Fox Picking An Engine


Oct 15, 2013
Im finishing up my interior soon and want to start on some power next. I currently have the stock 5.0 in my 89GT and wanting some opinions on whether to build the 5.0 or get a 351w for it. its going to be a street strip car and would like to put down 450+ to the wheels without power adders. I would also be redoing the entire engine either way. I want the engine to last and not have to redo it in the future or break it. Im not an engine expert so will be using a manual to help me. i do want a roller cam have read up a bit on them and they seem to make the most power. thanks for your help
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450 rwhp out of a n/a 302 based motor is almost 550 crank HP, not an easy task n/a. You will definately need a boss or dart block for a 302 and some major heads to get there. For example, my 85 had a 347 that was in that rwhp neighborhood - r302 block, 11.5 to 1 J&E pistons ,Eagle crank forged , .675 solid roller lifer cam, TFS high ports, victor jr intake , intake and heads ported, BG Cold Claw, hooker 1 3/4 long tubes, and X pipe. Had about $10k in the motor. Best time was 10.26 @ 127 mph It was not something I drove on the street regularly.

I think you would have a much easier time hitting your goal with a 351 stroked to 408. It will me much more streetable and less money to build.
Stroked 351 would be cheaper and more streetable than a 302 at those power levels. $4K budget is probably going to require some astute buying of some used parts to get there. New heads alone in that power range are $1500 to $2K.
If you want a 351, get one out of a 95-96 F150/Broncos. Those are factory roller. Also, Ford continued to use that body style on their 3/4 tons in 97 so I'm pretty sure you could still get a 351 in a 97 F250. So that may help in finding one
Well if it isn't set up for roller from the factory, it must be converted. Which from what I've seen on a 351w, it requires a lot of grinding in the lifter valley. Also have to drill and tap the lifter valley for the little spider thing that holds the lifter retainers in place. Or you can always go with the lifters that have the link bars, that way you wouldn't have to drill and tap the block for the retainer
You're not going to get there on your budget. The heads will be over $2k. I think you would be better off with a 408 engine. The extra stroke is to keep the revs down. With the stock stroke you would have to rev it to high and end up needing a four bolt block.

You're not going to get there on your budget. The heads will be over $2k. I think you would be better off with a 408 engine. The extra stroke is to keep the revs down. With the stock stroke you would have to rev it to high and end up needing a four bolt block.


are you talking stroking a 351w to 408? is that just a stroke or with a bore?
I want a streetable car most of all. so if its stroked to keep the rpms down that's what id be looking at. in the research phase now. switched from the ls1 over to a 89 5.0 so relearning the ropes
The over bore is pretty much just incidental to the rebuild process. It has very little effect on the performance. Taking it from a 3.5" stroke to a 4.0" stroke will make it a lot more streetable. The performance you are looking for is very doable, and streetable depending on your definition of it anyway. It's just going to take a little more money.

In my opinion, 450 rwhp from a NA stroked 351 is going to have some "nervous" manners on the street, though taking it up to 408 would help in that direction. If you really want street manners, supercharging can give you the best of both worlds. Regardless, traction will be an issue, with normal street tires just causing lots of frustration.
Yeah you're gonna have to do some significant chassis/suspension upgrades for the car to handle that much HP. Sub frame connectors, upper and lower rear control arms, torque box reinforcements, the list goes on and on. Then you get in to STOPPING the car with that much power. You may end up doing disk brake and 5 lug conversion, and hell may as well do hardened axles while you're there and rebuild the trac lok while you're in there. You could easily spend 15k on a fox if you're not careful. Trust me. Most of us on here have done it. Lol. Oh and also have to address the trans. You didn't say 5 speed or auto, but an AOD in stock condition won't hold that power, and if you have a T5 you're gonna need one mean clutch, and then who knows if the T5 will hold up. The T5 is just like the 302, some get lucky and run big power while others blow em apart at 300 HP.

If your budget for the whole car is 4k, you may as well just put an Explorer top end on it for now, drive the piss out of it, and then save up a lot more money. But if 4k is just your limit for the engine alone, then you'll be doing pretty alright
I think it will be ok. It depends on how you build it. My 10:1 347 should be around 400rwhp, maybe a little less, and it has great street manners. Good tune and a good cam makes all the difference. Another half inch of a stroke built on the same principles and 450rwhp should be attainable. Fuel injection is going to be an absolute must.

4k for engine and guess I understand the need for supporting parts to help the car like suspension and brakes. Plan on doing those in phases in due time. So most agree on a stroked roller 351w. Now to begin looking for a block and some reading material on the engine