Eric in Wyoming
Active Member
What's happnin yall, been awhile!
So the 5.4 in our '97 EB is approaching 310,000 miles. Runs like a top still, but the other day I started her up and noticed what sounded like a slight rod knock that went away after a few seconds. Got me thinking it's time to either put the old girl out to pasture and get another vehicle, or start prepping for a rebuild now. For the rebuild option, I'd want to swap on some PI heads/intake and some longtube headers to go with the already - upgraded exhaust. I know I'd need PI-era pistons to do that and not need higher octane fuel.
I currently have a lead on a PI 4.6 engine, and from what I gather the PI 4.6 and 5.4 both use the same pistons and heads, heads have the same combustion chamber volumes and cams, pistons have the same compression heights - so how then do they achieve the same compression ratio when the 5.4 has such a longer stroke than the 4.6??? If I go this route I don't wanna end up with an OEM-spec engine that pings on race fuel.
So the 5.4 in our '97 EB is approaching 310,000 miles. Runs like a top still, but the other day I started her up and noticed what sounded like a slight rod knock that went away after a few seconds. Got me thinking it's time to either put the old girl out to pasture and get another vehicle, or start prepping for a rebuild now. For the rebuild option, I'd want to swap on some PI heads/intake and some longtube headers to go with the already - upgraded exhaust. I know I'd need PI-era pistons to do that and not need higher octane fuel.
I currently have a lead on a PI 4.6 engine, and from what I gather the PI 4.6 and 5.4 both use the same pistons and heads, heads have the same combustion chamber volumes and cams, pistons have the same compression heights - so how then do they achieve the same compression ratio when the 5.4 has such a longer stroke than the 4.6??? If I go this route I don't wanna end up with an OEM-spec engine that pings on race fuel.