Hi everyone im new to the site, i have a 1970 f100 sport custom with a 360 in it. I dont know how many times the odo has rolled over but im thinking its got around 250k on it. Its seems to be running good but has its problems here and there. Im trying to decide if i should replace the engine with something new or rebuild the old 360. Theres so many options of what i could do but i dont know whats best for me. Im not looking for a race truck just something with good power if i need it and mostly just cruising around, daily driving and freeway cruising (its an auto btw). Should i stroke it to 390, 410, or the survival motorsports 445? or should i just take the 360 down to the block and replace everything new? Opinions from the pros much appreciated and any help as well!

Thanks for reading, looking forward to responses!

 

Generally speaking, a 9.5 CR 390 with a properly tuned 600 CFM 4bbl and headers, with an RV type cam will use about the same amount of gas as the 360 and give almost 100 more HP in the process. Not a race motor, just "corrects" a few power-robbing, fuel economy killing features of the 360.

 

cost to rebuild 360 will be same as a mild build of a 390
so i say keep driving the 360 while building a 390 (what i did)
find a donor 390 late 60s tbirds are a great donor for the engine .

 

Ditto.

If you can have the truck down for a while, rebuild the 360 into a 390, or get another 360/390 rebuilt and swap it in.

 

There isn't a damn thing wrong with a 360 and they can be built to make good power which is mainly usually the same stuff you would do to a 390 u can do to a 360. bump the compression slap a decent cam, intake, carb and ignition in and you can get by with out having to source basically another engine. Now if you have all the 390 stuff to do then by all means 30 extra cubes are always nice. But alot of people just push the 360 because they "think" it's a turd remember it's really just a bored out 352. The last 360 I built ran like a champ and I was very pleased had lots of power beats lots and lots of "bigger engines" and the reason I built it was at the time I didn't have enuf extra parts laying around to convert it nor did I have the money for a stroker kit (although I really want one!)
All I'm really trying to say is don't chuck it to the curb just because they never put one a mustang I believe for what your wanting to do a mild 360 would be just fine and I always like the look on peoples faces when they ask is that a 390? Nope you just got beat by a little ole 360!!

 

cool, so how are you raising the compression on that 360?

 

Well one way and probably the best since your doing a rebuild anyway, is with a new piston and since there is a variety off the shelf 390 pistons. Or deck the block shave the heads or set of small chamber heads I know they are kinda hard to find but they do exist of course I'm not good at remembering part numbers.

I'm current wanting to build a poor man's stroker 390 crank 360 rods and I have a set of forged pistons that I plan on shaving a little off of. But this particular engine I'm looking for a little higher than normal compression around 12.1 or so not sure haven't ran the numbers.

Just my two cents I'm sure some will disagree.

 

You should do a little more research.

--no easy solution to 360 compression exists. The 360 uses a 390 piston, but due to the shorter stroke and in spite of the longer rod, the piston ends up over .100 down the hole.

--small chamber heads are early '60s items. They exist, but good luck finding them.

--360 rods on a 390 crank are not a desired fix. You can gain almost a point of CR in a truck 390 using the longer rod along with the short piston used, but that is an imperfect solution.

--12.1 compression? Do you have access to race gas at a reasonable price.

360 rods in a pu 390 real life example:

https://www.ford-trucks.com/forums/1...r-360-a-2.html

 

Maybe you should do some research instead of trying to make me look dumb.

The 360 does use a 390 piston and there are high compression pistons available. Also decking a block or shaving heads to raise compression happens every day, I'm not saying its the best practice but it is a easy way. So what I said is true

Yes like I said the heads do exist and are an option and as I stated they are hard to find. And you never know what you might find in a day at the junkyard.So what I said is true

I didn't say that 390 crank with 360 rods was a viable "fix" but it is easily doable if you have the spare part's and I believe you can even use a factory piston. So what I said is true

I run propane which has an octane rating usually from 103 to 108 (depending on where you live) and costs me about $1.86/gal delivered. So I do have accress to a high compression friendly fuel. So yes I guess that is also true.

Why attack me? We appently both have knowlage of FE motors but some reason you felt the need to call me out?

 

I didnt see his post as CALLING YOU OUT, I did see your post as lacking homework. You cannot shave the heads and deck the block enough to gain any real help without also shaving the intake/head intake face. The geometry gets all screwed up and he ends up with a serious mathematically sick equation. At 45.00 a face thats 360.00 and the stroke (heart of torque is still at ground zero) and quench not where you would prefer it had you opened your wallet that far. JM2¢

And I'm not attacking you!! just stating my opinion. And yes I know the old rule on those..


Isn't propane requiring around 16.1 ?
2nd ? Seriously how is your mileage on propane, Ive seen one truck that was setup for dual fuel which I guess answers my 1st ? But it was a real turd 73 F250 owned by a couple of inbreads. It ran, but barely...

 

Well there are many ways to raise compression was the only point I as trying to make and as you stated decking a block or milling heads can have its draw backs. But it is doable and happens probably more than it should. I had a machinist one time screw up a set of fresh rebuilds for me and I was poor so I was forced into running them fitment sucked but what sucked more was paying for the 100ll av gas to keep it from pinging! (sure ran hard tho)

I guess I got a little defensive I just get tired of everyone giving up on the poor 360's There are viable options that won't break the bank or cost anymore than reworking a 390. Plus I kinda like keeping original engines in place even if they have been warmed over. If it is the original. But if a person is set on more cubes then by all means go big! Love a nasty sounding FE really have there own sound!

There can be a lot of debate on the power output of propane so I'm going to give you my personal experience. It's awesome lol I really do like it the vehicles I have it on it's nice you can walk away from them for months on end come out turn the key and vroom fresh high octane fuel! I do believe that every engine responds a little different and c/r plays a big role I think a person can safely run up to 13.5 to 1 on a street engine but I never wanted to go that high because well if I ever wanna throw a carb on it I can get by with CAM2 or something of the like.
I have had engines that run way better with more power on LPG and some about the same or a little less power. Usually about the same. But you do use a little more I'd say 10% more? Kind of a guesstimate. Low compression engines say 8-1 will run quite well on LPG but it is nice if a person can up that any. One instance that comes to mind back in the day when many farm tractors ran LPG the engine in the tractor had two different head options one for regular gas and one for LPG same thing just smaller chamber for higher comp. Which those LPG heads are popular for guys making a pulling tractor running on race fuel. My favorite part is how far you can "lug" the engine way way down farther than I have been able to on any fuel like 400rpm under load! and smash the throttle no cough just away u go!
But there are draw backs too big ole propane tank to try and hide fittings can be expensive hose is expensive but once you get it installed you don't have to mess with it much. An experienced person needs to do the refills and servicing.

 

its your money your going to spend on it . The more you want to change the more $$ & questions your going to ask . I would rebuild the 360 , ad some hard valve seats if it does not have them already . The stock 360 is a very durable daily driver although likes its fuel .

If your going to mess with engine compression your going to run into timing issues , engine knock and ping , and the poor quality gasoline unless you are filling up with premium gasoline and can find it .

 

Wrong. Bore it .010 over (assuming you have a stock bore now) and get .060 over 352 pistons. It should bring your compression up around 9:1.


Yes you should.

 

Ok I am getting ready to rebuild my 360. How hard is it to make it a 390? Can I just buy a complete rebuild kit for a 390 and put it in crank rods pistons? They are both the same block and head right? So wouldn't that be the best and easiest way?

 

Can you provide a link to .060 352 pistons? How many FE blocks of this vintage have you been able to clean up with only a .010 bore? I'm doing research and you would seem to know. Thanks.