Holden 202- straight 6 red

[Lurch202-6red]

What camshaft can I use to get more low and torque out of my 202 straight six red Natural aspirated holy carburettor it’s for a 1976 Toyota coaster that has had the H3 taken out and the 202 swap done thanks and cheers for any info

[zuffen]

Welcome to the Forum.

it strikes me it's a bit of a contradiction to look for more torque whilst running a Holley.

I'm guessing a Holley 350, although a 500 isn't out of the question.

Normally when chasing torque you opt for the highest airflow rate you can get, which usually means small ports and carburation.

When racing (many years ago) I ran a 500 on a 173 and it didn't start to go until around 2,500rpm.

Other's may be able to assist further but I would think the factory cam is about as tame as they come.

[Harv]

The Holley is not a bad carb for the red. Some guidance here:
https://www.fbekholden.com/forum/viewtopic.php?t=15098

If you cannot download the pdf from SCRIBD, shoot me a PM and I'll email it to you.

If I had a choice, a 390 4-barrel carb on a red motor is a neat trick.

At low throttle with the secondaries shut you are only running on the primaries. The primaries are smaller than the corresponding 2-barrel, so you get nice crisp throttle response (better than say a 350 cfm 2-barrel). Running vac secondaries is the key here - they stay shut until the engine needs the fuel. Mech secondaries will open up too early if you have a heavy right foot, giving too much venturi area and boggy response (i.e. a mech secondary 4-barrel would behave like a 2-barrel if the driver mooshed the go pedal).

Once those vac secondaries are open, you have a bloody big carb. The 4-barrel is measured at a different pressure (1.5"Hg) than the 2-barrel (3"Hg). If you convert the measurements, a 390 4-barrel will flow 550cfm (compared to a 350 CFM 2-barrel).

So all up the 390 gives you a smaller carb than the 350 2-barrel for quick takeoff, then slowly opens up to give bigger capacity than a 500 2-barrel once you are flying. Neat trick.

On the cam front, I'd give Clive Cams a call.
https://www.clivecams.com.au/

Cheers,
Harv

[Twin Spinner]

Never played around with the red six, but I once had a XY 250 2V GS 4 speed with a 4 BBL inlet and Holley 600 Vac Sec and headers, Down low and top end performance was unreal

[jeffa]

To illustrate what Harv said, a long time ago I had an XB GS 302. Exractors, exhaust and a vac sec holley 600/ 4bbl manifold.
Just as an exercise, I put a microswitch on the secondary linkage (at the butterfly), that lit a light on the dash.
Very handy, but it DID show how little the secondaries operated during most driving. The car was dynoed and the carb was correctly set up.

[XP6]

One of those commy V6 superchargers would give you plenty of torque from a carby 202