I picked up a 74 parts truck for my 67, going to do the front end, and brakes power steering and all that. However my concern is with the 360 thats in the 74. It seems I havnt heard much good about them in the threads I have been reading. The motor I have in the 67 now is a 390 with 352 heads. that motor is pretty much on its last leg. Would I be wasting my time with the 360? I am going to be looking for some power, maybe around 350 horses. Gas milage is some concern, but as this is not a daily driver, I am not going to lose any sleep over it. So should I go for it, or should I find a 390 or something like a 460?

 

If it's a '70's 360, get the "right" timing chain and sprockets - pre '72, right guys? That'll set your cam "straight up" instead of way out of whack for emissions.

Then, get headers and possibly a 4bbl.

You'd be suprised what a 360 can do ...

I used to push my highboy through mud up past the 33" tires in 4LOW and in 3rd w/a 435NP tranny. Mud everywhere, the truck never bogged down for lack of power.

Now a 390, well, what can I say? that's a leap in power...

Why not setup the 360 with headers and 4bbl and maybe the pre-emissions timing set, and then rebuild the 390 as time and money allows? That way, when the 390 is done, you unbolt the headers, carb and intake, remove 360 and insert 390.

 

You got everything from the 390 to make a nice rebuild unless you want to locate 390 rods and crank for the 360. Have you looked into building a 410 for your torque needs? Depends on how the truck will be used.
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You have most of the good parts to build a good motor. You have the 390 crank and rods. The 360 and 390 share the same block, but the crank on the 360 is 3.5" stroke and the 390 is 3.784" stroke. The rods are different, 360 rods are 6.54" where the 390 rods are 6.488". The 390 rods are stronger.

I would take the heads from the 360, and what ever other parts you need. Take the crank and rods from the 390. Then, use both motors to build one good motor.

Based on your priorities, here's my suggested build:
1. 390 crank, rods. Use whichever block is in better condition, you'll have to get whichever one you use bored oversize anyway.
2. Stock 4 barrel intake if you have one, if you dont have one go to the junkyard and get one. If you want to save weight, get an Edelbrock Performer RPM. If you go the RPM route you'll have to match the intake ports to it.
3. Clean up your ports. FE's respond well to this. Smooth things out, clean up the bowls, polish the exhaust. It takes time but if you want to get more than 350hp out of this thing it's kind of necessary.
4. Crane 343901 cam
5. Keith Black #KB150 pistons
6. .020" thick Mr. Gasket head gasket. This is necessary for good quench, which the KB pistons are designed for, and to keep the compression up.
7. Headers. This is a must if you want more than 350hp. The stock manifolds absolutely suck. Go ahead and run mufflers, that's how I'll run the simulations below.
8. I highly recommend an adjustable valvetrain. The cheap way to do this is to go down to Napa, and buy a set of adjustable rocker arms. Then, get the matching 9.157" ball / cup pushrods. This lets you accurately set lifter preload.
9. Holley 600cfm vacuum secondary carburetor.

I think that about covers it. I'll run this through my engine simulation program, Desktop Dyno 2000. The above build will result in 9:1 compression, 358hp @ 5000rpm, and 427ft-lbs @ 3500rpm. The torque curve is extremely flat. If you want more power and slightly less efficiency, you could change the pistons to TRW / Speed Pro L2291's for 9.83:1 compression, and change the cam to the Crane 343941 for 394hp @ 5500rpm, and 430ft-lbs @ 4000rpm.

Edit: 2 posts while I was typing that up. LOL!

 

The problem with the 390 is the oil pump went and I am not sure how much damage has been done to the motor until I tear into it. It still starts, but runs horribly and makes all kinds of ungodly noises. Thats why I was wondering about a straight 360 rebuild. If the bearings are spun and there is damage to the crank, is it cheaper to fix that crank or just get a new one? And also is it possible to get 350 hp out of a straight 360? I ask this because a lot of the threads I read say this motor does not have much power.

 

That 360 is a mule vs a 390 quarter horse, (a 427 quarter horse) why fart around with the 360? even with a replacement 390 crank (cheap) you'll be ahead in power and torque.
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Well, you could make the 360 run great and keep up with the 390. It'd work great. But here's the thing...

Pistons aren't available for it to get decent compression in a 360. This has been hashed and rehashed on this board since time immemorial. Good pistons are, however, available for the 390. Now, it is possible to get the appropriate pistons for a 360 by ordering custom pistons. But it's much cheaper to use a 390 crank and rods, and off the shelf pistons. Plus, the 390 rods are somewhat stronger. This is why nobody farts around with the 360. Now if some piston manufacturer sold some pistons to get good compression in a 360, that situation would change in about 1/10th of a second, and they'd sell the **** out of 'em. But they dont, so we convert 'em to 390's.

I still think you should take the crank and rods out of that 390. A crank can withstand quite a bit of abuse and still be usable. You might have to get the journals ground .020" or .030", maybe farther, but it should clean up. If a bearing spun you might need a new rod, but it sure beats buying a full set! On the crank, I'd rather use a freshly ground crank at .030" under than use a questionable used crank that might be tapered, worn, or out of round. You could have said crank reground, but there again... you've already got one that needs reground!

I say, take it apart and see what you've got. Dont write it off just because it makes noise.

 

Yep I think like said above....first off take the motor apart and see what you going to have to work with...and what parts maybe questionable and may be able to be Machined and brought back into service!!

Only at that point will you be able to make a decision on which way to go that would meet you Hp and Tq goals and be the least expensive!! JMO!!

Russ

 

Trusty Rusty....... What heads were you thinking were on "this" 360 he has? I was going to go with a similar build, but with D2TEA heads. Also, should a guy step up with bigger valves in the heads, or does the power difference not wiegh the cost over bigger valves? Also, just to clarify, this was with the stock intake, not the RPM right?

Sorry.....back on topic folks.

 

Well I have to interject a moment.. I would have to guess the 360 heads are the D2T variety, and they are good heads to use, but I would like to know what the casting numbers of the 352 heads are and if they have been rebuilt before I would recommend which to use... The mid-60's 352 head could be a better choice, depending of course.

Oh yea, don't for get that if you change engine families (to a 460) you will also need to get a different tranny (or bellhousing/clutch setup).
--Mike

 

Yes, I'm assuming he has D2TE-AA heads on his 360, since it's a 1974. It might prove interesting to see what heads he has on the 390. However, if they're 352 heads they wont have hardened exhaust valve seats, so that will add to the cost of the rebuild. Also, he says the 390 is pretty well shot, so the heads probably aren't in too good of shape either. But the point is, there are some possibilities there if he's willing to spend the extra money.

So we need the numbers off the heads. Look between the middle two spark plugs.

Also, my simulation doesn't differentiate between dual plane intake manifolds. It's been said on this board that the stock 4 barrel flows somewhat better than the Edelbrock Performer, and the Performer RPM flows better than the stock 4 barrel. The Dyno 2000 software is supposed to simulate a regular dual plane like the Edelbrock Performer; the Performer RPM will probably raise the numbers slightly due to it's abnormally large ports.

I cant think of everything all the time!

 

rustyf100, a while back I got a F427 intake and installed it on a friends 410 as he had a Performer RPM intake, the F427 made more low to mid torque with very little loss top end. For general street manners it performed better unless normal driving is 4 to 5,500 rpm's. Yes I got it back and on my 414. No time to play but want to try the Sidewinder hanging on the wall next.
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