The HP 290/350 is GM Performance Parts' value leading crate engine, with 290 horsepower

@ 5100 RPM,and 326 lb-ft of torque @ 3750 RPM on 87 octane fuel.The HP 290 horsepower

will provide great long term durability with its 4-bolt mains, PM steel rods, strong cast

aluminum pistons. The camshaft has .450" intake and .460" exhaust lift with hydraulic flat

tappets. The cast iron cylinder heads have 1.94" intake and 1.50"exhaust valves with 76 cc

combustion chamber. The heads have the conventional 12 bolt intake manifold attaching

design used from 1955 through late 1980. This engine was designed to work with the following

components: intake manifold 10185063, HEI distributor 93440806, balancer 6272221 (not

currently available with GM, please email customer service for availability), flex plate 471529,

you will also need a small block starter, water pump and fuel pump.This 350 engine is not

intended for marine use, and should be used in 1979 or earlier pre-emissions street vehicles

or any off road usage.Technical Notes: GM Crate Engines are horsepower rated to SAE Standards.

This engine is not intended for vehicles with fuel injection. This engine is designed for

carburated applications prior to 1985.

There comes a time when you may not just want more power, you may need more power. Times

like when you are towing your show car or bass boat with that 1970s-and-earlier GM truck, and it

just doesn't have the low-end grunt that you need to flatten hills or make a safe pass. For those

times, our engineers designed the HT (high torque) 383 with lots of cubic inches and other

components to enhance the low-rpm power that you need. The GM Performance Parts HT383

has been specifically engineered for low-rpm torque, and it's packed with durable parts that are all

brand new. It produces 435 lb.-ft. of torque at 4000 rpm, but more importantly, it produces more

than 400 lb.-ft. of weight-moving torque from 2500 rpm all the way up to its 4000 rpm peak. In

other words, your trailer's worth of weekend fun is barely noticeable when hooked to a vehicle

equipped with the HT383. The bottom end has a 383 stroker forged steel crankshaft, heavy-duty

rods, and hypereutectic pistons. The block is cast iron with 4-bolt main caps, and's up to the task

of making lots of power for years to come. Once installed, the HT383 makes it possible to look

forward to that big hill or long haul. Don't just drive to your favorite fishing hole, be the first one there!

With GM's legendary Fast Burn cylinder heads and 383 cubic inches, the ZZ383/425 delivers incredible

torque with smooth, linear delivery. If you're looking for a small-block package that delivers big-block

power, then you've found it. 425 horsepower at an incredibly low 5400 RPM, and 460 ft-lbs. of torque

at 4500 RPM make this the ideal hot street engine or off road powerhouse. The excellent air handling

and combustion characteristics of the Fast Burn cylinder heads combined with the ZZ383/425's 3.800"

stroke, make this engine the benchmark against which all other 383ci small-blocks should be measured.

And it's tough, too. The 4340 nitrided and induction hardened crank and unique forged PM rods see to

that. The 9.1 to 1 compression ratio ensures that the ZZ383/425 is 92 octane pump gas friendly. The

ZZ383/425 gets a stout .509/.528 lift steel camshaft, with 222/230 duration at .050 lift. Hydraulic

roller lifters and GM's time tested 1.5 to 1 roller rocker arms round out the valve train. And, of course,

it has the Fast Burn head's lightweight stainless steel valves and retainers for reliable performance at

extended RPM. GM's testing was completed using a single plane intake 750 mechanical sec carb, 1-3/4

primary x 33" length headers with 4" collectors. If using a dual plane intake, expect to see a drop of

15-20 hp.

12605117 - New from GM performance parts, Partial engine assembly used with GM 10067353 (Universal 350& 12499529 (290 HP 350) Built from all new parts, assembly includes: Cast iron 4 bolt main block with 2 piece rear main seal, Non factory roller compatable, nodular iron crankshaft, Powdered metal connecting rods, Dished aluminum pistons (12cc dish), Brass freeze plugs, Cam bearings, Can be used in marine applications, Provision for mechanical fuel pump, Requires pre-1986 oil pan Note: Oil Pump Is Not Included When used with 76cc heads compression ratio will be 8.5:1 When used with 64cc heads compression ratio will be 9.6:1 When used with 62cc heads compression ratio will be 9.8:1 When used with 58cc heads compression ratio will be 10.3:1

For those who want to build their own custom stroker small-block engine, this partial engine comes with the specially modified block, 3.80" forged steel stroker crankshaft, heavy-duty connecting rods, hypereutectic pistons, bearings, oil pan, oil pump, front cover, balancer, and 12.75" flexplate. This partial engine does not include a camshaft, lifters, timing chain, or cam sprocket. The oil pan is assembled loosely on the block so it can be disassembled without destroying the pan gasket. All parts needed to complete the engine are available from your GM Performance Parts dealer.