Coupethis

Well folks, the long wait is over. Your car is now well setup, is reasonably quick and responsive, but inside, the engine is stock as a rock! We can't have that

Ok, now here is where you will really need to decide what you want from your car. In other words, how fast do you really want to go? Do you want a 13 second true streeter? A 12 second street/strip car? An 11 second weekend warrior? Or 10 second strip animal? Bear in mind that going fast is directly proportional to how much money you'll need to spend.

The logical step here is that a 12 second car is what most people aim for. It's the kind of power that'll clean up most traffic light battles and will still be very streetable to drive around and cruise in comfort. Having said that, most of us just don't have the cash to walk into those times straight away, so there must be a compromise (read: a performance fix) in the meantime until we have enough funds to run 12's. The best way to compromise is to sort out the top end of your 308 and lay in wait of a 355 stroker bottom end.

True Streeter

Don't be fazed by all these 11 second street cars that supposedly dominate the roads, leaving all in their wake. Frankly, they are few and far between, and usually don't see many road miles at all. A 13 second car by today's standards is still pretty quick. Don't forget that all the latest stock SS's and XR6 Turbo's and whatnot are only running high 13's - HSV's are only marginally quicker.

Going for a heads/cam upgrade is an affordable way of chasing down those pesky SS's and all those mildly modified fart boxes while you save up for a 355ci stroker bottom end. Before I start, I must stress that I would only do a heads/cam upgrade if you are sure your 5 litre's bottom end is healthy enough to take the extra punishment of more power. I'd suggest doing a compression test to see how well the engine is holding compression - it's a good indicator of the condition of the bottom end. The last thing you want to do is spend money on performance mods and then can't afford to rebuild the engine when it goes pop.

What you'll need:

- Heads: I would start off with a set of L34's, B Cast heads or Red HQ heads if you can. If you dont have these heads you could still probably use the ones you've got, but I'd ask your head porter what they think is the right way to go here.

Have the heads reconditioned and ported with all the usual techniques, go for 1.94"/1.60" valves etc, but there's no need to have them completely hogged out. The idea here is to make the heads more efficient throughout the flow lift range, not a soggy head that only performs above 600 thou lift. Yes, VN Heads are definitely the way to go for outright power, but we'd have to change too much to what you already have for them to fit. Some nicely ported old style heads are more than enough to run a 12.

Also don't deck the heads too much, otherwise when you drop the stroker in you may run into compression problems - as in not being able to reach pump fuel friendly CR limits. This is also a reason not to go too big with camshaft choice as they usually need more compression to work.

- Camshaft: Choose something around a Crane 276 and a Crane 284. A camshaft around these specs will give a nice increase in performance without compromising driveability. They will also work well with a small high stall and moderate diff gears (refer to 308 Path To Power: The Basics Are Done, Where To Now?). Furthermore, when the stroker goes in, a simple cam/lifter swap to something bigger wont cost too much.

Crane Cams www.cranecams.com.au, COME Racing www.comeracing.com and Crow Cams www.crowcams.com.au are the most popular brands of camshafts and associated valvetrain components for the Holden engine. Although each have their own share of horror stories, these three are the most popular and for good reason. They also have complete camshaft kits that contain all you need for the cam swap if you decide to go that way.

- Lifters: (DONT reuse old lifters with a new cam). I'd go Anti Pump-Up lifters. While they are a bit noisier than standard type lifters, they are more reliable and accurate in the upper rpm brackets, as well as being more able to cop repeated punishment without going all soggy.

- Matching Valve Springs, Retainers & Pushrods: (NOTE I've heard Crow single springs are a bit suspect). Chevy LT1 type valve springs are meant to work well with these mild cams. I'd recommend Comp Cams for LT1 springs. Dual valve springs would be nice but require extra machine work to the heads in order for them to fit. In any case I don't think they're needed as yet. Some replacement hardened pushrods is piece of mind. No need to go chromoly at this stage.

- Timing Chain: A Rollmaster Timing Chain without doubt. The stock ones are weak as piss and stretch even in stock engines. Also, don't be tempted into getting a set of geardrives. IMO they have no place on a street car that sees regular street duties.

- Roller Rockers: First up, Yella Terra www.yellaterra.com.au are tried and proven, and are locally made. While not completely necessary, IMO roller rockers are a must for a performance engine. Standard pressed rockers just can't take the abuse of sustained high rpm. Furthermore, a set of bolt-on adjustable (don't bother with non-adjustables) Yella Terra's are pretty good for the price and suit this application perfectly. If you dont have the funds yet, you can get away with using the stock rockers in the meantime, then buy them when you do the stroker.

Alright, the heads and cam are done and you should be pushing out around 200kw's in this trim. In an early girl Commodore or Torana, with a 2800rpm stall and 3.55 gears, that equates to a comfortable 13 second pass. Not bad...just imagine what another 50-odd more cubes will do Till next time fellas...

evil_ss

a big thanx once again to jimmy for putting his time and effort into writing this article

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