4/7 Cam Swap... Does LS3 benefit from it?

[Ken_]

Hey, I've heard about the 4/7 cam swap from one of the other forums, and just getting more information.

If you don't know what it is, it's about doing a change-up of the firing order. More usable power in the mid-range and an increase in HP (we're not talking astronomically).

Here's an article http://www.hotrod.com/techfaq/113_07...s/viewall.html

Has anyone done this with their LS3 yet?

[biggerisbetter]

[blake-b]

It looks like it has already been done by GM. They are talking about a regular SBC, not an LS engine. The factory SBC firing order is 1-8-4-3-6-5-7-2.

From the article (bold added by me):
"So the OEs may have aspirations of smooth reliability, but what about the power benefits? James Humphreys of Lunati thinks it was probably NHRA Pro Stock racer Steve Schmidt who first had success making added horsepower with the firing-order switcharoo, resulting in today's aftermarket offerings of 4/7 swaps. It's also common to see juggling of cylinders 3 and 2, usually in conjunction with the 4 and 7 switch, and that results in an order often called Corvette style, or just "C," and it's the same as a new LS1 (1-8-7-2-6-5-4-3). However, our test was of two Lunati solid-roller cams that were identical other than the 4/7 swap."

The article is from 2009 as well.

[litle88]

Lmao!

[Ken_]

Sounds like you are ridiculing me for asking a question. For some of us, me included, the LS is a new platform, and I never messed around with GM stuff until I got my 2SS.

2009, 1999 or 2019. Why does it matter when the article was written to someone who is just now getting familiar with GM products/aftermarket?

Thanks for the added information, but try not being a dick.

At least I didn't ask what kind of factory carb I need to put on my LS3, for that I would deserve ridicule.

[blake-b]

I, myself, had not heard of this same thing until literally Monday. A friend asked me about it while swapping, degreeing, measuring PTV and pushrod length on my car. I did some research and discovered GM did it for us. I was simply trying to enlighten you. I copied and pasted because a lot of people won't read the article or they will skim over it and await answers within this thread.

If it hadn't been done by GM, with the article being 4 years old, there would be much more information out there about it being used on the LSx platform. I put the date in there to save people time from reading it.

If you took my reply as ridicule, you took it incorrectly. I was simply stating facts.

Your location says KU. As in University of Kansas? If so, we are practically neighbors.

[Pro Stock John]

Good share Ken, I remember one time I was in a conversation with a noted LS engine builder who though maybe this new firing order is one of the (many) improvements that makes the LS family engines so killer.

[SC2150]

Legitiment question. We do this with our drag BBC motors....Like the rest replied, GM already has the LS firing improved.

[trw427ss]

I have made lots of 4/7 swap only cams for race LS engines with great results. Comp Eliminator and Pro Stock have tried lots of firing orders and the one that always makes more power is the 4/7 swap not the 4/7-2/3 swap like the stock LS!

[MikeOD]

Originally Posted by trw427ss

I have made lots of 4/7 swap only cams for race LS engines with great results. Comp Eliminator and Pro Stock have tried lots of firing orders and the one that always makes more power is the 4/7 swap not the 4/7-2/3 swap like the stock LS!

The 4/7 combined with 2/3 was done by GM to make them run smooth...smoother than the older firing order...I guess really you're swapping 2/3 back in search of power and not changing 4/7?

[Ken_]

Originally Posted by litle88

Lmao!

I guess it really wasn't a stupid question, was it?

[Ken_]

Originally Posted by blake-b

I, myself, had not heard of this same thing until literally Monday. A friend asked me about it while swapping, degreeing, measuring PTV and pushrod length on my car. I did some research and discovered GM did it for us. I was simply trying to enlighten you. I copied and pasted because a lot of people won't read the article or they will skim over it and await answers within this thread.

If it hadn't been done by GM, with the article being 4 years old, there would be much more information out there about it being used on the LSx platform. I put the date in there to save people time from reading it.

If you took my reply as ridicule, you took it incorrectly. I was simply stating facts.

Your location says KU. As in University of Kansas? If so, we are practically neighbors.

Thanks for the enlightenment, and yes, I am sure that this topic would be more relevant than what it is if GM hadn't incorporated it in our current platform.

In actuality, it was the guy after you with the LMAO who got my nerve.

I'm in Kuwait. This is where I live, and I rely on this site to get more information since we don't have much else in ready available information or examples. If it is known in some circles, most people keep it a secret.

[thahemp]

Originally Posted by Ken_

Hey, I've heard about the 4/7 cam swap from one of the other forums, and just getting more information.

If you don't know what it is, it's about doing a change-up of the firing order. More usable power in the mid-range and an increase in HP (we're not talking astronomically).

Here's an article http://www.hotrod.com/techfaq/113_07...s/viewall.html

Has anyone done this with their LS3 yet?

Originally Posted by litle88

Lmao!

It would be funny if you already knew the firing order was implemented on the LS3. I didn't, but litle obviously did!

[litle88]

Originally Posted by Ken_

I guess it really wasn't a stupid question, was it?

It was!

Your search FAILED you! Your reading FAILED YOU!
You were too lazy to read the article, you sensitive azz!

I remember this article because its right here in the hotrod/GM hightech performance shelves where I take a shit!

Look or read 5-6 PARAGRAPHS down and at the end of one you'll read this!

. If you simply renumber cylinder locations of the older Ford engines as if they were Chevys, you'll discover that the firing order is, in fact, identical to GM style. Further, if you take the 351 and late-5.0L Ford firing order and renumber the cylinders like a Chevy, the firing order is 1-8-7-2-6-5-4-3. That's the same as the Chevy Gen III and IV (LS-series) V-8s.

YES IT WAS DUMB!!!