Gentlemen; I have a 1989 F 250 with a 5.8 injected, 5 speed with 3:55 gears. The motor has 269,000 on it. I'm running 31 inch Dick Cepek Mud Country tires I'm interested in towing a large camp trailer, say 37 feet. I just completed a 20 month long restoration of the body and frame and it's time that I rebuild the motor. I keep seeing and hearing that a 347 stroker could be the way to go. (so essentially I believe that a 347 is actually a 5.0 litre that has been bored .040 over which is about all that a 5.0 can take). Am I accurate with my information. I see that I can get approximately 385 horse from this particular setup. I really don't want to go to a big block as the stock 351 seemed to be well fit for the original truck. I don't plan on doing tractor pulls so I do not have the need for a 7.3 diesel can I please hear from one or all of you senior bloggers for some guidance? Then on top of my primary question; should I be concerned with whether or not I purchase a stage 1 or stage 3 motor. I am contemplating purchasing a crate motor with most of the preliminary work already completed. I really need a senior gearhead that knows how to build motors. Any replies would be greatly appreciated. Thanks in advance. Paul

 

A347 would be a downgrade in a truck, especially one you plan on towing with. You could just do some upgrades to your old engine, cam, heads, etc. The newer blocks are roller cam and more desirable. I'm not sure what year that started.

 

For 302 I believe it was 92 and for 351 it started in 94 I believe for roller cams.


Personally I think putting a 347 stoker in would be backwards instead I would do a 408 if you wanted a stroker.
Problem is that 385 horses will all be on the top end (high rpms) so I don't think that would be the best for towing.


I would do like bashby says cam, heads, and similar on your old engine.
Trav

 

If I decide to go with a new 351 short block; what type of heads should I be looking for? I want to have 350 hp and up. In essence the horse power is variable but I need a fresh strong motor and I want it to snap when I am towing down the road at 65 mpg. If I am doing my homework correctly I need a mid-range cam for that snap at about 2500 rpm. I really know little about balancing and tuning a motor. So all of your advice is welcomed. I believe you are right about the 347 stroker being a hi revving motor and all the horses being on the top end. Good call bro.....

 

These are the heads I want to run on my dream 408 stroker build (once I get the money).
http://www.summitracing.com/parts/tf...-m61/overview/




I would have somebody verify these heads are going to be good on a build like you want since I am personally going more for the 400-450hp range.


As far as cam wait for Conaski to pitch in he will tell you exactly which cam you need. Personally I haven't chose one yet.


BTW: a good set of 4.10 gears would really perk that truck up. Our work truck is a 89 F250 351W ZF5 running 285 75 16s and 4.10s and it pulls great but I am willing to bet if it didn't have the 4.10s it would be a dog pulling. I personally can't confirm it because although we have a ton of trucks none have a 351W and 3.55 gears.
Trav

 

I wouldn't go 347 if you have the 351 in it stroke and poke that one 418 or 427 and you'll have a nice towing motor and I agree change the gears 4.10 at least maybe 4.56 depending on what rpm your turning going down the highway now

 

You want to tow a 40ft RV trailerand you don't think you need a diesel? Do you realize your truck isn't rated to tow anything even remotely close to that big and changing the motor won't have any effect on the rating.

Ignoring that for the time being I'm also going to suggest you do a 5.8 build, the block is far stronger which translates into longer life and it'll make the same power a 347 would make with the same HCI package on it and you save the cost of the stroker assembly. 350hp isn't much of a challenge for a 5.8 with the right parts, but for your uses you should concentrate more on building max torque and live with whatever peak HP it makes. There are lots of ways to do it, a set of AFR185 aluminum heads with a Twisted wedge intake and a Comp Cams XE264HR roller cam, or maybe use a set of Dart or RHS cast iron heads for greater tolerance to detonation. These combos should make over 400tq and about 350hp but if you want some real impressive torque put a 393 or 408 stroker assembly in the block along with that topend.

 

I guess I have a lot of reading to do before I understand what makes one head better than the next. I think I get the concept behind the larger intake valves but cast vs. aluminum, I'm at a loss. Is heat dissipation a consideration here? This twisted wedge intake; is it compatible with throttle body EFI? And regarding the towing rating, is there any getting around that?

 

The twisted wedge intake is an EFI intake.
I believe the one Conaski is talking about is an upper and lower but not sure.


Regarding the towing only one way to get around that. Get another truck to tow the 40ft trailer and a truck that is rated at that. To my knowledge you can't change towing capacities.
Trav

 

OK, first off the 40 foot trailer is a pipe dream. I just want to be able to tow whatever camper I decide to buy. I see all kind of big campers in the campgrounds that come in on f 250's, 350's etc...etc... I have a XLT Lariat which is a 3/4 HD rated at 8,900. I didn't expect to be told I could not tow a big camper with my f 250. I'm hoping to purchase a 37 footer however that may very well be determined by the outcome of this project. But first thing's first; I gotta build a motor or buy a crate that gets me started. So a twisted wedge intake, a 351 block (possibly a 400 with 351 heads)?????? I appreciate the input.....

 

not a 400 with 351 heads. What you would be doing is stroking the engine (google stroker engine and you should be able to understand if you don't already) using your 351 block (unless you want roller cam which you are going to need a 94+ truck 351 as a base plus the twisted wedge intake. Stroking the engine does get a little complex so if you go this route I would do lot and lots of research.




Otherwise you go simple and you put the twisted wedge intake on, a good set of heads, keep your stock 351 block but all new parts (unless crank and connecting rods are in good shape), a good hydraulic flat tappet cam that is speed density friendly, and whatever else you may need for your 350hp engine build.
Trav

 

Also on that a 302 bored .040 over is around a 307 or 308 something like that

a 347 stroker replaces the crankshaft to give it a longer stroke in turn more torque you can have stock bore but most go with .030 over while they're in there

you have to get the block clearanced for a stroker crank so the rods don't hit the cylinder