Hello everyone, I've finished up my 300 swap, and finally had a chance to cruise around this last weekend. Needless to say, I was a bit disappointed. My truck is supremely gutless.

A few things I noticed in my last drive:

== Takes forever to get up to 65mph. Need really flat ground, and a looooong stretch of highway;
== No way I could ever pass anyone. Zero acceleration at highway speeds;
== Not a lot of acceleration when starting. Zero "throw you back in your seat" feeling when you jam the pedal;
== Going up steep hills sucks. Have to down-shift to 3rd gear, and crawl up the hill at 30mph;

For reference, the 300 I swapped into my 76 F100 4x4 has a 240 head/new higher compression pistons/Offenhauser C series intake/1.08 Motorcraft 2100/4-speed NP435. EDIT: Have 3.73 gears and the EFI exhaust/Walker Y-pipe combo, and running 31"x10.5x15 tires.

Is this type of performance mostly "normal" for a 300 engine? It had a stock-ish 390 in it before, and that motor puts the new 300 I swapped in to shame. The 390 could do 60mph up a hill in 4th gear, and my 94 302 f150 could pass vehicles on the highway at 70mph with a bit of revving. Just wondering what "normal" should look like for these old trucks with the 300's in them. Thanks

 

Yes, that sounds about right. I had a 300 with the Clifford intake/headers and a 4 barrel carb. It was significantly better than the stock setup , but I could rarely stay in 4th gear going up an incline. It would get you around, but you won’t get there fast. Might need to look at the gear ratio.

 

240, 300 what ever, neither are a V8. I feel your pain, I had a 2wd 73 with a 240 and 3 on the tree, blew it up. I put in a 300 with the same trans...still a 6 cly. Had L60's on the front and 31x10.50x15.s
Stock gearing, gut less all day long. I eventually blew up the 300...I was 16. And have never owned a 6 cly again for those exact reasons.

Gearing? Maybe a gear change might get you more throw back in the seat, but you will loose the top end then? Tire size? Trans kick down lever adjusted correctly?

 

Thanks for the reply. Tire size is 31x10.5's, and gearing is 3.73's. 4 speed manual, so no kick-down cables.

 

Rats, I was hoping I'd at least have something that could do a steady 60mph and get up to speed somewhat fast.

Oh well, I guess it's just a matter of getting used to what "normal" is for this motor.

 

Don’t get me wrong, it’s a great engine, just was never meant to “put you back in your seat” and will never compare to a v8 in those terms. Mine is 4x4 and the engine is great for off road. I drove the 300 for many years and a lot of highway miles. I’d just plan ahead when it came to hills and get up as much speed as possible before the hill.

But im in the middle of converting to a fuel injected 351. It will be more fun around town and on the highway. But offroad won’t be as good as the 300.

 

Yes some time I read to fast. 4 spd... obviously no kick down rod. Except when you kick the clutch to the floor and grab 3rd. lol

 

Are you running stock exhaust?

 

I was driving along beside my SIL in her '85 Beat to death Toyota 5 speed/4 cylinder. My van was the 300, 4 speed OD, 3.50 gears and 31-10.50 x15s. I laid into it from a couple stop signs, shifting just short of the pistons swapping holes. When we got to Ma's house, I asked her if she had to get on it to stay with me. She said she hadn't noticed.

Part of it that fact that the 300 has a lot of "flywheel" as it is, and when you add more out at the end of the axle shafts, performance really suffers. That and a host of other things.

 

 

Exhaust is EFI manifolds to a Walker y-pipe, connected to a cherry bomb. It's loud and obnoxious, and I'm hoping to swap out the cherry bomb for a proper muffler soon.

 

I/we plan on doing a similar set up (intake, carb, exhaust) on ours. Except for going to a dual outlet muffler for dual exhaust. For the most part, with our stock set up, ours is pretty good. We have 3.50 gearing. We haven't had it up to highway speeds yet as our steering is not trustworthy at the moment. Currently installing a blue top.

I might pick your brain some when we get to intake/exhaust install.

 

I have a 1978 F150 Custom with a stock 300, Carter YF 1bbl carb, 3.25 rear gears, and a 3 speed + OD trans. I can accelerate and cruise on the highway just fine. It's no V8, but I pass people on I635 here in Dallas all the time. And that's like driving on Fury Road!! (WITNESS ME!!!) I would check your gearing, and make sure the carb is set right with no vacuum leaks.

What size carb do you have??

 

You need to re-gear your axles. I would say 4.10's would help a bit. One thing I learned in my years of lifted trucks is that you can add all the exhaust work, carb work, high flow air filters, and what not to an engine, but nothing will give you more pep than putting proper gears in your axles. I always tended to err on the lower side of gears especially if you run a heavy tire/wheel combo. On paper, 3.73's might work, but 4.10's might work better....you'd be surprised how much power a heavy tire eats up.

 

Carb is a 1.08 Motorcraft 2100 2-barrel. Chose it because it's a dead-nuts simple rig, and hopefully would get decent-ish mileage with it. (Truck was built with the "goal" of having it be a super reliable rig, with everything else secondary.)

(WITNESS!! Yeah the way my rig is operating right now, I would be left far, far behind on those battles. But for cruising dirt roads at 35mph, it seems pretty good at that.)