351W Rebuild

[braxus]

Just doing some parts searching for a 351W rebuild for a 1990-93 Mustang LX 5.0L.

This will be my third time doing such a swap in Fox bodies, but its been some time since the last time. Anyway Im wondering about compression ratios and cam choice. I decided on a custom grind cam from Comp Cams with a 212/220 duration at .050 and 533/544 lift. This will be a retrofit roller cam using lifter parts from Comp. Anyway using pistons from Probe Industries, they have two choices. One is a dished 351W piston with a 15.9cc dish, while the other is a flat top with valve reliefs. Being the cam I will be using is for low to mid range performance with a lower duration, and this car is running EFI fuel injection with EECIV, what is the highest compression ratio EECIV can run with with a lower range cam? Is it in the 9s or can you go up to 10.3? I know a lot of motors today run close to 11s, but Im not sure how well EEC 4 can handle that, especially if the cam is rather mild. Any thoughts? Im trying to keep streetability with mileage as a concern, since my last 351W I was only getting 200km on a tank of gas with a midrange cam and flat-tops.

One last question. Do you have to use the 351W EFI fuel injector rails from the truck motor or can one use the ones off a 5.0L? And if I do use a 351W EFI fuel rail, will the ones off a 90s truck motor connect up to the existing feed line in 90-93 5.0L Mustangs? Im just concerned the fuel connector will be in a different position on the truck motors then the Mustang.

[goodyear1984]

you can run 11to 1 if you want to.but getting it tuned will be the best thing to do to get the best performance and you said your worried about gas millage.if your smart you will call the cam company and tell them the specs of you motor so you get the "best"cam for your ride.you didnt say any thing about heads so i will assume u have stock heads and a cam thats has good low to mid will be good if you have stock heads cuz they dont flow good.alot of people make the mistake of just trowing a cam in there car and not really being the right one.if u call a good cam company they will want to know the engine specs,transmission,rear end gear,weight of car.i am not saying the cam you picked is the wrong im just saying make sure its the best for what you have,just do your homework.i dont like comp cams because you can call them 5 times and get 5 different answers.as far as the fuel rails idk,id have to think they would,just test it out.good luck