It has a 360.But I would like to make it a 390 I was told that if I put 390 Rods and crank that it would be a 390.Is this true?What other things should I do to the motor for sled pulling?Also im not very knowledgeable about this.Should I do anything to the axles and driveshaft or anything else?

 

First, since this is an engine forum, you might want to ask about the rest of the drivetrain in the 73-79 truck forum.

That said, you'd be surprised what a 360 can do in 4x4LOW.

Using the 390 crank and rods with 360 pistons will up the compression a bit, and be a decent upgrade. But with that comes a lot of other work that while you're in there, you might as well just rebuild the engine completely if you want to "work" it that hard.

The rest of the guys will be along shortly to help out (or criticize)

 

I agree a 360 will surprise you in 4wd low. If it was me I'd put a cam in it and headers and a new intake if you haven't already and run it that way. Keep it reliable and it will last longer generally speaking. Keep in mind your rpms will be around 4000-5000 so your cam and intake need to be up there as well.

A tip for pulling is stick it in 4lo and find what gear puts you at about 30-35 mph wheel speed. Tire pressure will be good around 10-15 psi as well.

 

Ok, i'll start off.

If your planning on doing this as a 1 time thing, just go run it. i will tell you tho, don't try to pick a gear for 30mph wheel speed. It will NOT happen. depending on what gears you do have, most likely you will be pulling in low 1st because the jump on the old 4 speeds into 2nd gear even in low range is a big jump.

If you are going to continue to pull, your best bet is to check your rules for the class you will be pulling in, and build to/over the grey area of the rules.

You will find that in the lower classes it comes down to setup, not so much HP. Hitch height, rear springs, tire pressure, finding the right line on the track. I doubt you will have to worry about driveshafts, the only time you should have a problem is if your springs allow the rear or front axles to change angle and thats when it will start to tear stuff up.


Back to the engine. I would just do suspension setup and learn to pull for this year, while saving up to build an engine for the next year. Now there is nothing wrong with chainge carbs, intakes, or easy cheaper stuff as you go through the year. But try to beat guys with driving and setup, then when you have the power you will humiliate them.
When do you build it take your time and do it right, have the quench set properly, and pick the right cam. Don't pick for sound, pick for the RPM you will be runing it in. Thats why its kinda hard to toss together a truck not knowing what gear/engine combo without chainging a little at a time.

If you PM me your email addy, I have a excel spreadsheet that you can alter tire size and gears and it will give you RPM vs wheel speed.


And also remember looks doesn't win truck pulls.

AND DO NOT DO THIS
This is my g/f learning to pull. She got a little happy on the clutch. This is with a 360 in a 79 f150
Bria Small block showroom Grantsville 2011 - YouTube

Same truck Little better pull out
Bria Listie june 25th 2011. - YouTube

Same only with me driving and the first hook with the 390 2nd place
Small block showroom Mcconnellsburg orlo - YouTube

somerset county fair 2011 small block showroom - YouTube

Now in all of the vids did you notice how the front of the truck picks up, you need to avoid thats as much as possible, the more level the truck is coming down the track, the better it will pull. I have a bunch of changes to do to the setup of her truck this year, I just didn't have the time last year and wasn't so worried since she was learning to pull and drive a standard at the same time.


and just for fun, my truck. 1st place

Listie june 25th 2011 Street diesel 1st place - YouTube