Weiand 177 Mini Blower
Would you pay $1,660 for an extra 112 hp and 101 lb-ft? That's the difference in Summit Racing prices between the $1,819 blower kit we used and the cheap $159.95 intake manifold it replaced. Since the mini blower only uses one carb, which you'd need for a naturally aspirated engine anyway, there shouldn't be any other expense to adding a mini blower other than perhaps a cowl-induction hood for clearance and maybe some fiddling with the throttle and trans cables. With just 3 psi boost, our 489 made peaks of 661 hp at 6,000 rpm and 698 lb-ft at 4,000 rpm.
Weiand offers two basic mini-blower kits for big Chevys: the Teflon-striped, 174ci former-B&M design that's 2 inches lower overall than the 177ci no-Teflon, Weiand-design unit. Both are available satin or polished, for either long or short water pumps; the 174 uses a 10-rib drive belt, and the 177 has a 6-rib belt. We used the cheapest kit, the satin 177ci model for long water pumps, PN 6521-1. Anyone with the skills to swap an intake manifold can install the blower.
The only drawback is that this blower, while conveniently small, is also a bit undersized for the displacement of a stroked big-block. The out-of-the-box pulleys only made 2 psi boost, gaining 82 hp and 70 lb-ft over zero boost. We ordered a 2.85-inch blower pulley (PN 6790, $71) and used it with the stock 6.00-inch crank pulley to make 3 psi at peak. We later tried a 7.00-inch crank pulley for a blower-drive ratio of 2.46:1 and made a peak of 5 psi, good for 749 lb-ft and 700 hp, but the blower had its tongue hanging out. The belt was starting to slip and the case was getting very hot, causing extreme power dropoff in back-to-back pulls.
So 3 psi was about the limit of the blower on this engine. Not that we're complaining about a simple 660 hp and nearly 700 lb-ft.
Weiand 8-71 Blower
For bigger power and shock value, we bypassed the Weiand 6-71 kit (PN 7483, 11/42-inch-pitch belt, satin finish) that is $2,139 at Summit Racing and went with the larger 8-71 blower kit (PN 7186, satin) Summit sells for $2,589. That's just $320 more than the price of the 177 mini blower kit, but you also need to buy one extra carb-ours was a 750 HP Holley supercharger cab, PN 80576S for $709.95-and a carb linkage kit, PN 7166 for $145.95. Throw in a couple of pulleys for tuning purposes-they run between $100 and $135, depending on size-and you've got a significant investment. Our kit, carbs, linkage, and pulleys added up to $4,390.85. You could knock that down significantly by using regular 750 double-pumpers (PN 0-4779C) rather than the HP-series supercharger carbs; the price would drop by $626 in carbs alone. However, we will say that this is the third big-block we've tested with the blower carbs, and they usually bolt right on with a near-perfect tune-up, so you don't have to mess with them. They also have boost-referenced power valves that can help with street driving.
Our Milodon pan needed just...
Our Milodon pan needed just a few slight dings to clear the extra 11/44 inch of stroke. The bottoms of the cylinders also needed a bit of clearance grinding.