OK!

so im at this party, and this guy who claims to "know it all about motors" says his 78 Camaro has a 390.

I say, "what the hell is a 390?"

He responds by saying "A 390 is a 350 with a 327 crank and 307 rods, its an old racers trick"
Me not wanting to start an argument agree...and say "wow, I never knew that" while thinking this guy is full of sh$t!
He also says his car has GM production "Flotech" heads...I say..you mean Vortec...he says..no, Flotech....I say, wow, maybe ill get a set of those...

He also claims his car has a "Muncie Rock Crusher X"
While I know that there is a Muncie Rock Crusher, what the hell is a "X"
He claims that only about 1000 of those were built.

so, please tell me, do I know less about motors than I though, or is this guy full of it?

 

???
Ya got me. But if you get me really drunk I will still tell you I have a 708520 HD engine in my car.
I think my sig explains that one better.

 

I think he's drunk.

A 350 with a 327 crank is a 327 since they both share the same bore. All SBC con rods are the same length except for the shorter 400 rods so there's no difference between 350, 307, 327 or even 283 rods in length.

To my knowledge there's no 390 combination in SBC with factory production parts.

Flotech makes exhaust systems. Never heard the term used for production heads.

Maybe the X means it's a Super 10.

 

Next time ask him if you can have some of what ever he is smoking. Sounds like it's some good stuff.

 

this guy doesnt know what the hell he is talking about the only 390 was a ford engine,

 

The Olds 307 had 6" rods, not the 5.7" rods that the Chevy 350 has. These in the 350 will not give you 390 C.I.D., but it will raise compression considerably. Since the C.I.D is a measurement of bore and stroke, the only way to get to 390 would be a stroker crank and bored block.
In other words...

~M~

One other thing, if he has a '78 350 block he couldn't be running an original 327 crank, they were small journal, however they do make "new" 327 cranks with the large journal. And the Flow Tech heads are custom manufactured when ordered. They do not make a "production" head.

 

A 390 is a boat anchor Ford motor. But wait a minute...all Ford motors are boat anchors....silly me. Except for the old 427 "side oilers".

 

thanx for clearing that all up for me!!!

 

other drugs??the guy obviously had some numbers confused but since we're on this subject,what would a low mileage 1970 307 block,307 conn. rods and a steel 327 crank make????

 

That would yield a 327, not 390 cubes. 307s used 5.7" rods, too, IIRC.

Borg Warner made T-10 and Super T-10 transmissions, but Muncie X?

How long had this guy been at the party?

 

lol!
thats the thing, he told me this before we broke out the beers!

He also said that the only camaro ever built with a full frame was in 1967, and all others had unibodys, I thought that they didnt make the unibody until the 3rdgen, maybe I am wrong?

 

There were large journal 327 blocks and cranks. My dad has the original one in his 68 Nova, had it open many times and it's a large journal crank.....

3rd gen was the unibody. 2nd gen and 1st gen were sub-frame cars. 67-69 shared the same platform as the X-body (Nova).

 

Hwcoll95 , just to answer your question... a chevy 307 block, 307 rods, and a 327 crank would make a 307. 327 and 307 share the same stroke.

 

Nope first and second gen were unibody construction. Look for subframe connectors for the F bodies, only unibodies need subs.

~M~

 

First and second are "unibody" however they are different from third gens in that the front subframe can be unbolted and removed. The body is part of the chassis in that there is no factory framework joining the front and rear subframes.

All three versions need sub frame connectors to stiffen up the body.

 

Yea, you do.

The 390 is a special engine that was only available one year, 1978. They only sold 2 of them that year, one to a guy who worked for GM who I cannot remember his first name, but his last was Claus. The other was sold to some joker named Mr. Meoff. The cubes were actually rated low, the real cubes were more like 690. GM underrating stuff again, or a typo. The HP was awesome, around 1700HP and 2200TQ IIRC. The car was also super light, filled with then super high tech titanium and carbon fiber parts. They weighed about 5 pounds total. Very few people know about those 2 cars and the engines, but they do exist. Even more amazing was the price, the engine alone was available for just $100 over the normal cost of the car. The car itself with all the fancy high-tech parts was a mere $300 more than a normal Camaro, but most people couldn't afford that... you know $400 was quite a bit of cash way back in 1978.

Last I heard Mr. Meoff ran his at the track in Anaheim, CA called Fantasyland, and it ran a blistering 3.2@400 1/4. You should ask him if its for sale.

 

Wow. How do you know so much Madmax?

 

Wow.. I wonder how many more idiots are gonna take madmax's post seriously. (like the one above)

 

390 = 4.04 bore X 3.8 stroke

 

Haha yeah talk about idiots.

 

What? max is joking? I was just going to look up Mr. Mehoff to
see if the car was for sale. That would be a cool car to have.



Damn, 3.2 seconds is like real quick too.

 

Yup. I'd like to get my hands on one of them puppies. The Cobra guys would probably trade a hummer for one of those, and I'm not talking the truck...

IIRC, AMC (Rambler) also had a 390 in a few of their cars, and it was a "marine engine", too.

 

I would print madmax's reply and take it to the stupid bastard to let him know just how special his ride is. He musta got it from the GM guy, those special option cars trade hands so many times before someone figures out what they have. Just like my 87 1LE IROC.

Kelly

 

Is this possible? I'm guessing there's no way a 350 could be bored 4 hundredths of an inch over.

 

The bore would be the same as a .040 over 350. almost every brand of piston for SBC is available in a .040 over size.

 

This is a 391 if anybody gives a hoot. FWIW


1989 IROC Z
Owner: Dave Hutchinson
Engine: 391 CID (Marine Block) Top Speed(achieved) 155 mph
Clutch: Centerforce 1/8 mile 8.54 @ 84.5
Transmission: T56 6 speed 1/4 mile 13.2 @ 108
Wheels: SS Camaro 17 X 9 Altitude 4400 ft.
Tires: G-Force TA 275/40/ZR17Y Dyno HP 372 HP
Dyno Trq 455 ft/lbs
(dyno results at wheels)



Current Mods
6.4 Liter Chevy small block
4.03 bore 3.835 stroke (391 CID)
4 bolt marine block zero decked
JE pistons, Crower 4340 rods, zero gap rings
Steel "Stroker" crank (internally balanced)
AFR heads
2.02 intake 1.6 exhaust valves
Crane roller cam, 1.6 roller rockers
11.0 : 1 compression

 

Well join the ranks!

 

Was I not blatent enough with my sarcasm?

 

nope not blatent enough for me.

what is a racecar motor by anychance?

 

I thought you were.

I would still like to get my hands on one of those though.
3.2 in the 1/4 is sure faster than my 14 flatish.

I found a Mr. Jack Meoff in Arizona, I wonder if that is the guy?

 

there were both small and large(normal) journal 327 blocks made in the sixties. i believe the change over year was 68.


i must admit, my jaw dropped when when i read the "whats a 390?". i even have trouble typing it because i keep thinking in my head "what's a big block?"

jess

 

Yes, in 68 all small blocks went to the large journal when the
350 was introduced in the Camaro. The 327 large journal was
only produced in 68 and 69.

 

Well technically there was a 67 350 that was large journal and installed in Camaros, but the rest of the SBC's made the changeover in 68.

 

I've read everybody jokes and I hate to tell you this but it does exist, though not a factory set-up. A recent car mag-hot rod or super chevy recently built this and my buddies dad is seriously considering building it for his coupe. What it consists of is a 350 block, 350 crank ground down to accept the SMALL journal 327 rod. By boring .030 over and changing the stroke with the 327 rods you achieve an extra 40cc, believe it or not. They (the magazine-I will find out for sure which one as I prepare for flaming) advertised it as a 391. The one they built had torque starting at and continuing throughout the power band at over 400ftlbs of torque. I don't know how long the crank would last being ground down that much and how high it could be revved, but that's impressive torque. Now that I think about it, his other boy has a go fast catalog with a 390 short block all ready for like $1200.
Just remember not to flame too hard cause baby, the proof is in the pudding and I'll bring a whole bowl back at your asses!!!

 

Well make sure to give me a call when your 400 HP "391" runs 4s in the 1/4 mile at 400 MPH. Oh wait.. that will never happen, so you probably dont need my phone #. LOL

 

I believe those are 350 bored bored to 4.04" with a GM 383 CID 3.8" crank, yielding 390 CID.

 

You're almost as funny as me, ya know that?

 

Didn't AMC have a 390 in the Javelin's way back when?

 

And when did AMC ever put SBCs in their cars ? lol

 

Yes, in 67 they did produce large journal 350's but they were
only released to qualify the engine for NASCAR. You will never,
and I would almost bet my right nut, never ever find a production
67 Camaro (other than a Yenco) that has a 350 in it. As best as I
can remember the 350 wasn't an "option" to the masses until 68.
Even in 68 it was limited to the Camaro, the Corvette didn't even
get it until 89.

 

And just HOW in gawd's green earth does changing the rods to a 327's change the stroke of the crank? Because you see, its the crankshaft that determines the stroke of the engine, not the rods. Rods will help determine deck heigth and compression, not stroke or displacement.
I'm ready and waiting.

~M~

 

That's probably why madmax said that guy is almost as funny as him. Didn't you know if you put 327 rods in a 305 you get a 400 sbc ? Can you say.. cheap ? ROFL !

 

Alright Morley, it doesn't change the stroke of the crank-using the smaller rods along with boring, changes the bore and stroke. Just like if you put on 6" rods on a 350 crank-it changes the stroke-different geometry.

 

uhhhhhhhhhhhhhhhhhhhhhhhhhhh

(with face resting in hand, eyes peering through spread fingers)

Think about it, the connecting rod connects the piston to the
crank. It don't matter how long the rod is, it still connects the
piston to the crank. A crank with a 3.48" stroke is going to move
the piston 3.48" no matter how long the rod is.

 

A 327 rod, large or small journal, is the same length as a 350 rod. That's not how you change the CID by using those rods.

Putting 6" rods on a 350 crank also doesn't change the stroke. The stroke is merely twice the crank's rod journal offset. The rod length doesn't figure into the matter at all, ever. What longer rods will do, however, is to change the piston motion throughout the cycle; longer rods cause the piston to dwell at TDC and BDC longer, and to have higher velocity at the halfway points. This results in a slight improvement in thermal efficiency, i.e. more of the heat energy released by combustion being turned into mechanical energy instead of going out the exhaust.

What you do, is you take a small journal 327 rod, and a large journal 350 crank; offset grind the crank to the small journal diameter, which allows you to move the journal center farther from the crank centerline by ½ the difference between the large and small journal diameters. That's where the extra stroke comes from. That's .050" added stroke, but the price you pay is using the inferior rod. It was a popular way to cheat way back when in a motor that didn't have to last more than 30 laps or so, but doesn't make a whole lot of sense for the street. The extra couple of CIs aren't worth having to use rods with 11/32" bolts instead of 3/8" bolts.

This seems like an awfully childish thing for a bunch of people who don't understand (let alone remember) ancient circle-track tricks to get themselves all worked up over and calling each other names.

 

Bravo, (hands clapping), well said.

 

EVERY 1967 SS 350 Camaro had large journal cranks. EVERY ONE. NO factory small journal 350s. EVER. The 350 was available ONLY in the Camaro in its first model year of 1967.

How much are nuts going for these days? j/k. I've seen many '67 350 powered SS Camaros.

The SS Camaro in 1967 was available with either the 350 or 396. According to one of my sources, 34,411 1967 SS Camaros were sold.

jms

 

its a ford engine

 

jms, it's a good thing I DIDN'T bet my right nut huh?
I didn't know they put that many into production. I thought they
only released a limited number in 67 then made them standard
option in 68.

The wife would have been pissed.

 

Yes, offset the crank AND you do this with a 400 crank (3.75") to get an effective 3.80" crank. But you must still bore it 4.04", as mentioned earlier to get a 390.

For us 1 piece rear seal guys, the new 3.8" crank from the HT 383 is far simpler - again, as mentioned earlier. Better yet, just get a 3.875" crank to make a long stroke 396 small block. Much cheaper than grinding/offsetting a crank...unless you own a machine shop and can do the work yourself.