VC Commodore hillclimb car – Unique Cars mag staff cars

By: David Morley, Unique Cars magazine

Date: 01.01.2017

VC Commodore hillclimb car - now a bit lower and on stiffer suspension.

VC Commodore hillclimb car - horrible, nasty, goneski!

VC Commodore hillclimb car - half inch spacer is next, then the carby.

VC Commodore hillclimb car - clearance issue.

VC Commodore hillclimb car - simple but effective exhaust.

VC Commodore hillclimb car - manifold and carby now in.

VC Commodore hillclimb car - now a bit lower and on stiffer suspension.

VC Commodore hillclimb car - horrible, nasty, goneski!

VC Commodore hillclimb car - half inch spacer is next, then the carby.

VC Commodore hillclimb car - clearance issue.

VC Commodore hillclimb car - simple but effective exhaust.

VC Commodore hillclimb car - manifold and carby now in.

Morley’s Project Duckshit gets a manifold and a low carb diet

Morley's hillclimb car is taking shape.

When I was a kid, the world was right into modifying Holden six-cylinder engines. About the same time as I got a licence, 10-year-old, mighty HQs could be had for peanuts if you could hack drum brakes and a croaky old 202. Could I ever…

Anyway, the first thing to do was to bung on a Bosch GT-40 coil, swap the back muffler for a hot-dog and carpet it with offcuts from the local rug shop. If you had a bit more folding at hand, the next step was to fling the El Wheezo Stromberg single-throat carby and bolt on something more exotic. Unless you were going for a set of triples (which we never were) or you were lucky enough to find a HD/HR X2 manifold set-up at the tip (which we never did), there was only one carby to consider: the mighty 350 Holley. And, as far as I knew, nothing changed for the next four decades. The 350 Holley was the prince of carbs that suited the Holden 202 down to the ground.

So, when Project Duckcrap needed some more horsepower, I immediately thought headers and a 350 Holley. I was only half right.

For the extractors, I stuck with Aussie-made and talked to South-Australian-based Pacemaker Headers whose gear is entirely locally made. When you tear off the shipping plastic, you see a lovely, high-temp-coated set of pipes. After talking with them, I chose a set known as Tri-Ys that use the secondary pipes as ‘sequential collectors’, meaning the scavenging process now happens at two points on the header, not just one as with a six-into-one design.

A six-into-one would have been more appropriate if  I needed maximum top-end power for, say,  salt-lake racing.  But I’m not; I’m going hillclimbing where low-end and mid-range punch are more valuable. So Tri-Ys it was. The Pacemaker headers are a neat, snug fit with enough clearance to still be able to get at the starter motor and, crucially, they seem to tuck up nice and high under the floor. Which is nice, because I’ve torn headers off before today while getting race-cars off trailers. The only change I made was to flange the collector so I can easily change exhausts to meet varying track rules and noise-limits.

For now, the exhaust is just a straight-through piece of two-and-a-half inch pipe, exiting under the passenger’s sill. Crude, but effective.

So what about that 350 Holley then? Well, doing the smart thing for a change I talked to folks who might just know more about this than me (and trust me, the phone book is full of people who fit that description). Anyway, I eventually got hold of the blokes at Hume Performance in Sydney who really know the score on stuff like this, even if their bread and butter is in monster, competition-spec and street V8s with horsepower in multiples of a thousand. Anyway, their advice was to consider one of the new breed of Holleys, starting with a small-capacity four-barrel, like, say a Street Avenger 470cfm.

But hang on, if a 350cfm two-barrel has been the default setting since Noah bought his first HR, surely a 470cfm carb is going to be too big. No, said the Hume Performance fellas. See, the 470 Holley four-barrel uses vacuum secondaries. So, until your engine is pulling enough vacuum to open them, the secondaries stay shut. Which means for a lot of the time, you’re running only on the primaries which are actually smaller than 350cfm. So, in theory, while that’s happening, you should get better air-fuel mixing and a more complete burn which means more grunt. And on the straightaways where you’ll build up vacuum sufficiently, the secondaries will then open up and give you the top-end surge you need. Brilliant.

A few days later a big box of stuff arrived including a four-barrel manifold to suit my 12-port 202 head, a half-inch spacer for the carb, a high-volume Carter fuel pump, a pressure regulator, some brackets and filters and the 470cfm vac-sec Holley. Oh, and a dead-sexy, crinkle-black Edelbrock air-cleaner.

It all fitted up with no real problems although I did have to grind a smidgeon off one corner of the inlet manifold boss just to clear its opposite number on the headers. And next time, I’ll do a trial fit before I lather gasket-goo everywhere (including now, on my grinding wheel). With the hardware bolted up, I found a universal choke cable and mounted that on a little bracket near the trans tunnel and hooked it to the choke arm on the Holley. The Hume Performance folk had already told me that a VB or VC V8 Commodore throttle cable would do the trick, so I wrangled that up too.

And you know what? Even with all my oafishness (and the fact that I hadn’t connected the vacuum advance line from the dizzy to the carby), I hit that old 202 in the slats and it fired up. Hell, it even idled. Well, it did till I revved it and it swallowed the piece of duct tape I was using to blank off the vacuum port for the brake master cylinder. Regardless, it lives!

Of course, the question you’re all asking is:  Why not go for a triple-carb set-up? Sure, they look special when you open the lid, but there are a few problems with them. For a start, they’re expensive and the power gain they offer is right up at the top end where I’m not planning to spend a whole lot of time in a hillclimb. But mainly, over the years I’ve found triples to be a royal pain in the dot to get running right. And then, it seems, the next time you start her up, the carbs are all cattywumpus and need sorting again. And my plan is to go to a race-track or hillclimb circuit and race the car, not tune the bloody thing. We’ll see how that goes, I suppose. Stay tuned.

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