New Big Paw Alloy Engine Block from Torque-Power

It all started 8 years ago when Torque Power made a goal to redesign and improve the Australian GMH 308 engine block and engine. Now the “ultimate” engine block for the popular 308 is here. It’s made of tough 356-T6 aluminium alloy, and the new design also gives consideration for cost effectiveness on parts to be used in assembly to achieve the full 500 cubic inch displacement and keep its overall small block size configuration.

  The block has been designed with a priority main oil system, so the oil feeds to the main and big end bearings first and the top second. All main caps are 4 bolt and billet steel, plus 195,000 PSI A1 main studs. And when it comes to displacement there is no bigger than the BigPaw, as it can accommodate a 4.500" stroke crank. Combine this with a bore of up to 4.200" and you get a 500 c.i.d. monster and only 3/4 of an inch (20mm)wider than the original 308 engine.
BigPaw blocks have six head studs per cylinder for high combustion pressures (superchargers, nitrous or turbo). Torque Power's new TP230cc & TP260cc CNC ported heads can accommodate the extra head studs and the larger cubic inch combos that need more intake runner volume and cfm flow. The extra two head studs per cylinder also help to stop “ballooning” effect of the cylinder sleeves when cylinder heads are assembled and engine running pressures are applied. The BigPaw is supplied with Darton .100" dry sleeves backed by .290" aluminium cylinder wall. That’s almost 4 times the thickness of the bore in the 308 Holden block.
BigPaw blocks will accommodate a wide range of Holden and some small block Chevrolet components. They’re available in only 9.500" deck heights. Torque Power tested the first BigPaw 460 cub displacement engine with a 4.250 stroke and 4.155 bore, with around a 266 degree at .050 solid roller cam, cnc ported TP230cc heads with 2.150 intake and 1.625 ex valves, with an intake flow potential of 700 hp, and the new bigpaw single and hi-rise dual plane intake manifolds. Check out the website for the Dyno results!
There is lots more to know about the BigPaw (offset push rods, ignition, crankshafts ,front covers, roller cam bearings and so on), so check out the magazine stories on the Torque Power website. Part 3 shows the dummy assembly of the big paw 460 cub in depth. Also take a bit of time to view our other products that we have designed and manufactured over the last 17 years to keep our great Holden engine alive; and now more superior than ever with cubic inch combinations and unlimited choice in components that the BigPaw can offer.

Torque-Power 434-464 Manifold

Click the link below to see all the BIG PAW Specifications