new SBC firing order?

[ironroad9c1]

anyone know anything about these new cams from comp? they switched the 4&7 firing order ,they have kinda high powerband though ,,,its in the newest summit mag page 142

[Matt@RFR]

People have been doing that for years and years. From what I understand, it basically smoothes everything out, better exhaust scavenging, more vacuum, etc. It requires no special parts other than the cam, and remember to write down the firing order!!

If it's physically possible, someone has done it to a SBC. I personally saw one that a guy machined his own heads and ran the thing backwards. Had a custom cam ground (backwards) and associated parts. He had side draft webers sticking off the sides of the heads and headers where the intake manifold would normally be. It was probably a $30,000 engine (in the early '80s) and made like 400hp. Looked really cool though!

[justanova]

speaking of cool things done to a small block chevy, does anyone have any literature on some of the engines that Bill Crower(correction?) made in the late 70's early 80's for indy racing, the ones where he closed off the normal intake ports and machined intake ports between the exhaust ports and used weber down draft carbs/or hilborn style injection with twin turbos? (ever since reading about it I have always wanted to try it, supposedly the only reason he quit making them is because the sactioning body was going to require him to make the setup available to everyone at a reasonable cost, and he didn't want to let everyone have it. I read a small spot about it in hot rod a few years ago in one of their articles that they reprinted from back in the day. supposed to have like a 40% increase in flow.

sorry if I hijacked the thread.

[442olds]

They spin a lot of motors backwards for marine apps, but usually the intake and the exhuast ports remain the same.

The 4 7 switch is also supposed to help relieve the stress put on the block by the 5 and 7 cylinders firing one right after the other. But the cams available are ussually for all out race engines and I am not really sure how streetable they are.

[JamesJ]

like ironroad9c1 said I think that the new cams that they are making are comletly streetable. before you had to have someone grind a custom one for you but just like everything else, the public gets things that the racers did 10 years ago. when i get around to getting my motor built I plan on doing this.

[Brad]

I just talked to cam motion about this a few months back. Basically, they said you only see a gain in HIGH rpm and unless you are building a maximum effort race engine, theres no point. People are also doing a 4-6 swap too, but I understand you have to have a ls style cam core????? I've forgot alot that I need to know, but thats the short-sweet. Also, at the time (3 months ago) the 5/7 was'nt available in a hardened roller core. It also cost a little bit more to grind.

[69protour]

Hey guys, if you look at the thread I posted a while back named "Frank here it is" I forgot to put in there I am also doing the 4-7 swap. My engine builder says it smooths it out some and also gets about a 20 HP gain by doing this! The cam I'm going to be using is by Lazer. I talked with Bill at Lazer, Gave him the all the specs of the car and he chose the cam I'm going to be using. This guy is very sharp, nice to talk to, and helpful! He really knows his stuff! Trond

[ironroad9c1]

yea the powerband listed was above 4,000 rpm ,i was just curious