1800runsnew is offering a 454 HO. What is this engine compared to the 454 Mag? What year was it offered and what are the specs?

Thank you,

Kirk

As long as its gen 6 they are one and the same,`1053 steel crank,7/16 rods,forged pistons w/mini dome 8.75-1 compression,1010 steel pushrods,hyd roller [email protected],540 exh [email protected],425 hp crank/385 hp (at outdrive),single roller timing chain,1.7 stamped rockers,non-adj valve train,rect port heads w/118 cc chambers,2.19 int valves,1.88 exh valves,baffled 6 quart oil pan,pressed wrist pins. Contrary to myth,urban legend etc the 502 mag&454 mag do not have a higher nickel special marine block,exotic premium valves or any other internals that the 502ho&454 ho doesn't have. When mercruiser was still buying them from gm,they bolted their efi system on them,marinized them with all the other EXTERNAL parts required for marine use(raw water pump,sensors,cool fuel,merc manifolds etc) and called it a marine engine. The valve train is mediocre,gm actually rates the motor safe to 5800,merc sets the rev limiter lower for longevity and safety margin. In carburerated form these 454ho's typically exceed their 425 hp rating by as much as 15 hp,i hope this helps you,Smitty

Wow. Smitty, hell of an answer! I replaced A mag with an HO, although for some wild off the wall reason I did replace the head gaskets with Fel-Pro Marine! gained 3mph go figure? 250hrs now on engine without a problem.

Kirk, you can also check with Sallee chev! They sometimes have excellent prices?
http://www.sallee-chevrolet.com/
last time I check it was 4795.00 complete!
P/N 12568774
The new Gen VI 454 HO offers outstanding performance and value in an over-the-counter engine package for off-highway applications. It is the successor to the popular Mark IV LS-6 assembly, which has been discontinued. When equipped with an aftermarket four-barrel carburetor and artermarket headers, a prototype 454 HO produced 425 horsepower and 500 lb-ft torque.
The 454 HO is based on the “Gen V” big-block V8 that was introduced in 1991. This revised Gen VI engine design also includes a leak-resistant one-piece rear crankshaft seal, relocated oil passages, a redesigned oil filter pad with integral oil cooler connections, cast alum. rocker covers, and 4-bolt main bearing caps.
The 454 HO is completely assembled, less ignition, spark plug wires, carburetor, and exhaust manifolds. It includes a water pump, torsional damper, and automatic transmission flexplate. The 454 HO has a high-rise aluminum for barrel intake manifold and high-performance rectanguar port cylinder heads. Tese cast iron heads have open-style combustion chambers and 2.19/1.88” diameter valves.
With 118cc combustion chambers, the modest 8.75:1 compression ratio loves today’s pump premium gas and has no appetite for lead, octane boosters or other fuel additives. Its 2.19” intake and 1.88” exhaust valves and high lift .510” I / .540” E roller cam let it breathe with the best of the early muscle motors. If you want to use you muscle car’s fuel system with a mechanical pump, you can because the 454 HO GEN VI block has a conventional style fuel pump boss.

Bryan

Great info.

Thanks, sounds like a good motor for my 24 Pantera I'm selling.

Thanks again,

Kirk

454HO and the 454MAG have a different cam. Only difference i'm aware of. 454 mag is 224/224 duration with .483 .483 lift...

left off the last sentence .......

The 454 HO is not intended for marine use, and should only be used in 1976 and earlier pre-emissions street vehicles or any year off road vehicles.