4/7 cam swap

Have anyone ever tried one of these cams with blower cars?I know Lunati is putting one out on the market I think Comp as well.Suppose to be worth a little more hp.I did a search and did find some info in the advanced forum.I was hoping some over here had already tried it.Any comments.Thanks fellas

I run one in my *street* car. My 355/afr regular 210's/D-1 16lbs/ makes 650+ to the wheels with it. This one is a custom grind from comp. I have been running them for 10 years in my race car (lunati custom) so it is pretty common for me. If you are running a TPI, HSR or a LT-1 it is a real good addition.

what's a 4/7 cam?

what's a 4/7 cam?

Changes the firing order from 1-8-4-3-6-5-7-2 to 1-8-7-3-6-5-4-2

I have been wondering about this as ell for some time for one of our vettes running an LT4, does it change any other characteristics of the motor for those of you who have done it..? thanks!

Chris

I've considered doing this on my next motor. Wasn't sure how it would act with EFI, though I doubt the computer would notice by swapping the plug wires and cams. Anybody know how much just the swap itself is worth?

I have been wondering about this as ell for some time for one of our vettes running an LT4, does it change any other characteristics of the motor for those of you who have done it..? thanks!

Chris
I don't know about the stock ECM but since you are sequential you need to change when the injectors fire also.

I don't know about the stock ECM but since you are sequential you need to change when the injectors fire also.

true...

What would be the point of doing this???

Hey Biggtime thanks for the reply.As a matter of fact I was thinking of going with a HSR.Doug Flynn over at Holley says they will be coming out with an intake that matches the1206 heads just digging up ones who have done this already.For others who would like more info do a search in the advanced tech forum.Thanks fellas

What would be the point of doing this???


More power.

These have made a noticeable difference. :)

I am ordering a new cam for my race car and am going to do a 4/7 swap. Funny GM never figured this out. Anyone know who did?

Rich

I am ordering a new cam for my race car and am going to do a 4/7 swap. Funny GM never figured this out. Anyone know who did?

Rich

I learned it from Radar and Jenkins back in the early 90's. I know Jesel new about it also.
If you are using a factory style retention plate make sure you tell them when ordering as it takes a special core.

I learned it from Radar and Jenkins back in the early 90's. I know Jesel new about it also.
If you are using a factory style retention plate make sure you tell them when ordering as it takes a special core.

Thanks foir the info. It's a BB chevy and I believe Comp (where I get my cams) does have a core for it.

Rich

Thanks foir the info. It's a BB chevy and I believe Comp (where I get my cams) does have a core for it.

Rich

I get most of mine from comp also. When i ordered my smallblock one i forgot i was using a roller block and just gave them the core numbers. Lucky for me they called back. You not putting a big block in your camaro are you?

i dont have any experience with this myself, but my understanding from Nascar and NHRA engine builders who have done research on the subject is that the power gains from a 4/7 swap is due to it allowing better fuel distribution on a single carb intake. if that is the case, i wouldnt think it would do much for an EFI car. also they have said along with the 4/7 swap, that swapping 2/3 at the same time results in the best gains (sometimes a .5% hp gain). on dual carb intakes where fuel distribution isnt as much of an issue, they said there were no gains. interesting that if you swap both 4/7 and 2/3, you end up with the LS1's firing order. GM engineers stated that they came up with the LS1's firing order to reduce crankshaft stress and didnt mention any power gains.