Quick Answer

Are 781 heads any good?

The 781 heads are the best cast iron large oval port heads GM ever produced for the big block Chevy engine. They are worth rebuilding and respond well to pocket porting, bowl blending and larger valves. They will easily support over 500 horsepower. They are a very desirable street head.

Are 781 heads open or closed chamber?

Are 781 heads open or closed chamber? The ‘781 is the best choice for a 396 because it has the smallest open combustion chamber to help with static compression.

What are peanut port heads?

For the uninitiated, peanut port refers to the small, oval-port heads used on the Gen-V 454 truck motors run prior to the introduction of the Gen VI in 1996.

Which is better open or closed chamber heads?

Open and closed chamber cylinder heads differ in combustion chamber capacity. Although open chamber cylinders offer easier flow, the closed chamber cylinder is better for performance. Compression ratios are also affected by the size of the chambers.

Can you put 454 heads on a 396?

For example, tossing a set of 454 open-chamber heads on a 396 could radically reduce the compression ratio because of the roughly 10cc larger chamber on a short-stroke engine. Production big-blocks all the way into the mid ’90s were always flat tappet camshaft engines.

How much horsepower can a 454 make?

How Much Hp Can A Stock 454 Block Handle? In other words, a 454 can handle almost 600 HP (454 x 1.16).

What is a Gen V 454?

Gen V(5) Big Block Chevrolet Engine Differences

Produced from 1991-1995, these Only came in a 454 cubic-inch configuration. They had a one-piece rear main seal, oiling passages closer to the cam and every block received four-bolt mains. Gen 5 BBC’s saw cast aluminum valve covers and front covers for better sealing.

How much horsepower does a 454 Vortec have?

454ci/L29: Rated at 290 hp, The Vortec 7400 is the last generation 454, with the same 4.5×4-inch bore and stroke as before. Like the Gen V, all engines feature four-bolt mains.

Are aluminum heads worth the money?

Yes they are worth it. Pretty much every aftermarket head is worth a good power increase over any stock head. I like the aluminum heads since they are easier to port, repairable, and give a nice weight reduction. They usually are only a few hundred more than the iron heads.

Do cylinder heads increase horsepower?

Buying a new head that has four valves per cylinder will dramatically improve airflow in and out of the engine and this can improve power. Using performance cams can also make a big difference.

What does CC mean on cylinder heads?

One of these checks is cc’ing the heads (cc = cubic centimeters). This is a process whereby we physically measure the volume of the combustion chamber. It’s important to do this because it ensures consistency among all the cylinders.

What is the difference between a 396 and a 427?

The 396 has the smallest bore of 4.09″ and a 3.76″ crank. The 402 (not the 400 SBC) was a factory over bored 396. The 427 increased the bore to 4.25″ and still had the 3.76″ crank. The 454 used the same bore as a 427 with a stroke increase to 4.00″.

Is a 396 a good engine?

The 396 is a good revving engine, so you’d want to run a steel crank so it would live at the rpm you’d have to run it to make HP. And probably a roller cam, as flat tappet cams in big blocks have a nasty habit of “going away” relatively easily.