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I know Mr. Paul "Conanski" is the guru so I spent a few hours researching. Wow this was lot of fun! Here's what I found. Below this is where I ask for confirmation before I purchase parts and mod my truck. Thanks for your patience, and a big thanks to Conanski for his contributions to us all.
This is for the 1991 F150 XLT Lariat 4x4 RCSB Red & White 351 E4OD 3:55
==================================== https://www.ford-trucks.com/forums/1...l#post16726416
Yeah... you are totally wasting your time and money with all that stuff if you don't change the cam, the cam to use is the Crane 444232.
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Paul (Conan) O'Brien
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https://www.ford-trucks.com/forums/1...be-owners.html
So I'm going to be installing my long tube headers tomorrow, while I'm at work I'm gonna weld my bungs on the headers for my o2 sensors. Where should I install them? Just right at the collector on the inside that faces the transmission? is there any clearance issue putting them there?
I think you'll find that something like 5:30(DS) and 7:30(PS) will work better because when the headers are installed they sit on angle and you don't want the sensors perfectly horizontal pointed at the trans you want them angled down a little to clear the trans lines.
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Paul (Conan) O'Brien
I'd strongly suggest upgrading the heads to some late model('87+) E7TE or better yet some F1ZE(91) or F3ZE(93) GT40 heads off an early V8 Explorer 5.0. Both of these options will give the motor a 1/2 point bump in compression and in the case of the GT40s significantly improve airflow which will boost both torque and Hp output. Any cam in the 250-260 deg advertised duration range will work well here and produce a stout powerband from 0-4500rpm give or take.
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Paul (Conan) O'Brien
Nothing but stock parts needed in the shortblock to have a reliable motor but if you have bent any con rods replace them for sure and select pistons with valve eyebrows to guarantee valve clearance. The Crane 444232 cam and lifters kit is what I always suggest for these early 5.8s, it's a nice step up from stock and will play nice with the EFI system, and there is room for 1.7 roller rockers as long as the valve springs can handle close to 0.500" lift. The Typhoon intake takes a 70mm throttlebody so that's what you should get, and there's no need for anything except the stock distributor so use it if it's in good shape.
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Paul (Conan) O'Brien
Post #28
You can't put an X pipe on a 4wd truck, you can't put any kind of balanced dual exhaust on it because the transfer case and front gas tank are in the way.. it's all got to go down the passenger side. So my suggestion is get a Magnaflow 2-into 1 collector and build a complete 2.5" single system with mendrel bent tubing. And if you want to maximize gains at low rpms longtube headers would be the better choice.
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Paul (Conan) O'Brien
The stock cam in this motor is pretty good with 256/266 advertised duration and 0.422/0.448" lift, for a little more area under the curve add 1.7 rockers.
If you want as much low rpm power as possible you need to ditch all of the stock exhaust and then add longtubes and a single 2.5" exhaust, shorties with stock plumbing behind it is a complete waste of your time with zero gains.
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Paul (Conan) O'Brien
07-28-2013, 11:25 AM
Shorties are an upgrade over manifolds if the stock Y-pipe and cats are replaced with something(anything) from the aftermarket. Pacesetter longtubes are the best fitting available for these trucks but only if it has a TTB front axle, if it has a solid use the shorties.
For low rpm power the replacement cam to use is the Comp 35-512-8, but this cam with 1.6 rockers is almost identical in lift and duration to the stock cam with 1.7 rockers so you won't see much gain for the money spent.
No machine work involved in adding roller rockers as long as you get the pedestal mount version, these are available in both 1.6(stock) and 1.7 ratio for these motors.
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Paul (Conan) O'Brien
You can't use that cam unfortunately because of the EFI system, it requires cams with at least 114 deg LSA and no more than 210deg intake duration at 0.050" lift, and besides that it's a flat tappet cam and you already have a roller setup. The cam to use for max torque is the Comp 35-512-8, add longtube headers and a single 2.5" exhaust system with GT40 heads that are milled a little to bump compression to 9.3-9.5:1 which equals about 60cc chambers(stock is 64cc).
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Paul (Conan) O'Brien
Quote:
Originally Posted by gear_head28 View Post
I've read that if i do a cam I'm supposed to go with the same rockers (1.7)?
No it's not a requirement but of you do use 1.6 ratio.
Quote:
Originally Posted by gear_head28 View Post
If I do that, will i have to have longer rods
Pushrods? No.
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Paul (Conan) O'Brien
That looks like a good spring kit, I was gonna say you want to make sure you get the correct retainers for whatever springs you use but it looks like they have taken care of it for you. This kit will let you upgrade to 1.7 rockers too if you feel the need.. tough these heads don't flow any more past 0.500" lift so there's not much point in poking the valve open more than that.
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Paul (Conan) O'Brien
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Here's where I get schooled!
Quote:
Originally Posted by 87-XL-Squared View Post
You have a speed density computer system. The computer won't recognize performance mods, it runs its program, the way its programmed.
This was a common misconception years ago and frankly I'm surprised people still believe it. The EFI systems in these trucks do not control the engine per se they feed it just like a carb, the system does not in any way restrict power output it's actually designed to make as much power as the engine combination is capable of generating. So making more power is simply a matter of upgrading the components in or on the engine that are holding it back and then the EFI system will attempt to keep up. It is true that the MAF system is much better at keeping up but even the SD system can adapt to some bolt on upgrades as long as you don't get too carried away. In this case the restrictive engine components are the camshaft primaraly and to a lesser extent the exhaust and cylinder heads.
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Paul (Conan) O'Brien
1. It appears the '91 I have is not roller. The later models are roller and use the Comp Cams 35-512-8. The cam for my motor is the Crane 444232. Please confirm.
2. My F150 4x4 is a TTB and will accept the PaceSetter Long Tube Headers 70-2223. They offer a ceramic coated version for another $200 but one review on Amazon says it didn't hold up and rusted out. Please confirm this header choice and what is your recommendation on the ceramic coating - would you spend the additional money which means $500 instead of $300?
3. The previous owner retained the factory manifolds and crossover with the single O2 sensor then went dual exhaust to two mufflers. They eliminated the factory cats. From what I've read in the above threads I need to install long tube headers into a single exhaust. Please explain the best method, one muffler or two, etc. Clarify the exhaust architecture for me.
Please note that Conanski says in a post above: https://www.ford-trucks.com/forums/1...351-build.html
You can't put an X pipe on a 4wd truck, you can't put any kind of balanced dual exhaust on it because the transfer case and front gas tank are in the way.. it's all got to go down the passenger side. So my suggestion is get a Magnaflow 2-into 1 collector and build a complete 2.5" single system with mendrel bent tubing. And if you want to maximize gains at low rpms longtube headers would be the better choice.
That's a good compilation of his advice. Paul definitely helped me out in my 351w build, big thanks for that!
I ran 2.5" tube along each side of the trans, with the driver side making two 90 degree turns to cross over just behind the trans mount, and feed into a Y pipe along with the passenger side. The Y is dual 2.5" input, single 3" output, that feeds into a single muffler. For simplicity I just ran a turn down after the muffler, but side exit or full tailpipe is fine too. I ought to run a cat, just don't have one in at this time. No inspection in Wyoming so I can get away with it.
You're correct that your engine should be flat tappet equipped and not roller lifter ready. F4TE casting numbers were roller ready, F means 1990 decade and 4 indicates 4th year of the decade. Roller blocks started in 1994 for the 351w. Either use the flat tappet cam that was recommended (nothing wrong with this), or, you can use a roller cam with link bar lifters in your non roller ready block. Link bar lifters sounded like a waste of money to me initially: however, at that time I was not aware of the high frequency of cracking in the #2 & #4 can bores of roller blocks. Sure enough, my roller donor block was cracked. It didnt show up with magnaflux but it was obvious. I'm running it anyway, because I love a good experiment. 10k miles of hauling snowmobiles and all is okay so far. But, knowing that now, if someone wants to run a roller cam 351w I'll steer them to link bar lifters in a non roller block.
I'm not sure on headers. I went with the Chinese stainless headers off Ebay. They were a chore to make fit. Hopefully you find something that fits better and clears the dang starter.
The roller cams really are worth it...the ramp rates of the lobes are more aggressive.
Flow tech long tubed seem to be the cheapest option that has the least fitment issues; there is plenty of flange bolt clearance, spark plug clearance, and starter clearance. The only thing I've had to do to them is bend the drivers collector to clear 4x4 front shafts.
The later models are roller and use the Comp Cams 35-512-8.
Not quite, the stock F4TE roller cam is similar in duration but doesn't generate as much lift.
Originally Posted by 87-XL-Squared
The cam for my motor is the Crane 444232. Please confirm.
IMO yes.
Originally Posted by 87-XL-Squared
2. My F150 4x4 is a TTB and will accept the PaceSetter Long Tube Headers 70-2223. They offer a ceramic coated version for another $200 but one review on Amazon says it didn't hold up and rusted out. Please confirm this header choice and what is your recommendation on the ceramic coating - would you spend the additional money which means $500 instead of $300?
I had a set of ceramic coated headers on my '90 originally and they held up much better than the painted set that followed which only lasted 2 years.. but I live in the Great Salty North. The ultimate for durability would be stainless.
Originally Posted by 87-XL-Squared
3. The previous owner retained the factory manifolds and crossover with the single O2 sensor then went dual exhaust to two mufflers. They eliminated the factory cats. From what I've read in the above threads I need to install long tube headers into a single exhaust. Please explain the best method, one muffler or two, etc. Clarify the exhaust architecture for me.
I built a couple different systems like this but the pics should give you an idea. I don't see the need for a full dual system on these trucks.. it won't perform any better, if you want the look then just get a SIDO muffler and route pipes out the back over the axle.
03-18-2017, 10:52 PM
