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att 308 guru's, im looking for how to make maximum torque from a holden 308

Howdy chaps.
Im planning my 308 rebuild for the 4x4sandman. My aim is to get maximum possible torque whilst retaining the 5ltr capacity. What im looking at so far are two possible options, but first, the rest of the drive line is;

33in tyres, 3.9 to 1 diff's, gq transfer case, 4l80e trans with a lower 1st and 2nd. probably a low-stall converter.

Most likley option: A pair of Yella Terra high port ali heads on my red 308 with a roller cam, roller rockers, and other quality stuff.

Second option: Big paw holden/chev block with all the above gear. I dunno how they go with their engine numbers and whatnot, im still looking into it.

Just looking for anyones thoughts on all this jazz.

Cheers

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i dont know why you want to keep the 5 litres - most people that do simply do so to save on the cost of a stroker and the related costs with buying and preparing the reciprocating parts. extra stroke is a cheap way to make torque. what you are suggesting requires a SERIOUS budget.

IMO maximum torque would come from forced induction.

if thats not on the cards, then good flowing heads with the smallest port volume possible to achieve the flow.

custom cam to suit which will probably be low-ish on duration but still have decent lift.

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I wouldn't bother with alloy blocks or heads, for less money put some VN heads and stroke it, 5 ltr is a little small for your running gear, I'd even go to a 383 for not much more $$$

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Thanks for the reply Ben.

My thoughts behind sticking with the 5 litre, or there abouts capacity, is to help with highway fuel economy and having a broarder torque range. Here is how I think it works, but please correct me if im wrong;
If I have a longer stroke my engine is going to have to draw in more fuel on each intake to keep the fuel mixture in the sweet area, more displacement = more air and fuel or she'll lean out, I know you cant just fill up the extra space with air.

As for my thoughts behind a broarder torque range with the shorter crank I look at it from the point of view, now dont laugh, of someone riding a 15 speed mountain bike, which I used to do alot when I was a kid. You select the biggest cog at the back (think stroker crank) and you pedal very fast and dont really go anywhere, even though you know you have the power in your legs you just cant pedal fast enough. Now select one of the middle cogs (think 308 crank) and now you can use the power in your legs to get some speed without having to pedal so fast. Then you can select the smallest cog and its really hard, and so on.

I've got pretty good performance out of my 308 in the 2.7t car in the past with stock heads and a crow torque cam, redline single plain manifold and a decent exhaust. I want to get this thing to breath properly, and then I want to be able to turn and burn 33's!
ps. budget is no worries.

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hmm.

You actually DO want torque in a 4WD rather than horsepower... All other bits being equal, a longer stroke will give you more torque at a given RPM than a shorter stroke... You can use the extra torque for extra performance or you can gear the vehicle up and gain economy/longer engine life as an engine is only good for so many revolutions or so much power being produced over its life...

Some more thought starters in a little thing I wrote here: http://holdenpaedia....

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Cheers...Dave

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Intersting read Dave. My aim is balls from the start up to 5000rpm. I'll let yas know what I come up with. It will also be my first proper worked motor so im pretty excited so see what I come up with.

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hmm.

You want a brock spec 308. As ol mate said, vn heads, ported, dual plane manifold and a descent cam to brocky hsv specs. They were designed to give max torque and hp in a useable engine without going roller everything etc. Dont forget the quaddie and elec dizzy.

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