Big Block V Small Block

[Russ]

I'm sure that this question has been asked before on the site. But I can'find anything directly linked. I am about to finalise the spec for my Dax chassis and need to give them an idea of which engine for the mountings. The question is I am trying to decide between a Small Block or Big Block Chevy. Cost is a factor but it's not the only decision criteria. Which would you prefer and why? (that should get the opinions flowing) Thanks in advance Guys....

[wilf]

There is no simple answer to this, it is a perennial discussion which flares up regularly on www.clubcobra.com as well as here.

Big block normally means higher weight where you don't want it, often brings cooling problems, but will "behave" in a substantially different way from a small block - sounds different, pulls different etc.
Unlike the USA, my belief is that big block knowledge is harder to come by here in the UK - small blocks have become almost the "norm".

If you want the pull (torque) of a big block (well, almost) with the weight of a small block, why not look at a stroker small block - the 383 has become almost common recently. And it's far more cost effective than going the big block route, plus the packaging into a cobra replica is easier.

Did you notice I managed not to mention the FORD word once?


Wilf

[russell_ram]

>Did you notice I managed not to mention the FORD word once?
>

Not to good at adding up wilf.

I can count to at least one.

Russ

[Russ]

Thanks Wilf. I think the idea of a stroked 383 is the best of both worlds(?).
I'll have a chat with Repower who I'm told are best for Dax (Chevy)engine's.

[griff]

Russ

If you speak to Dax you get different stories:

1) There old big block was like sh*t of a garden accessory.

2) SBC has better handling.

So what do you want? That is the question that most of us have asked before we ordered?

Bit controversial but unless you have ordered a GD…………Support please!!!!!

[wilf]

Russ - I am sure there are other Chevy engine suppliers you could talk with, not that I am pulling Repower down, they did my own engine. But in all honesty, I am not the best person to be giving out advice about Chevy lumps - I am, up front and in the open, a Ford man, and Russell I did get almost to the end before I mentioned it earlier, aren't you proud of me? Amazing what therapy can do for a person.

On strokers though - these engines seem to be becoming extremely popular, both in the US and here. I have to say I am very pleased with my own, it does pull well low down considering the cam/heads etc I have in it, but runs strongly all the way to 6000rpm. A good compromise. Actually, now that I think of it, the cam is not that extreme, just high lift. Anyway, makes no odds since you will want to spec your own engine how you wish. Just remember, if you do go for a stroker, you will need to ensure it can breath well - cam/heads/inlet/headers all need to allow for the extra capacity.

I hope some Chevy users will chip in with their engine builder recommendations so that you have a choice.

Wilf

[robert]

Well, my personal opinion is that you cannot go wrong with a short Yorkshireman who can talk the hind legs off a donkey. Kenny at EDA knows a thing or two about engines and will make an engine based on your horsepower needs. The engines will also be reliable, as we all want acheivable reliable power, and that is his forte. If the racing community uses him, not just the SRGTC but the ASCAR and a number of other US specific series, then he is good enough for anyone.

He is also very cost-effective. I ran the prices he charged me for my engine build through Summit and Jegs and they all came out right with the VAT and duty.

SBC or BBC is your decision, however, you can get the big numbers from a SBC with a lot less weight. A number of SBC I know if are running high 500s and there are a couple of 600+ as well, and that is reliable HP as well. Bigger is not always Better.

Usual caveats apply, personal blah blah blah

Best Regards

Robert
Forum Admin

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[Russ]

I was thinking SBC originally, at the end of the day I suppose it's personal choice, but handling is more of a priority for me. I will have a word with the other guys you mentioned on the engine.

Thanks again lads...

[robert]

>If you want the pull (torque) of a big block (well, almost) with the
>weight of a small block, why not look at a stroker small block - the
>383 has become almost common recently. And it's far more cost
>effective than going the big block route, plus the packaging into a
>cobra replica is easier.

Wilf

Interesting point you have made, but others might not be aware that you cannot actually measure horsepower. Horsepower is only a measurement taken from the torque an engine produces.

First of all, from a driver's perspective, torque, to use the vernacular, RULES . Any given car, in any given gear, will accelerate at a rate that *exactly* matches its torque curve (allowing for increased air and rolling resistance as speeds climb). Another way of saying this is that a car will accelerate hardest at its torque peak in any given gear, and will not accelerate as hard below that peak, or above it. Torque is the only thing that a driver feels, and horsepower is just sort of an esoteric measurement in that context. 300 foot pounds of torque will accelerate you just as hard at 2000 rpm as it would if you were making that torque at 4000 rpm in the same gear, yet, per the formula, the horsepower would be *double* at 4000 rpm. Therefore, horsepower isn't particularly meaningful from a driver's perspective, and the two numbers only get friendly at 5252 rpm, where horsepower and torque always come out the same.

In contrast to a torque curve (and the matching pushback into your seat), horsepower rises rapidly with rpm, especially when torque values are also climbing. Horsepower will continue to climb, however, until well past the torque peak, and will continue to rise as engine speed climbs, until the torque curve really begins to plummet, faster than engine rpm is rising. However, as I said, horsepower has nothing to do with what a driver *feels*.

The equation for calculating HP is torque*rpm divided by 5252.

Robert
Forum Admin

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[Kelvin]

Hi Russ

There is a bloke called smax who does drag racing, he imports a lot of yank stuff. I haven't bought from him but on the phone he seems to be straight forward and others on here have recommended him, his e-mail address is smax@smax.co.uk . He quoted me around £500 for a chevy g/box, bellhousing, clutch, and fly wheel. I know this is not what you are looking for but its just an example.

HTH

Kelvin