The 360 build that has more turns than Willow Springs

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Kern Dog

Build your car to handle.
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Many of you have dealt with this sort of thing....
You have a car that needs an engine rebuild or swap so you start thinking of what to do. The options may be all over the place and hard to choose.
For me, I have these two cars to work with:

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The black car looks terrible but is as fun as you can have with your pants still on. It currently has a 70s era 360 standard bore but in 2003 or thereabouts it got honed and new rings installed. In 2006 I got it from a friend and put in a MP 280/474 cam and '308 heads. This dude flat out scrams for such a mild build. 360 manifolds, 2 1/4" pipes, a Weiand intake and Holley 750 and boom, it just runs great.
BUT I wanted to step it up a bit. Last year, a buddy pulled this engine from his Valiant:

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This is a 1990 360 from a truck. He rebuilt it back in 2012-2013. It has the desirable Air Gap intake, the '308 heads, a roller cam too!

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He pulled it when he blew a head gasket. Yesterday I tore it down to find the pistons were just .020 over. Smart move, only bore the minimum to allow for future options to bore again later if necessary. Look at those intake ports. The water that went through it also sat in a few cylinders so boring it will now be necessary.
The cam in it is a Hughes hydraulic roller and it specs out at 218/228 duration @ .050 with .544 lift with an RPM range of 1800-6100. That is excellent for a solid street engine. It has these:

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Thicker pushrods too. The man spent some money to build this but once it blew a head gasket, he lost interest in chasing performance so he pulled this one and just swapped in a stock 360.
In regards to the opening comment about a 360 build that has many turns, this engine was almost traded to be built as a stroker 408 for this car owned by a guy named Rich:

68 Dart.png


FABO member RB Convert owns the '68 Dart above. He has one of those Mopar Performance crate 360s in the car, the 380 HP version. He wants to build a bigger and more powerful engine and wants to stick with a roller cam.
I had the thought to trade engines with him....he could use this 1990 block to have the roller cam type block and build the engine over time, then swap them out and I'd keep his engine. It was based on this trade that I started the thread here looking for intake manifold options for a Magnum 5.9/360.

Intake manifold options for a Magnum 5.9/360

Yesterday we tore down the 1990 engine with the intentions of HIM rebuilding it with the 4.0 crank and Trick Flow heads. As we tore it down, he began thinking that it would be a shame to split this engine up.
It would have been fine for me either way....swap and use the Magnum 360 in my Dart or rebuild this 1990 engine for it.
One factor that would sway the final decision was the condition of the bores. If they could clean up the water damage/rust with a basic hone and cleaning, I'd keep it and reuse the Speed Pro pistons it has. If it needed to be bored, maybe he would go ahead and take it.
Well, the machinist did think it would need to go to .030 at least. I thought Rich would reconsider but I think he might have been doing me a favor by suggesting that I keep it. Now I'm going to move ahead and get this dude together for myself.
Using the search feature, I read that this piston is a common choice for 360 builds:

https://www.summitracing.com/parts/uem-kb107ktm-030

These come with rings, pins and retainers for the pins. I won't be spraying nitrous, I won't be drag racing either so this type of piston will be fine for me. Heck....I have stock cast pistons in the 70s 360 that is in the car now and that engine runs great.
You may ask why I am replacing an engine that already runs great?
Here is why....

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Last year I picked up that green 4 door and I want to get it up and running. The 4 door has no engine in it so it needs something. The '67 Dart 70s 360 runs great, it just needs attention to some oil leaks. The 4 door is slated to get the 70s 360 and an A-500 4 speed automatic and 3.55 gears for a sweet cruiser that ought to be pretty peppy when I need it to be. This car will get the engine from the black Dart since it is a proven engine so this opened up the options for building another 360 for the black car.
We often feel the need to "justify" the expenses we have with these hobby cars, don't we?
 
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As regard those KB107s
I have those in my 360, which gets abused every time I fire it up, since 1999.
IMO the ring gap spec of .0065/inch bore, "for street", is too tight. I had an impossible to solve overheating issue, right from day one. The Skirt spec of .0015 to .0020 may be ok, IDK; but my engine builder refused to set it that tight. He gave me .0035
I nursed her thru the first summer, then tore her down.
I had the skirts rubbed out to .0040, and installed a file-fit set of rings at .0080 ring factor on the top, and .0070 on the second. I left the oil ring gaps alone at .0065 spec.
That immediately solved the overheating, but on cold mornings, I could hear the piston slap.
I solved that with a hi-flow 195 stat that actually runs at 205/207 at the stat house, and she is underdriven just a bit.. and, I give her a lil time to come up to temp, before beating on her,
With OOTB Edelbrocks, TTIs, an AG/750DP and at 11/1 Scr with a 230/237/110 cam, car has gone 93 in the Eighth with 3.55s at 900ft at 3457 pounds, me in it; on the only one completed run of four it ever made..
To say I was ecstatic is an understatement.
After I solved the heating issues, I got nothing bad to say about those 107s.
By the way, I have consistently run a Q of .028 to .032 on those, with factory rods, with no touching, with the rev-limiter set to 7200. Currently my pistons average .007 above the deck. They fell in at .012 below. So the total deck-mill is about .019
One Time, I ran 028 gaskets, but they barely made it thru the summer, as on teardown, the fire rings were seen to be almost into the valley. But I admit, I was running about 195psi at the time.
Yes, for the first five or six winters, I pulled that 367 out every fall, and swapped in a 318 for the winter; then freshened the 367, for a May-long install. Four of those winters, I caught stuff that would have cost me a lotta money to fix, if they had matured. Most of the gaskets were reuseable, so mostly it just cost me time.
And I learned an awful lot about what doesn't work. and a lil about what does. For example I reused those 039 Fell-pros a couple of times, and got away with it. I still have one used pair hanging in the rafters..... waiting for a project.
But
Those 107s IIRC are just 502 grams, so, I had to rebalance everything.
I'd have no problem using those again. Mine are plus 040.
 
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Another nice choice for LA style pistons is the H116CP. May want to look a those Mr Kern. They are on my radar. Wish I had your roller block for sure. Great starting point.
 
I have wiped out a few cams. The last one was Summer 2022 and it is strongly suspected to be due to the oil that I used since I ran the engine for years with one type of oil then switched, only to have the cam lose several lobes within a few months.
I hate the anxiety of losing a camshaft. I've decided to swap a roller into my big block in another car and since the last of the LA/Magnum engines already had the roller setup, I see no reason to use a flat tappet block.
The machinist is going to see if the block will clean up going from .020 to .030. He thinks it should. I'm not sure how busy he is so the waiting game starts. I'm looking at either .030 or .040 over pistons but won't order them until I know where the block cleans up.
I wish that I was friends with a dyno operator! It would be great to test the car as is, then test it with the next engine. I have a nice 904 in the car but I don't know if I should trust it to hold up given that this engine should make more power. The roller has more compression, more cam, better intake and I'll use headers and 2 1/2" exhaust. Everything steps up on this one.
I have a nice 727 and a factory high stall converter that I could use, that just means drive shaft and linkage modifications. The axle is an 8 3/4" with a 4.10 SG diff.

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Not to turn this into a transmission thread but I would keep the 904 in a light A body especially since it's a street car. Either way if you need a converter I highly recommend Edge Racing Converters. Andre is a MoPar guy too and great prices on a custom converter.
 
Sometimes the head gaskets tell a story as to what happened. I think these two do.

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Now, I’m not a professional mechanic but I’ve worked on cars as a hobby since the 80s. I’ve seen head gaskets blow between cylinders, I’ve seen them blow to the outside of the lock and into water jackets. What the heck is this ??

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The ring around a few of the cylinders looks egg shaped.

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Incorrect torque during installation ?
That was either 1357 or 2468, I don’t remember but look at the back side, this is the cylinder on the end.

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The oil isn’t the issue, that just dropped onto the gasket after removal. Look at the weird bulge outward.

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I know the guy that built this. He is not a bad guy but it seems everything this guy builds has to come back apart sooner than you’d want. Here you can see where it went to water. The “fire ring” is rusty near the water jacket hole.

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The other side isn’t much better:

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A small part of me wants to blame the gaskets at least a little but what the heck? I’ve never had this happen to anything that I have built. I’ve thrown a rod, wiped out a few cams but never had a blown head gasket like these.
 
I didn’t check the torque of the bolts as I removed the heads. They all made that snap sound as I cracked them loose, it’s not as if they were finger tight. I saw this:


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Note how the hole is off center.
 
Probably just a bad tune. Detonation pushed the gaskets out, I am guessing. Just check the surfaces for flatness with a proper straight edge and feeler gauge before replacing the gaskets.
 
I actually took the block to my machinist.
The blown head gaskets resulted in water sitting in a few cylinders so they will need to be bored to clean them up. I'll have a cursory deck resurface done too. He is going to check the heads far cracks.
 
I actually took the block to my machinist.
The blown head gaskets resulted in water sitting in a few cylinders so they will need to be bored to clean them up. I'll have a cursory deck resurface done too. He is going to check the heads far cracks.
Who'd you take the block too?
 
Very common for detonation to push the gaskets out the intake side. Happens a lot.
 
Who'd you take the block to?

I have a guy off or Harbor Blvd at Vic's Harbor Machine, not too far from you.
The shop is a mess but his work is always great. If someone new just judged him by the appearance of the shop, they'd go somewhere else.
I've had several engines machined there by him. The only time I went somewhere else was Dels's in Sacramento and that is the only engine of mine that ever failed. It broke a rod between the big and little ends...

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446 C.JPG
 
I have a guy off or Harbor Blvd at Vic's Harbor Machine, not too far from you.
The shop is a mess but his work is always great. If someone new just judged him by the appearance of the shop, they'd go somewhere else.
I've had several engines machined there by him. The only time I went somewhere else was Dels's in Sacramento and that is the only engine of mine that ever failed. It broke a rod between the big and little ends...

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Thank you. I drove by Vic's today actually. You're right though, it's definitely not the most inviting place there is. I've talked to the guy a few times and he seems pretty knowledgeable. I've got some work I'll be needing in the near future and may see about having him do the work. Thanks again.
 
Yeah, that's the weak spot in SB head gaskets,... and where they fail when there's excess pressure/detonation/pre-ignition....
What do the piston crowns look like? That's a systemic problem there, big time.....lean condition, high temps, timing way off, crap octane.....combo..
 
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I'll get pictures of the pistons tomorrow. I do know that from what I saw, none of them showed any signs of detonation.
I must state though that I have never personally witnessed any signs of detonation firsthand. Typically, detonation supposedly leaves pick-like marks in the pistons, sometimes the ring lands break off. I only know this by way of pictures that I have seen online. These looked fine. They have the usual carbon spots but that is all. I thought that detonation also resulted in great wear in the upper shell of the rod bearings. These all looked new.
My 440/495 in my Charger had a detonation issue many years ago but the pistons looked normal when I had the heads off and those rod bearings were like new as well.
The LA and Magnum series all had just 4 bolts around each bore so maybe that explains the deformation? I'm not sure if the guy that owned this engine ran premium fuel all the time.
 
Very common for detonation to push the gaskets out the intake side. Happens a lot.
That is interesting.
If I recall, this engine had the pistons right near zero deck, (Maybe .010 below deck) the pistons have 5ccs worth of valve reliefs. With a 63cc chamber, what is the compression ratio?

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Even if I have it wrong and am .020 below deck...

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Over 10.25 to one with iron heads on no better than 91 octane?
 
Depending on the actual seat to seat timing on that cam, that's dancin' with the Devil, even tho' the fast-burn the chamber & squish gives You an advantage...engine temp, A/F, timing curve, and dealin' with 91pump is a chore.
 
I had no idea that the compression ratio was that high.
Knowing that now, I'd be tempted to buy dished pistons for this rebuild. I'm not looking to squeeze the last HP out of this, I want to make decent power but not so much that I'd be obligated to run 91 octane and limit timing to 30 degrees. I have dealt with engines with too much compression for pump gas and it sucks.
The Mopar Performance crate engines ran below 9.5 to 1 and they were rated at 300 for the one with the stock cam and 380 with the bigger cam. My cam will be somewhere in between so if I can get in the low to mid 9s of compression, I'd be much better off. 320-340 HP is more than I have with the '78 360 in the car now.
 
It looks like this piston has an 18 cc dish:

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That results in right around where I need to be:

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What are you thinking for a camshaft for this build?

The cam that came out of it has a number on the end of it. A buddy looked it up. It is a Hughes.....

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The cam specs of the MP crate 360/380 were something like:


MP 360/390HP magnum crate engine cam specs:
288°/292° Advertised Duration
(230°/234° Duration @ .050")
0.501"/0.513" Lift

9.0:1 compression.

The above was pulled from another thread here at FABO. The MP crate engine used a cam similar to their old school practice of long duration with moderate lift. Remember the big block 284-484, the 292-509? They sure had a lot of duration for the limited lift.
This Hughes cam is the opposite. I rode in the car that had these heads, cam and intake. It ran strong but I think it only had 3.23 gears. This beater Dart of mine has a 4.10.
 
The cam that came out of it has a number on the end of it. A buddy looked it up. It is a Hughes.....

View attachment 1716354378

The cam specs of the MP crate 360/380 were something like:


MP 360/390HP magnum crate engine cam specs:
288°/292° Advertised Duration
(230°/234° Duration @ .050")
0.501"/0.513" Lift

9.0:1 compression.

The above was pulled from another thread here at FABO. The MP crate engine used a cam similar to their old school practice of long duration with moderate lift. Remember the big block 284-484, the 292-509? They sure had a lot of duration for the limited lift.
This Hughes cam is the opposite. I rode in the car that had these heads, cam and intake. It ran strong but I think it only had 3.23 gears. This beater Dart of mine has a 4.10.
Are you sticking with that Hughes cam? Did it have the stock roller lifters with that cam?
 
I am going to reuse the cam and the lifters. The roller lifters seem to be stock, the they had the spider holddown and link bar. The lifters and the cam look perfectly fine.
At this point, I feel much more confident in building an engine that has a roller cam and lifters. I'm looking to convert the big block engines in other cars to roller setups too.
 
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