[chevyboy97]

hey guys, just wonderin how many horse-power will like hooker headers gain you on like a 402 or a 454 bbc?? thanks

[vinniekq2]

headers bolt to the heads,lol.
tube size and length is related to horse power produced with the sum of all parts.

dont buy big tube race headers for a mild street engine. 2 inch primaries are good to 650 hp or more.
Tell us about your application?

[327NUT]

Lots of variables, around town just crooozin you probably wouldn't notice anything except maybe the sound. Headers, and I mean GOOD long tube headers really make a difference performance wise at higher RPM. In a dyno application I've read where headers make as much as 30 or more HP......but again that's at higher rpm.

[F-BIRD'88]

The typical gain is 12%.

[chevyboy97]

Originally Posted by vinniekq2

headers bolt to the heads,lol.
tube size and length is related to horse power produced with the sum of all parts.

dont buy big tube race headers for a mild street engine. 2 inch primaries are good to 650 hp or more.
Tell us about your application?

So its a 1974 chevy shortbox 4x4 I had a 402 in it prety much stock til we pulled it the other day and found 1 broken piston and 1 or 2 pistons w/ broken rings...we were gona rebild it til today my dad herd of a 70's pickup with a 454 so i mite go take a look at that soon and maybe put it in my '74...if that 454 just has regular exhaust manifolds should i use them or my headers??

[vinniekq2]

Always use headers. Use a smaller tube primary pipe for near stock engines. A mild 454 will be a tire melter

[chevyboy97]

ya...thats probly what ill do...i guess we'll see...do you ever have problems with them melting spark plug wires??

[vinniekq2]

Take the time to use wire looms and separators to keep the wires neat and tidy and away from headers. If the wires get close to a header pipe the put heat socks over the ends of the wires.

[chevyboy97]

ok ya thanks found out that that pickup and motor are 1968's any idea about hp on that??

[vinniekq2]

what year is the engine from the 68 pick up?

[vinniekq2]

In 1970, GM pushed the performance bar higher with the introduction of the Chevy 454 V8. Unlike the popular Chevy 427 that was used in a wide variety of automobiles, the 454 was used only in high performance cars like the Chevy Camaro, Corvette and Chevelle. There were 3 different variations of the 454 that came onto the drawing board at GM during the 70s; the LS5, the LS6, and the LS7 which was designed but not produced for the general public most likely due to the massive smog restrictions that started lurking about in the early 70s. . Although the LS7 454 never made its way into any cars sold to the public, it was sold as a crate engine available through Chevrolet and claimed to produce around 500 horsepower.

[F-BIRD'88]

the 454 was used only in high performance cars like the Chevy Camaro, Corvette and Chevelle.



I had a Canadian built 1970 Pontiac Safari station wagon, Factory 454 /390HP LS-5 Chev motor.
Chev TH400 and a Chev 12 bolt axle.

That motor ended up in my 68 Chevelle with a LS-6 cam swappped in.

[vinniekq2]

My 330 horse LS-5 ended up with an L-88 cam. isky cloned version.that ended up in an 80 Camaro

[chevyboy97]

The pickup and motor both are 1968's and thanks for all the info...hopin to go take a look at the '68 in the mornin'

[vinniekq2]

I doubt the engine is a 68