Ok so first and foremost I'm going to admit I'm a total newbie. I've never really torn into engines before done the normal stuff as far as maintenance and changed alternators and stuff like that but never really modified anything. I have a 1991 f350 2wd cab and chassis 5 speed 351w efi with 38000 original miles. I want to get a little more preformance out of it. I think I have realistic aspirations of 300 hp and 350-400 tq. From everything I've read on here so far seems to be start with long tube headers full exhaust and cam upgrade. The question is which cam and all the headers I find for it say without egr or not for f350 so what do I do. Probably been addressed a thousand time but I've searched alot and can't seem to find a good answer thank in advance for any response

 

Longtubes have clearance issues on HD trucks that are 4wd but should be fine on a 2wd. The Crane 444232 is the cam to use.

 

Thank you but what about the egr and air injection issue with long tubes. Is there a way around that without deleting them. Sorry for so many questions but like I said total newbie here lol

 

You should really look into the gt-40 heads for the 351. They are bolt on but you would need a machine shop to drill out the head bolts to fit the larger 351w headbolts.

the heads plus new springs for them are a fantastic upgrade to match long tube headers, a friend and I did it about 3 months ago and it took his dog of a truck into a different category and he claims to get better mpgs by 2-3.

 

Forgot to mention this truck is my tow rig and only every now and then so mpg aren't a worry but I would like it to run smooth no chopy idle or any thing like that. I had planned on looking in to the gt40 heads just wasn't sure what all is involved with that swap. Definitely have to do the thing budget friendly but I also understand sometimes it's better to spend the money on good quality rather than junk

 

Yes and along the lines of that reasoning if this is a rig for towing I'd say forget the 351, it's not worth investing in. You'll never get good bang for the buck HP out of it, it's just too small. Spend $300 on headers, IDK what $800 on GT40 heads, more on this, more on that, next thing you know you've spent $1500 bucks and still just have a 351 that barely does what you ask it and is straining to do it. An IDI or 460 swap can be very cost effective and get you the torque you need.

Along the same lines ask yourself is this really the truck to be investing in. Maybe it's exactly what you need, maybe it isn't, IDK. But you say it's your tow rig, also it sounds like a stripy base model, 2wd, probably regular cab etc. Is it really a good idea to be sinking money into it when that money could get you a better platform to begin with.

I'm not trying to be a downer here, just a lot of people get all gung-ho on what they have and they're ideas for it without really considering those ideas vs. other more practical options.

 

Well when I say tow rig it's not really going to be towing that much just a gooseneck with 2 side x side and a couple of 4 wheelers so about 5000 pounds plus trailer weight. Yes it is your basic version single cab but the thing is my grandfather bought it brand new in 91 and has had it ever since I learned to drive a manual in it so it has alot of sentimental value to me that's also why I won't swap enines. I agree it would be easier to swap the engine to get great power but if I can get it to 300 hp and 350-400 tq I'll be happy with that. Honestly I could probably go less than that really but I figured that would be my goal to achieve for.

 

The heads and a proper intake and exhaust will get you to the three hundred mark.
I found some gt-40 heads in a junk yard on a 96 explorer for less than a 100 bucks.
Also what is the stock gear ratio in the diff. ?

a problem with putting in a camshaft is that most likely you have speed density setup and it is not a evolving reader like a MAF and It may or may not act up on you.

 

Not sure on the stock gear ratio I will check the crane cam that was suggested earlier I looked it up it says for speed density system. I'm just trying to get a plan together before I jump in full force also still trying to figure out the long tu be header questions of do I have to delete the egr and smog

 

Why not delete it and run a smaller belt.

 

Well I'm probably going to order my cam and headers sometime after Christmas going with the crane 444232 cam. I'm also going to delete the smog stuff haven'tdecided yet about the egr. As far as headers does anybody have any recommendations. I've read that I need to keep the muffler to keep good low end torque but should I keep the cat as well or delete it also. Any suggestions would be appreciated thanks

 

You should look into getting the dynomax VT muffler it is a muffler with a built in "Flap". As You shove more exhaust through the wider it opens to allow for proper flow across all widths of the curve.

and if you do find some gt-40 heads you should definitely look into getting a set of upgraded springs.


putting just a cam in will only help so much you really want your whole system to match and flow together. If you put a cam in it with the GT-40 heads and proper intake with the proper exhaust you will then be very pleased with your setup.