ok, gotta fully stock 360 in my '73 f100 and am getting close to pulling it to make 'er into a 390. I want the most mileage obviously i can get w/ todays prices but i also want alot more power than i'm gettin with my 360 . I was told once that the 360 puts out about 168hp and at 8mpg i'd like more power for that sorry of mileage. Then once i heard a 390 in a '74 supercab with the same tranny and rear end as mine was getting 16mpg i was ! anyways i've gotta $1000 to put towards a 390 build. the 360 i currently have has 5,000 miles on it as a recent rebuild so i know i can just hone the cylinders and that be all that i do to the block. I just have questions when i get to what type of pistons to use, head gasket (mr gasket .020?? felpro?? corteco??) b/c i'm not fully understanding in the "quench" department. Basically what i want is the highest compression i can get to be able to run 87oct w/o having to worry about adjusting my dizzy every 1000 miles or so just to keep the timing dead on. Also my heads are stock ones on the 360 (not sure of the head #) but would getting them cc'd be something i should consider?? My machinist said he could get me the 390 crank and rods for me but i just want to do this right the first time obviously. Right now i'm thinking i'm just gonna get a 390 4brrl intake with a holley 600 vac sec. also i'm not sure of the cam to go with this setup-i want a smooth idler with as much power as possible. I know this all sounds scatter-brained but if you could ask questions i can answer them as far as what i'd like. Thanks for any direction!

 

It's a good thing that the 360 was recently rebuilt, or the machinist would eat up a good portion of that $1000. Still, he will probably want to check for any ridge that may have built up on the cylinders. With only 5000 miles, you'll probably still be able to see the crosshatch pattern on the cylinder walls, and a quick re-hone and it will be good to go.

Pistons: This is good, you already have the correct pistons! Use 'em.

Head gasket: The Fel-Pro is probably the one to go with. KB-Silvolite recommends .040" to .060" quench (distance from piston to cylinder head at TDC). Lots of guys run it tighter than that. With stock 360 pistons in a 390, you'll have somewhere around .012" of deck clearance, added to the .041" compressed thickness of the Fel-Pro, gives you .053" of quench. This is right in the recommended area. Assuming your cylinder heads are 73cc's like my spare set of D2TE-AA's were, you'd wind up with somewhere around 9.3:1 compression. Plenty streetable with the correct cam. But things can and do vary from my numbers, be sure to measure the volume of the combustion chambers, volume of the piston valve reliefs, and deck clearance. Then you can come up with an accurate number for compression.

Cam: The Crane 343941 will work good. It'll bleed off some extra compression and keep the engine streetable on pump gas.

Valvetrain: Go adjustable. From what I've seen on this board, it's just more reliable. I've read too many instances of "I put this aftermarket cam in with my non-adjustable valvetrain, and now I'm bending pushrods!" Ask if you have questions on where to get the parts.

Heads: Although FE heads respond extremely well to porting, for your purposes, I'd just leave 'em alone. The smaller unported ports will help airflow velocity and fuel atomization.

Headers: Kind of a pre-requisite for an FE.

You're right on track with the 390 4V intake and Holley 600 vacuum secondary.

Good luck!

 

so what you're saying is that you wouldn't recomend using my stock rockershaft setup even if i check my rockerarm to valve clearance and use the correct length pushrods? What do you mean by adjustable valvetrain (can you give me a example summit part number to see)? This will be a daily driver and occasional heavy hauler too-forgot to mention that earlier and i don't want to go back inside this thing short of at least 200,000 aside from the normal waterpump/timing chain replacement. Also i've heard talk about a higher volume oil pump. what all would i have to do to my block to get this to work? open up my drain ports to allow the higher amount of pumped oil to drain back just as fast as it's pumped? pistons-all i should have to do is get a new ring set right? thanks for you patience and answers. just trying to make the best decision from guys who've been there dont that!

 

Is this the same machinist you used for the 360 build? Is he putting together the long block or are you? Basically, all you need is the 390 crank and rods, a fresh set of rings/bearings/seals and your ready. Do you have the specs or the number of the cam you put in for the original rebuild? If that was done right, you may even be able to use the current cam you have..... I would not recommend stepping up to the HV oil pump, it's not a necessity. Going with the adjustable valve train is also a nicety, but depending on the cam, you may be able to use your current non-adjustable set up.

--Mike

 

The purpose of the adjustable valvetrain is to get accurate hydraulic lifter preload. This is nearly impossible with a non-adjustable valvetrain, since you use pushrods of different lengths to kind of make up for variances. Aftermarket cams, from what I've read on this forum, seem to aggrivate the problem. My theory is that the base circle of the cam is different between stock cams and aftermarket cams, and people dont take up the difference, leading to bent pushrods and wiped cam lobes.

You dont need new rocker shafts, stands or stand bolts. All you need, is the adjustable rocker arms, and matching pushrods. The Crane rocker arms from Summit look good, part number CRN-34772-16. The stock replacement adjustable rocker arms will probably be just as good, and cheaper. They're not sold on Summit though. You'll have to call around to parts stores and see what you can get them for. They're for a early '60's 390 police interceptor motor, or early 352 with mechanical lifters. Try a 1963. For the pushrods, go to DSC Motorsports and get their "427 Ford Adjustable Pushrods". The "DSC Motorsports" above is a link, click on it, then click on pushrods in the list that comes up. You'll have to call the guy to order 'em though. You'll need new lifters too, you can get those from Summit, part number SUM-HT2083. Dont forget to buy 16 of 'em. You'll probably want new valvesprings too, number CRN-96801-16.

Lets add it up:
Cam, 343941, summit: $109.88
Lifters, summit: $48
Pushrods, DSC: $45
Rocker arms, summit, or locally obtained: $209.88
Valve springs, summit: $91.99

So you're looking at, at most, $505 to convert to an adjustable valvetrain and put a bigger cam in. Now you'll have about the same setup as I have in my motor.

 

rusty- ok so once you set these "adjustable" rockers they stay put till 200,000 right assuming you have the correct length pushrods and all right? how big of a difference are we talking about between stock valvetrain and your setup as far as hp and torque-are there any other advantages to doing it this way? to me it just seems like alot of my $1000 going to one area that i thought was already alright but i could be wrong.

mike- same machinist, all he's doing is gettin me the crank/rods and rings and balancing the rotating assembly. i don't have the part# of my cam handy at the moment but my machinist gave me everything i needed to put my motor back straight stock-not sure if that tells you anything or not. i'd really like to use the valvetrain i've got to save money b/c i'm already lookin at 10-12 mpg ...come on. now if that $500 vavletrain got me 5 more mpg then hock ya i'd do it but who knows. plus i'm 19 and what 19 year old's gonna just putt putt around with a 390 ...not too many unless their really broke for gas money!

thanks for the info fella's...we're gettin there slowly but surely

 

Yep, set 'em once and forget 'em. Hydraulic lifters make up for any wear.

The power is in the cam. It gets the valve open quicker, lifts them higher, holds them open longer, then closes 'em quicker. Theoretically, you COULD make it work just fine with the non-adjustable setup. You would want to check and re-check lifter preload on each and every lifter - a lengthy time consuming process. And if any are too much preload or not enough preload, you need different length pushrods. It's a pain. And if you dont get it right, you just bent pushrods!

Adjustables are much simpler. Crank the adjuster screw until all the slack in the pushrod is taken up (it's snug on the lifter and rocker), then go another turn to preload the lifter. Done.

On my engine, I think the difference would be around 50 to 60 horsepower. Not to mention the fact you need the bigger cam to bleed off some compression so it doesn't ping. The way I see it, if you dont want to run premium, these are your options:

360 pistons and 343941 (or bigger) cam
Stock cam and dished pistons

Either way you spend money.

Edit: Hey, I'm 24, and my 390 gets no special treatment, believe me! With the Holley fuel injection system I've got on it, I can get 15mpg on the highway. It got 17mpg once with a tailwind. Now the fuel injection does help stabilize the mixture, but a well tuned carburetor and distributor should be able to duplicate my results. Plus, there's a 127' black streak left in front of the house, that's STILL burned into the road.

 

i had typed up a post ealier but i have been on to many midget **** sites and my computer froze up.


things needed imo
crank ground
rod big end resized
smallend bushed
arp oil pump shaft
new rod and main bearings
new cam cause melling,clevite, speedpro sucks
new lifters
new springs, not stock either
headers and good gaslets like $30 worth(i like copper on a planed head)
4bbl intake
600cfm carb, electric choke, vac secondaries, no dumper pumper crap.



theres a $1000

if you go with a 941 cam, you may need custom pushrods for the non adjustable rockers. the 901 cam works with stock pushrods and rockers, still requires new springs though.




FTE A.D.D member

 

I am planning on putting a 4 barrel carb on my truck and putting a new distibutor in my 390. Definetly invest in the 390 crank. It should make a whole world of difference.

 

rusty- ok i see you said i could either go the $500 valvetrain way or get dished pistons w/ my stock cam. what if i got that crane cam you said to get w/ dished pistons and the rest be stock valvetrain? we're then looking at 390crank/rods, crane cam, stock valvetrain, dished pistons, 4v intake and carb, .040 felpro head gasket (i guess), and headers. Sound pretty reasonable for an everyday driver/heavy hauler?

also wouldn't my stock pistons be dished right now?? could i just use those with the crane cam? thakns

 

The idea of the valvetrain modifications is to make it so that the valvetrain doesn't take itself apart with the more agressive Crane cam. The pistons have nothing to do with it.

Option 1:
360 pistons are not dished, they have 4 valve reliefs. They will give you a compression ratio high enough in a 390 that you should use a bigger cam, with it's later intake valve closing angle, to bleed off compression at lower rpm's to prevent pinging. The bigger Crane cam lets you get away with the higher compression ratio of the flat top 360 pistons, but the Crane cam requires valvetrain modifications. Well not requires, but strongly recommended.

Option 2:
If you used the stock cam and the 360 pistons in a 390, what you'd have is a small truck cam in what essentially now has become a 390 4V motor. These required premium gas back in the day. With todays craptacular gasoline, you'd ping like crazy. This is why you have to get dished pistons if you intend to use the stock cam. The pistons you want for this situation are Silvolite #1130.

Option 1 will cost more than Option 2. Both options will keep you from pinging and / or blowing the thing up. The choice is yours.

 

Well if only we could offer other members, deals on parts, i could save him 500 or so dollars on a 390.