JRider

iTrader: (1)

My plan is to pull the heads off my 575sci to replace the head gaskets and then swap out the heads with AFRs. The exhaust port height is .3" higher than the stock heads. Question is will there be enough deflection in the CMI joints to allow for the .3" difference in height?

Ran-Dom 32

I don't think you will have any issue's, my cmi's were not lined up perfectly, but still fit

JRider

iTrader: (1)

Ran-Dom...what heads did you go with? Some heads have over .75" raised ports.

Whipple Charged

I don't think you'll have a problem with .3". But are you gonna have someone tune that ECM because thats opening a major can of worms. The heads are night and day different and the fuel injectors are super sensitive, so fuel psi will not compensate. Your gonna need an AF bung in the exhaust, should be able to install it in one tail pipe. Need a double jacketed bung, and then get a AF meter from Innovative Motorsports.

Dustin

JRider

iTrader: (1)

That just might change my thinking. It seems to be very fat right now everything being stock. So...even with the stock cam these heads are going to flow enough to lean it down and change the manifold pressure? My plan was to pull the motor next year and totally go through it and change the cam. At that point have the ECM worked...

Whipple Charged

The cam is junk, its a flat tappet, heads are ok, but still iron. But if you put good parts, the SC is too small, and no intercooler then raises another issue. I just had a customer rip his entire setup off because he did the same thing, then installed one of our SC's, he's up around 850hp now. But it was a major expense so I'm just trying to help you before you go down that path.

You can bolt the AFR's on, I think it will idle and run, but it won't be right, and with it being as rich as it is, it might make less power because the boost will drop to maybe 1psi, and there will be very little temp in those heads. Of course, I would install the 3" pulley and shorter belt, get some pressure in that motor and it will probably come alive. If you get the af meter, it would help, then someone could help modify the ECM for you off of your info.

Thanks,
Dustin

Nordicflame

iTrader: (4)

Just so happens I spoke with CMI yesterday as I just purchased two sets of Sport Tubes. Dave from CMI said that AFRs will add 1/4 width per side and about 1/8 in height.
Probably not an issue.

Dave