Big Blocks: Fact or Fiction

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In Corvette Fever's December issue, on page 48 is an article about Big Blocks. Some interesting facts about Big Blocks:

Big Blocks weighs only 80 lbs more than the small block.

Rectangular-intake ports not always flow better than oval ports, depends on the cam used.

The 450 HP LS6 was not ever offered in the Corvette, it was a Chevelle offer only.

The weakest year for Big Blocks was 1974, but it still produced 310 gross HP.

The ZL1's came in only 2 Corvettes, but they came in 69 Camaros.

 

[67HEAVEN]

Big Blocks weighs only 80 lbs more than the small block.
False. More like 110-120 lbs. difference between a mid-60's-to-early-70's example of both. However, by using aluminum heads, intake and water pump and mini-starter on a big block, you can make them almost the same weight.

Rectangular-intake ports not always flow better than oval ports, depends on the cam used.
True.

The 450 HP LS6 was not ever offered in the Corvette, it was a Chevelle offer only.
False. 188 LS-6 Corvettes in 1971.

The weakest year for Big Blocks was 1974, but it still produced 310 gross HP.
True, if 270 Net = 310 Gross

The ZL1's came in only 2 Corvettes, but they came in 69 Camaros.
True.

 

[motorman]

BBC bare block alone weights about 80# more than SBC bare block and you have to add more weight for the the heads,crank etc. i would think 150 would be closer. the 454 450 HP engine was installed in 70 chevelles. the LS-7,454 460HP 12.5 :1 CR was never installed in any production car

 

[jim coulter]

The 188 LS6 corvettes were rated 425 h.p., so technically there wasn't any 450 hp LS6 corvettes. I have an article here somewhere that a guy restored an old chevelle and it had an LS6 engine, but it was rated at 450 h.p.(at least the sticker on the air cleaner lid stated that it was 450 hp) I believe its an old Hot Rod mag. Don't know what the difference in the two would be, except maybe the cam?

 

[Tom73]

Big Blocks weighs only 80 lbs more than the small block.

Maybe the bare block was 80 lbs difference. In '73 the big block 4-speed added 211 lbs over the base engine 4-speed.

tom...

 

[MaineShark]

Re: Re: Big Blocks: Fact or Fiction

Big Blocks weighs only 80 lbs more than the small block.
False. More like 110-120 lbs. difference between a mid-60's-to-early-70's example of both. However, by using aluminum heads, intake and water pump and mini-starter on a big block, you can make them almost the same weight.

Of course, if you do the same tricks for a small-block, so you can compare apples to apples, the weight difference re-appears

Joe

 

[67HEAVEN]

Re: Re: Re: Big Blocks: Fact or Fiction

Of course, if you do the same tricks for a small-block, so you can compare apples to apples, the weight difference re-appears

Joe

And so does that amazing torque-in-the-butt feel too.

 

[motorman]

the early 66 427 vettes were rated at 450 hp(i owned a brand new one in 66) but later the same engine was rated at 425 HP. the 70 chevelles 454s rated at 450 HP( i owned one of those brand new also). after 1970 there were no more GM cars with 11.1 comp ratio or higher.