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  #76 (permalink)  
Old 02-10-2010, 10:26 AM
cobalt327's Avatar
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Quote:
Originally Posted by ap72
I ouldn't say the design was right at all.
You march to the beat of a Moog, not a drum.

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  #77 (permalink)  
Old 02-10-2010, 01:17 PM
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Welp, we have a nice snow day here and so had some time on my hands to poke around in this old thread. Nearly 8 years old! Wow. A lot of these older threads are great because they address some of the more basic questions of hotrodding like "big vs small block" "Ford vs Chevy" "Holley vs Edelbrock" etc.

Anyway its an interesting read. Not sure if its full of great information, but at least entertaining!

Back on page 2, and probably 7 years ago, somebody posted this:

Quote:
A good example would be to compare a big block and a small block engine with nearly the same horsepower and torque.

I did some calculations based on engine size, horsepower and cost of the engine by dividing the cost of the crate engine by the horsepower output. The results are interesting. This calculation gives you a cost per horsepower.

Chevy 502ci Ram Jet, 502hp/567ft-lb of tq cost $7095 = $14.13 per hp

Chevy ZZ 502ci base kit, 502hp/567ft-lb of tq cost $5850 = $11.65 per hp


Chevy 383 stroker, 325hp/415ft-lb of tq cost $3975 = 11.31 per hp

Chevy Ram Jet 350ci, 350hp/400ft-lb of tq cost $4525 = $12.93 per hp

Chevy 502ci, 338hp/512ft-lb of tq cost $5295 = $15.67 per hp

Chevy 350ci HO, 330hp/380ft-lb of tq cost $2495 = $7.56 per hp

The last crate motor listed as the Chevy 350ci HO is the best bang for the buck.
These are particularly bad data. This model only really works if cost per H.P. on any platform is linear, and its clearly not. Of course the lowest horsepower/torque motors have the highest ratio of horspower per dollar. By that end, you could rebuild a 90's 350 with all stock components for 1200 dollars and end up with 250 horse. What's that, 5 dollars per horse? Show me a 500-600 horse 350, then we'll look at comparable dollars per horse.

As you go upwards in torque and horsepower numbers, you need vastly more rigid parts, better engineered heads, forced induction or the like. With relatively stock, off-the-shelf components, obviously you can get into the 5 and 600 range with a big block more reliably and probably more cheaply than with a small block.

Although its not the target of this thread, it also overlooks the fact that there are a mountain of reasons to choose to build a smallblock or a bigblock rather than just dollars per horse.

Just a thought...

K
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  #78 (permalink)  
Old 02-11-2010, 08:06 AM
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I totally agree that $/HP is a poor comparison or yard stick.

It make more sense to use that type thing when comparing modifications or bolt-ons that are for increasing the power on an engine that's already together.

The car rags are great at doing a $150 mod (CC just did this very thing) to gain less than 1 HP.

They swapped carb bodies to make a 650 a 750, to gain something like .6 (as in 6/10) HP! It could have just as easily LOST .6 HP depending on the dyno, if they'd have made another pull...

Not a very good return on the money spent. But to hear them tell it, all was just dandy- ProForm being an advertiser and all.
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  #79 (permalink)  
Old 02-11-2010, 08:20 AM
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Quote:
Originally Posted by cobalt327
I totally agree that $/HP is a poor comparison or yard stick.

It make more sense to use that type thing when comparing modifications or bolt-ons that are for increasing the power on an engine that's already together.

The car rags are great at doing a $150 mod (CC just did this very thing) to gain less than 1 HP.

They swapped carb bodies to make a 650 a 750, to gain something like .6 (as in 6/10) HP! It could have just as easily LOST .6 HP depending on the dyno, if they'd have made another pull...

Not a very good return on the money spent. But to hear them tell it, all was just dandy- ProForm being an advertiser and all.
They wouldhave gained more power by putting that $150 towrds chrome goodies, a GM dress up kit is worth at least 30hp on some of those mag's dynos.
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Old 02-11-2010, 09:00 PM
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bugging me....

after reading the entire post.... i just had to make a post.

a few replies said that the added weight of a bbc wouldn't be worth it in a 3600lb car, and that a 383 could do better...

(just making up numbers, don't hit me)

489 bbc - 600hp, 550lb/ft (aluminum heads - 600lbs)
383sbc - 500hp, 400lb/ft (aluminum heads - 500lbs)

at the cost of 100 lbs, you are getting 20% more hp,, and 37.5% more tq


3600 + 500 = 4100lbs
3600 + 600 = 4200 lbs
weight difference = 2.4%!!!

so your saying that an added 2.4% in weight is not worth the extra 20% in hp??

do some math and figure that in mid to heavy car applications, a bbc is the OBVIOUS choice for getting it moving. just because the power to weight ratio of the motor alone is way off, doesn't mean anything for the whole combo.

My vote goes to BBC. that is why i am putting a bbc in my 3000lb car.

(but... if you are on a $2000 budget, then i guess you have no choice, or you REALLY care about gas mileage, than a bbc will be a bad choice. if you really want to go fast, BBC all the way!)
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Old 02-16-2010, 01:50 PM
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bbc vs sbc

Thought i'd throw in my 2 cents. I have a 3600 lb car. I'm am currently running a 383 stroker. Chassis dyno at 350 hp 345 lb/ft torque to the tires. It has 373 gears and a 2800 rpm stall. The car is quick, not a rocket ship but quick. Well I went out and bought a 468 BBC. I'm going to install it in a few weeks. Computer dyno software puts it at 550 hp 586 lb/ft of torque + or - 2% at the crank. Just numbers anyway. Nothing radical just a nice grocery getter. In my opinion torque rules on the street. People are right about the cost factor. I'll let you know how it turns out in a couple of weeks. Hopefuly I won't be disappointed.
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  #82 (permalink)  
Old 04-29-2010, 01:49 PM
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Big Block 454

What I would do is use the 454 BB and install higher compression pistons and Holley multipoint fuel injection with a tunnel ram or bug catcher its all up to you with 11.5 - 1 cr pistons and the tunnel ram fuel injection this motor depending on the stroke and heads you select could make any where from 600 to 900 horsepower
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  #83 (permalink)  
Old 05-03-2010, 04:36 PM
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Quote:
Originally Posted by Biscuit6447
after reading the entire post.... i just had to make a post.

a few replies said that the added weight of a bbc wouldn't be worth it in a 3600lb car, and that a 383 could do better...

(just making up numbers, don't hit me)

489 bbc - 600hp, 550lb/ft (aluminum heads - 600lbs)
383sbc - 500hp, 400lb/ft (aluminum heads - 500lbs)

at the cost of 100 lbs, you are getting 20% more hp,, and 37.5% more tq


3600 + 500 = 4100lbs
3600 + 600 = 4200 lbs
weight difference = 2.4%!!!

so your saying that an added 2.4% in weight is not worth the extra 20% in hp??

do some math and figure that in mid to heavy car applications, a bbc is the OBVIOUS choice for getting it moving. just because the power to weight ratio of the motor alone is way off, doesn't mean anything for the whole combo.

My vote goes to BBC. that is why i am putting a bbc in my 3000lb car.

(but... if you are on a $2000 budget, then i guess you have no choice, or you REALLY care about gas mileage, than a bbc will be a bad choice. if you really want to go fast, BBC all the way!)
I am new and replying to an old thread but I am glad I found this because I have been considering for a couple of years whether to swap my street/strip 350 sbc for a stroked 454 big block! This thread has shown me the light! My 1990 Corvette will soon be having a Big block sat in it and I don't care how long it takes or how much I have to modify the hood and I do not care about extra weight of a Big block because if I do worry about the extra weight of a Big block then theres no point me having an extra passenger as they will just weigh as the differnce or more

Last edited by (vette)mech; 05-05-2010 at 11:31 AM. Reason: missing word
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