I am in the process of getting a engine('00ish 5.4) from a junkyard(working or not) and I am going to rebuild it with a forged rotating kit from HERE and I wanted to know should I have to bore out the engine to +.020 or +.030 would I be okay to run a supercharger or should I try and avoid boring it out.

Also what compression ratio should I run, 9.60:1 or 8.89:1, which one would give me more power with the supercharger and which one would be safer or for a daily driver/weekend fun vehicle

 

I was told not to go larger then .020 and lower compression is safer with boost.

 

makes sense and I will be sure at least for safety sake to not go over .020 should I need to bore it out

 

I do not believe that going to 30 over would be a problem, others have done it. But I would say go as small as you can find inexpensive psitons. As far as compression goes, boosted motors should have less compression than NA, ie less than 9 to 1. Many companies out there have pistons with 15-18cc dish that are in the right neighborhood. Always depends on how much boost you are going to run and how your going to run the it (truck/motor).

 

if you run a centrufigal you can get away with higher compression easier

boss1984 is like 10:1 with his eaton

 

I am hoping to run a roots style blower since I dont really like the way the centrifugal one looks but I still need to read a little more into what the differences between the two of them

 

General rule of thumb for Modulars is not to exceed 0.020 over especially with a power adder. You are only looking to gain about 1.9 cubic inches more going 0.030 (.020 will give you 333.5 which is marginal over stock) over and risk bore distortion and cooling issues. Superchargers and especially turbos like more stroke due to better effective cylinder charging. If the fuel is good in your area then I'd go for 9.0:1 compression. If your fuel is oxygenated swill (ethanol in part) then I'd go for 8.5:1 for the extra margin of safety. I'd also opt for the CP pistons as that is one area you really don't want to cut corners on with 5.4's. The pistons are under much greater stresses than typically found in gasser engines as it is.

 

good luck finding a used supercharger or are you going to modify a 2 valve mustang one???

 

I dont know I was thinking about trying to find a used lightning one or buying a whipple or a roush supercharger

 

Hes building a 5.4

Phil

 

There's a L supercharger and manifold on NLOC rForum ight now. It doesn't have all the vacuum lines/wires.

 

duh, dunno know I missed that, I did catch that he had a 4.6 from his sig, lol

 

talk to steiny5.4 he's getting ready to sell a swap