sorry again for the delay in getting back to this.

[Troy-Built]

Looks to me you already did the hard work. Just look for parts for a 73 454 and you will be ok. The type of rockers decides what valve covers to use also. Stamped steel roller tipped will clear stock height valve covers and the others won't. You can either use the Pertronics kit or buy a new HEI through Summit. Either way will be a good upgrade.