IRONMAN

Sorry for my ignorance but what cylinders are involved in the double swap? and is there any advantage on a carbed 600ci engine at a lowly 5500 rpms? wouldn't you need to completely redesign the intake for this type of double swap? Seems like it might be easily done successfully on an efi setup though. CI

f311fr1

Zul does the swap

320es

Ironman, It switches the 4th and 7th cylinders. The intake wouldn't make any difference. It doesen't know when the cylinder is supposed to be drawing in air.

45SS

Anything free is worth it. I think the big deal may be harmonics in the engine.( Timming chains, dist. gears ETC) Only time may tell on this. If he was still alive Smokey Yunick could chime in this type of thing would be right up his alley.

ROTAX454

My understanding of the 7/4-3/2 cylinder swap is this (from professional tuners---clearly not me): The 7/4 rewards you with some added HP, up on the RPM. The 3/2 rewards you with some added torque, lower on the RPM.

I do agree that it may be very slight on the added power, and
to purchase a custom grind cam just for the cylinder swap may not be worth the $. However, if you ARE changing the valve timing via a cam purchase, a custom grind cam would allow you to add the cylinder swap at a very low cost. All provided that a cam core is available for your particular timing and lift requirements. IMHO

jeff1000man

Seriously, this is for a high RPM and big cam combination at the same time. Otherwise, you will see nothing worth the hassl.

scarrab30

I did the 4-7 swap on my 540's. I did not pick up any noticeable power. They dynoed out almost the same as a regular fireing order cam. All i did was swap cams with the same specs, just a 4-7 swap. They don't seem to have the harmonics of the regular fireing order. Brian

ghittner

I did the 4-7 swap on a blown 900 HP motor but thid build is all new so I can't comment on difference. Dave Crower recommended it so I did it. No problems and this is a BIG cam w/ BIG duration on a blown 498.

code blue

Thanks for all the help. I'll use that plumbing idea. I have SS fittings and High purity SS tubing at work. Won't cost a dime!! I'll give Rmbuilder a call too.

vette131

just noticed the double swap gives the engine the same firing order as many ford engines!! things that make you go hmmm