Hey Guys,

Fairly new here, did a search and couldn't find much on how far one can mod a SD truck vs. a MAF truck. I'm talking on top of intake, tb, headers, and exhaust. I bought a SD 460, and am wondering whether I should mod it to what it can handle, or if it would be worth the effort to swap it out to a MAF setup.

I would like to port the factory heads, rollerize the valvetrain with a retrofit setup from Crane and run their smallest roller cam, and eventually(next year) do a custom turbo setup. I like the old platform, and want to fix up a '96-'97 rather than spend big $ on a new truck.

I recently picked up a '97 F250 cc 4x4 in Cali, but it isn't a MAF truck; however the price was too good to pass up, and the truck is in excellent shape.

 

The hard limit for SD EFI is the same for a stock MAF system, and that's 100% duty cycle on the stock injectors. You can do anything you want as long as the motor still provides a stable vacuum signal to the computer, that includes changing the cam or porting heads or intake, but cam selection is much more limited. In general that means under 216deg intake duration at 50 thou, and 114+ deg LSA. Once you max out the stock injectors you need a tuner or chip to go further. You can also add a blower to the SD system with an FMU to increase fuel pressure.
With MAF you can use larger injectors and a scaled MAF meter to supply more airflow.. as long as emissions are no concern. If you also want/need to pass emissions you'll need a chip or tuner. Once you have a tuner the sky is the limit, you can use pretty much any cam you want and as big an injector as you need, even a blown motor can be calibrated to run without an FMU. I general, the further you get from the stock motor the better the results you will get with MAF and a tuner over all other options.

 

FWIW, I'm running the set-up in my sig with 100% stable operation with the stock SD system. I do run a FMU for the blower. Like Conaski said the injector duty cycle is a limiting factor and you have to be careful with cam selection that drops the vauum to low and freaks out the computer.

Regards,

 

One other option I'm looking at is an aftermarket efi, one that plugs in to the engine harness. I'm lacking in details, but the guy told me that it doesn't use a MAF, and he can plug in to either the SD or MAF factory setup. It's about $12-1300 plus dyno-tuning, which he said would not take very long, 2-3 hrs.

So with that said, I am wondering how much would be gained by rollerizing the 460 valvetrain for an efi setup? When I talked to Crane, they had never done one for a street efi truck, but were very interested in results. They recommended either of their smallest roller cams (200-212 dur @ .050, 53x/55x lift, and 216-228 dur @ .050, 55x/580 lift). While the lift seems high, he said b/c of the roller it's no problem, and that idle would still be good. How much of a jump is this from the factory cam, and with ported E7 heads flowing 290/210, what kind of power could a guy expect n/a, b/c it will be a year before I will be able to do the turbo.