91 F-150: Rehab 4.9L I6 or swap in rebuilt 5.0 V8

[w123fanman]

My dad bought a fairly clean 91 F-150 5-speed last year for use as the company truck and we've been going through and fixing things. The suspension is entirely rebuilt with added swaybars and steering damper, AC system totally redone with parallel flow condenser, totally new fuel system including tanks, and we had done some work on the I6 to get it running (bent push rods upon first startup after sitting forever).

We were having the classic Ford 300 issue of an exhaust leak at the manifold and that was making it unsafe to drive the thing, so we bought a set of headers thinking that we had a set of cracked manifolds. Turns out that the manifolds were not crack (very rare as I understand) but whatever idiots worked on it last didn't put in exhaust manifold gaskets. As we were installing the headers, one of the exhaust studs/bolts (which are NLA) broke in the head and we couldn't get it out. We already planned to do a clutch job and replace the rear mean seal plus motor mounts and all so we went ahead and pulled the engine, planning to have a shop extract the stud or put on a rebuilt head then replace the cam and lifters since they were starting to chatter. Turns out the head gasket had been slowly leaking at cylinder 6 (we thought this might be an issue before doing this) and eroded the cylinder wall slightly. It's going to need to be honed and probably new rings in the engine. We figure the cost of the parts we need is around $800.


So we decided to check out if there were any better engines around to start with or maybe a V8 to swap in. We found one and have been talking to a guy with a truck that has a rebuild on the V8 with not many miles on it that was totaled, for $500. Since I'm not an expert on older Fords, what would you guys do? The V8 is certainly a more attractive option, we don't need the low-end torque of the 4.9, the 5.0 seems like it would be a bit more comfortable cruising on the highway and has much better aftermarket support.