I'm wrenching on a 351W here trying to get the heads off and there's one last bolt that I can't get to budge with an impact wrench or a 1/2" breaker bar. What's my next step? A 3/4" breaker bar?

 

I have used a BFH to shock a bolt and it seems to help (BFH big ******* Hammer)

Good luck, Johnny

 

I got it. It just took enough gentle coaxing.*







*hard whacking

 

Make sure you replace the headbolts with new.

 

I think I might just end up junking the car. It was having radiator boil overs and oil in the coolant, but I don't see any obvious blowouts in the gaskets. The water ports of the gaskets are mostly blocked, so that would explain why the coolant was boiling when the engine was hot, but it wouldn't explain the oil in the coolant. Might be cracked heads, but the engine has 237k mi. on it, so no point in putting new heads on it without rebuilding the engine, and the car isn't worth that much.

 

So what kind of coolant was in there? If someone mixed "Dexcool" with the green stuff, then that would plug up all your ports and effectively shotgun the motor. And yeah, with that kind of mileage it has probably seen happier days since most 351Ws were only good for about 100K before they waddled out the thrust bearing and started to overheat.

 

I've owned it for 15 years and I've only put the cheapest green stuff in there. The stuff blocking the ports is orange and looks like it might be rust. I did let it get rusty once or twice on accident, but I don't know why it would build up in the gasket like that. I also poured head gasket sealer in it last year, but I don't remember it being orange, and I think it was boiling over before that.

 

The overheating/boil over problem likely began with a poor flowing t-stat, rad tubes blocked by calcium and/or possibly the water pump . The head gasket sealer probably sealed the deal .
It has seen many miles so I'm sure the car paid for itself many times over .
If you got that far and it still ran no to bad to pull the head/s, I would flush the engine out well, slap it all back together, check/ throw a used rad in , new water pump and t-stat and drive er' until it quits.
You have nothing to loose at this point.