I found a salvage yard 4.9 from an '85 E250 van. I plan to rebuild it and put it in my '85 F150 4x4.
The engine had air in manifold and the dreaded feedback carburetor. No worries since I'm replacing exhaust manifolds and going with a new intake and carburetor.
As I was tearing it down, I saw that the area were the fuel pump mounts is not machined out. I haven't checked the block numbers yet, but I'm assuming this is somehow an EFI block.
So - do I have the block machined to accept the mechanical pump or go with an electric pump? If electric - any tips? I assume I'll need to regulate the pressure from it and of course wire it so it's on when the key is on.
I'd rather stay with the mechanical and it doesn't SEEM too tough to machine it out.
Assuming this IS an EFI block, am I in for any more surprises?
Since it was carbed, I don't think it's an EFI head but who knows?
You could just use an inline fuel pump. They are a little more expensive than the mechanicals, and once you get the milling done, and perhaps make sure there is a cam lobe to drive the pump, it might cost equal. I personally ran a 650 cfm on the cheapest electric fuel pump O'Reilly had. No return line needed, never a leak, never a problem.
As far as I am aware, the block is different only in the sense that the fuel pump hole was not machined out. Easy fix.
The head will have 3 extra holes for the intake/exhaust manifolds, if it's from an EFI engine. 13 = carbed, 16 = EFI. The 13 bolt holes are in the same place, the 3 extra holes just make it easier to install the 3 separate manifolds for EFI. If you intend to go with the EFI exhaust manifolds, having an EFI head will just make it easier to install them.
The cam does appear to have a lob to drive the pump. I may end up replacing the cam and if I do, I'll be sure to make sure it works in that application.
The head does have 16 holes and I am considering EFI manifolds. I'm still undecided on carb / intake choice but I have a little time on that; not sure how long the machine shop will take.
I'm really just looking for decent performance across the board with good low end torque. Just a solid, dependable engine. If anyone has any intake / carb suggestions I'm all ears. I hear on a basically stock engine, i'm looking at around 300-400 cfm range?
I'm not experienced on the 300, but I do understand something about carb CFM ratings. And given that I'd stay away from a 2bbl and go with a small 4bbl. The reason is that you are always running on one set of venturii on the 2bbl, so they have to be small enough to give good economy and throttle response but at the same time large enough to allow the engine to wind up. But a 4bbl uses the primaries except when you need the extra CFM, so they can be both small enough for economy/throttle response but large enough for power.
The exception would be if you found a progressive 2bbl where you run on the primary, singular, until you need the power. Like some of the Webers. Here's a link about carb selection of the inline engines that may help.
The Offy DP seems to be a popular choice with the guys in the straight six section.
These same guys also tend to report that a 600 CFM carb just works better than the 390-465 CFM models. No clue why, but many start with the smaller carb, and end up going to the larger one, and claim it just runs better all around. These are the guys with stock to lightly modded engines.