OK, so here's what I've got. '91 F150 Lariat XLT super cab, 351w, E4OD, 198,000. Engine needs a rebuild. Still runs and drives, but the times coming. I'd like to get a little more torque out of it without giving my bank account a stroke and am looking for some input from those much more knowledgeable than myself. Right now I'm just gathering the parts so I have everything in place to get this done the first part of March.

I know that the GT40 heads off of a '96 or '97 Explorer or Mountaineer will work on this engine if the bolt holes are bored out. I've already got a set tracked down and I pick them up on Monday.

What else can I do to this engine that won't break the bank? Let's say $1500 - $2000 after machining heads and block.

What's a good oversize to machine too?

I know the basics of engines, but short of routine maintenance and changing gaskets I've never really delved into one, so go easy on me if my questions seem trivial.

Well you got the heads, a good cam, intake carb and exhaust to really let it breath, will liven your motor up quite well.

have the heads worked over so they will flow better.

Are you wanting to keep your truck FI? also is it a roller engine?
If it is you are going to need to get a good RV type cam that will work with a FI engine those are pricey as for going with a bigger bore the most common bore size people go to is .30 but it's not really going to do much for you power wise unless you go with a much larger over bore like .40 .60 the reason this is done is to give you more displacement, but I think you might want to stay away from that if your wanting to stay mainly stock..

Just all depends on how radical you want to make it, and your price range ($1500-2000 you mentioned). i know you said you just wanted to improve torque so a good set of heads which you've tracked down so i'd advise on getting them worked out a little, intake is also a biggy along with cam, are you going carbed or fuel injected like tex asked. How much torque are you aiming for?

I plan on staying fuel injected. It's not a roller engine, though I've read it's fairly simply to convert it into a roller.

Ultimately I plan to use the truck to pull a fifth wheel camper trailer and ATV most weekends during the spring and fall, and not having to use my grandfathers truck to do this will make my life so much easier. I'm not looking to race it or anything like that.

Already had the goose neck installed and used the truck to pull the camper from storage to the house. It did OK, but didn't seem like it had any balls to it until it got into the 1700 or higher RPMs, so I'm looking for more of the lower end torque. I don't know what the gearing in the rear end is, nor how to find out, so if that information would help, just tell me how to figure it out and I'll get it.

Aside from trailer brakes, this truck is completely stock as it sits. Really, the only thing I plan on doing to it is putting the front clip off of my step-dads old '95 on it (I much prefer the look and the headlights) and adding a leaf spring to the rear end so it doesn't sag so much with the weight of the camper and putting a leveling kit on the front end.

What kind of intake and cam would you suggest? Links are always good.

The heads should bolt right on without boring....I thought only 302's needed the holes bored in the block...but even then...ARP makes both a bolt kit and a headstud kit to compensate for that....I've got the bolt kit on my 302 (GT40 heads off a lightning).You need to have them ported out and worked over a little....throw some roller rockers on it as well.A mild RV cam would be a great upgrade for it as to pulling...I mean..they did put them in RV's.As to the rear end gears....look on your door sticker for the code and post it up on here.....if you can't read it....it's on the metal tag on your rear end.......for example 3L55 etc etc.Another thing with this is if you're going to be pulling...the E4OD HATES long term heat so you might want to consider upgrading your transmission cooler to something bigger.......Drop a line if I missed something...and by all means.....if you don't use all your budget send the remainder my way...my truck needs some upgrades heh heh.Good Luck and welcome to the site Bob.

flareside_thunder said:

As to the rear end gears....look on your door sticker for the code and post it up on here.....if you can't read it....it's on the metal tag on your rear end.......for example 3L55 etc etc.

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Will check in the morning, thanks.

flareside_thunder said:

Another thing with this is if you're going to be pulling...the E4OD HATES long term heat so you might want to consider upgrading your transmission cooler to something bigger.

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Check! Will add big honkin' tranny cooler to shopping list.

flareside_thunder said:

and by all means.....if you don't use all your budget send the remainder my way...my truck needs some upgrades heh heh.Good Luck and welcome to the site Bob.

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Whatever I don't use for rebuild or upgrades is going to a stereo and interior. Thanks for the welcome.

Bob said:

Will check in the morning, thanks.



Check! Will add big honkin' tranny cooler to shopping list.



Whatever I don't use for rebuild or upgrades is going to a stereo and interior. Thanks for the welcome.

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Ohhh goody goody, i can help with sound system and interior questions I worked at a restoration shop on interiors of vehicles, and well done my sound system as well as friends

You might also consider a different set of gears.

and a deeper tranny pan for more fluid capacity come to think of it....

The E4OD tranny in that truck is controlled by the engine computer, so you need to retain EFI or change the tranny too. The Crane 444232 is a very good upgrade from the stock cam, is SD EFI friendly, and a kit with lifters only costs about $200. To use a roller cam in this block you would have to buy the expensive link bar roller lifters($500) and new pushrods($50), and of course the cheapest roller cam you'll find is $200 alone, so it's not exactly cost effective considering it won't make a noticable difference in power over a flat tappet cam. Your goals will also require longtube headers, and as others have suggested 3.73 gears would be worth the cost and help lighten the load on your tranny. No changes to the intake are necessary besides port matching the lower to the heads, and just to be clear this does not mean gasket matching. You want the lower intake ports to transition to the heads smoothly, so take some time to align the intake with the heads and open up the last couple inches of the runners to the same dimensions as the head ports.

When rebuilding the block don't bore any more than necessary, the couple extra cubic inches gained means nothing to power production compared to how much you loose in block durability. Use flat top pistons with valve eyebrows for a nominal 9:1 CR, new bearings and ARP fasteners, and a good quality timing set.

Here's a DesktopDyno simulation for your proposed combo compared to a stock motor. I was very impressed with this cam in my 5.8, outstanding power and TQ.

flareside_thunder said:

The heads should bolt right on without boring....I thought only 302's needed the holes bored in the block.

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No. The 302 uses 7/16" head bolts, the 351 uses 1/2". So when putting heads from a 351 on a 302 you need to use bolts with wider shoulders or stock bolts with collars to make up the difference. When using heads from a 302 on a 351 you simply bore out the holes in the heads and use stock size bolts. The head bolt holes in the block should NEVER be bored out to use slightly larger bolts, they won't take the required TQ before stripping.

Sounds very reasonable Paul. Thanks for the Dino chart. Puts it much better prospective.

conanski said:

No. The 302 uses 7/16" head bolts, the 351 uses 1/2". So when putting heads from a 351 on a 302 you need to use bolts with wider shoulders or stock bolts with collars to make up the difference. When using heads from a 302 on a 351 you simply bore out the holes in the heads and use stock size bolts. The head bolt holes in the block should NEVER be bored out to use slightly larger bolts, they won't take the required TQ before stripping.

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Sorry Paul I meant it to sound the way you explained but i guess I didn't too well.I was under the impression that he'd be using 351w heads...guess I misread.
Bob, Paul is the cam expert and all around tech guy when he's on.He's helped me quite a bit in narrowing down cam options for my 302.

How about cranks. Can I do any upgrades in that department without having to get into a bunch of other crap?

No need to touch the bottom end at all except for bearings and rod bolts and to machine everything to spec where required. The stock crank and rods will support 500hp and obviously this combo is nowhere near that. The block itself will support upwards of 700hp if a forged rotating assembly were installled.

Shopping List

Going to get the crank machined and mains to match.
GT40 Heads
Crane Cams 444232
Transmission Cooler
Hedman Hedders 89270
3.73:1 Rear end Gears
Transmission Pan

Anything else y'all would suggest, or different parts?

Forgot timing chain set.
COMP Cams 2138 Timing Set

Put a shift kit in the tranny.

Have you got stock size tires on that.... or close?

conanski said:

Put a shift kit in the tranny.

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Can you point me in the right direction?

conanski said:

Have you got stock size tires on that.... or close?

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Stock