I am looking for advice. This may be a little long, so I will apologize in advance.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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I have a 1982 F100
300 engine
T18 transmission
9” rear with 3.00:1 gears
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I love the 300. I love the T18 transmission. I just don’t love the 300 and the T18 together in the same truck. The problem is that the T18 had really big jumps in ratio, especially between 2<SUP>nd</SUP> and 3<SUP>rd</SUP>. With the 300 running out of breath at 3000 RMP, the shift from 2 to 3 is a bear. Just going up a modest incline with no load it is hard to get from 2<SUP>nd</SUP> to 3<SUP>rd</SUP> and get back on the power before the truck slows down so much that 3<SUP>rd</SUP> gear puts me too low in the torque curve to pull the hill. Put a load behind the truck and things get a lot worse.
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So, I am thinking about ways to solve this problem. I am thinking about the following options, not in any particular order:
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• Change to a ZF 5 speed and a 4.10:1 rear. This may help some with pulling loads, but the ZF still has some pretty wide jumps in ratio. I am not sure that I would be significantly better off than with the T18.

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• Replace the 300 with a 351W. While the 351W probably won’t have the raw torque that the 300 has, it will have a broader torque curve which would go nicely with the T18 ratios. This would require new engine mount perches, new radiator, etc. Not a big deal.

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• Keep the 300 but switch to an automatic transmission. Either a C4 with my existing rear (or maybe change to 3.55:1) or an AOD with 4.10:1 rear.

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• Keep the 300 and invest in some parts that might broaden the torque curve some. Like headers or EFI manifolds, dual exhaust, Offy C or DP intake, small 4 BBL carb. The drawback here is that if I invest in all of these parts and I still can’t comfortably pull loads, then I have wasted a lot of money.

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I use the truck mainly for pleasure driving. It is not a work truck or a daily driver. However, I sometimes want to pull loads (a 5000 pound car/trailer). Anyone have any input of the above options, or a different suggestion?

Thanks,
Jim

 

find a RUG from a jeep - close ratio 4speed. then 3:1 rear will be adequate.

 

I think any one of the ideas you had would work, although for your first idea(5spd swap) I think it would be more economically feasible to go with a M5OD 5spd instead of the ZF. It will be cheaper, easier to find and more than adequate for your occasional towing needs. Whatever you choose to do has been done by someone here and you'll get plenty of help either way. If money wasn't as object, I swap in the 351 and a 5spd.

Good luck,
The Cracker.

 

Same here. Go for the whole enchilada! Or do what i did and do te new engine first, then as budget permits, find a 5 spd tranny. Not sure what's better - the famed ZF or the M5OD....... Does either trans require a driveshaft change from the 300/T18 setup?

 

I haven't seen a 2wd ZF yet to know. I used the newer t-case with my ZF swap and I did have to change them since the old NP208 was a fixed yoke output and the BW1356 was a slip yoke. I do remember the 2wd M5OD in my old 95 F-150 was a slip yoke.

 

Thanks for the input everyone. I will look into availability of the M5OD. Reading what has been said, I think I will try to find a 351W AND an M5OD :-) I think I could make the 300 work OK, but I suspect that I will never be happy with it as a tow engine with a manual trans, unless I could find a close ratio 5 speed, which was never made as far as I know.

Sorry about all of the "tongue out" faces and ">" in the post. I wrote it first in MS Word and did a cut and paste. It was clean in the preview, then when I posted it had a bunch of > in it. Then I came back a while later and it had a tongue out face next to each >. Not sure what happened, but I will not use Word again.

Thanks again.

 

Hey Sycostang67, I can't believe you're helping him, didn't you read his signature??? I enjoy the humor on here sometimes, it's all in good fun. I'll bet Sycostang67 probably did see it and helped because he's one of the more respectful members here IMO .

 

Yeah I saw it, I dont like to prejudge people though. Besides, I'm a redneck with a tiny pecker so it didn't bother me too much.

 

The 300 will run out of steam at 3200RPM by design with 122 horsepower.

Your torque curve is well below that RPM. 238Ft-lbs to 257Ft-lbs at 1200-1400 RPM.

By the numbers, it's a great towing and work engine, but not one that will get you there in a hurry. anything above 1500, and your torque flies out the window.

The 351 give you about 20 more horses at 3400 RPM, and it's torque curve will be in the range of 251-262Ft-Lbs at 1600-2400RPM.

Both engines are quite capable of doing the Job, the 351 will get you there faster. Quite a bit faster infact.

Ford recomends the 351 with automatic, for 5000lbs towing, when using a 3.00 rear end.

If you put 3.50's in your truck, with the 300 motor, it will pull that 5000lbs trailer very well. Just expect 35 to 40 mph going up the hills.

 

i have a 85 f-150 np435 4sp and a 300/6 i loved the set up but when the engine went i looked all over for someting better now that i have a 351 ho same tranny i love my truck it will hual all i can put on it and pull everything under the sun that i need it to mpg mid 13s sucks but getting some where with a load dont take forever now go with the 351 swap its easy and still a great set up

 

Thanks for the additional input. I am not so worried about pulling the trailer up hill at 40 MPH. I am more concerned about pulling the trailer up hill and being stuck in 2nd because I just can't make the jump to 3rd gear. You have all given me some good info to think about.

As for the signature, it was not my intention to offend anyone. I'm glad Sycostang67 has a sense of humor and did not take in personally. There is a guy in my neighborhood who has dual 6" chrome exhaust stacks on his Nissan mini-pickup truck to complement his 1.8L (or whatever it is) rice burner. It sounds every bit as stupid as it looks :-) I just can't see a pickup truck with exhaust stacks on it and not think of this Nissan. But to each his own.

Thanks for all of the help.

 

I've also been looking at transmission options.
My F250 (351W) has an AOD transmission & 3.54 rear axle. A manual trans would suit my work far better.

But the common Ford version NP435 (NP435E) has those same big gaps as a T18, causing the same problems, particularly in a hilly area like where I am. The Borg Warner transmissions didn't come here in these models.

However of the 4 or 5 models of New Process transmissions, the one used in GM trucks, the NP435D, has a close-ratio gear set & smaller gaps than even the close-ratio version T18/T19s, giving four usable road gears.
It also has the same input shaft splining, shaft length, bearing tube, bellhousing bolt pattern & cap diameter as the Ford version.

The wide-ratio T18 gears are -

1st 6.32:1
2nd 3.09:1
3rd 1.69:1
4th 1.00:1

The NP435D ratios are -

1st 4.9:1
2nd 2.29:1
3rd 1.19:1
4th 1.00:1

First gear is low enough for heavy starts, & a good spread of the other gears.

With your 3.00 rear, this might be a simple-fit option that still gives you good top & bottom speeds , & eliminates the gaps. 1st is still non-synchro.

 

Whoa, I like stacks and all but thats just wrong. We have guy around here driving an old Isuzu pup with 2" stacks, but at least it has a little diesel engine. Can I assume this nissan makes the loud ricey farting noise but on a much grander scale.

 

I think I would change the rear end by tweaking to around a 3.50. You'll get more torque when you shift to 3rd, and this is probably the cheapest fix. On the other hand, a five speed will give you the highway fuel milage when not towing.