377 vs 383

[John Scott]

Had a long talk with the local racers the other afternoon. After discussing the 383 and the 377 (400 w/ 350 crank), I was wondering why this isn't a more popular engine for the wheel spin happy Zs. The 383 is a superior torque motor, and gobs of hp, but w/ the light weight of the Z, wouldn't the 377 be a good choice? Its said to be very reliable. Every indy, exotic, competition engines, i.e. RACE, hot cycles etc have the over square design of the 377. Bigger bore/stroke. As I understand it the 377 allows more high end hp and the bigger bore is better for flame propagation, piston speeds. etc. At 6000 ft this combo. with some good heads and cam produce a high 10/ low 11 in a 3300 lb street driven car. Anyone consider this engine, or is it too obscure?

 

[This message has been edited by John Scott (edited May 05, 2000).]

[Guest Anonymous]

Just a quick question John...how do you get the 350 crank to work in the larger 400 journals? Are there bearings that are thicker to allow for the undersized crank to work? I considered this swap before I decided on the 383 but dropped it mainly because around my area 400 blocks are either junk or are too expensive. I'm also not too keen on having the primary power range at a much higher RPM. I will be just adding lower gears in the diff to compensate for the rediculus amount of torque the 383 will produce.

 

SpencZ

MonsterZ Cont.

[John Scott]

From what I understood there are bearing spacers. Basically a bearing double stack! I would agree this sounds like odd design, but one friend of mine is in his 4th year of hard racing with no failures. In his case its a really fast reving engine with plenty enough torque to pull it through the 1/4 w/ a 2 speed.

JS

[John Scott]

The guy I talked to liked the big bore short stroke design of the 377. He wanted to do something a little different for his camaro. His performance #s are pretty amazing for the weight of the vehicle. 11.1 @ 118. Aprox low 420s hp at Bandemiers 6000' altitude. Closer to 500 @ sea level. He's running a lot faster than some of his bigger cube camaro buddies. Maybe he just hit a good combination. I know he has Brodix heads, but they're untouched, as is. He knows he can bump the hp #s up but likes where it is as a street/strip car. I'm not knocking the other motors, I just thought it was an interesting set up.

JS

 

[This message has been edited by John Scott (edited May 06, 2000).]

[Guest Anonymous]

The industry trend is definitely towards larger bore and shorter stroke. Especially if you have good, large cylinder heads, add short rods to the recipe. (Short rods will add to instantaneous piston speeds, and reduce rod/stroke ratio, but when power is the name of the game a race engine will use a shorter rod.)

 

Anyhow, the 4.125" bore is more and more advantageous the more radical you go. NASCAR engines aren't 4" bore and 3.48" stroke, they use the largest bore and smallest stroke possible. Also, John, add less valve shrouding to the list of advantages.

 

500 flywheel hp from any small block is pretty easy to do nowadays, and wouldn't require the large bore to do. The 377 combo you describe, however, would make at least as much power as a 383, and be more durable from having less stroke.

 

There is an issue with cooling and 400 blocks, but I've heard from respected sources that it's a non-issue when dealt with properly.

 

Lastly, the bearing spacers seem to work great. Fords use them to put Cleveland crank journal sizes into a 351W block. In that application failures are unheard of.

 

 

 

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Michael Sen-Roy

Houston Performance

281-893-6080

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[Ray]

Have you guys seen a large bore 350?? It is a 400 block with a 307/327 crank in it. You use Ford 300-6 conecting rods(modified) and a modified long rod 400 piston. Big bore long rods and realitively cheep. They really spin up fast!!! If you do one use the special thick bearings not the spacers. I beleive federal mogal makes them. The spacers don't transfer heat away from the bearing as well. Anybody know of any other neet combo's?????

 

[This message has been edited by Ray (edited May 06, 2000).]

[Guest RON JONES]

I would think that the 377 might scare some people because of the bearing spacers(that is how they do it).Another thing is if your going with the 400 block,why not build a 406cube motor.Takeing away cubes isn,t the most popular thing to do,and I think most people are looking for more cubes.Thats why the 383 is a very popular motor,more cubes out of a 350.Personaly I would think the 377 would be a good motor for a lite car with alot of camshaft and alot of gear.In a car that weights in at 3300lbs, the 406 would bring better performance.

 

[This message has been edited by RON JONES (edited May 06, 2000).]

[pparaska]

I remember reading about this engine. The nice thing about it was the rod/stroke ratio was better than the long (6.0") rod 350, and therefore can handle more compression due to the slower. piston speeds near top dead center. The magazine that covered the build up and test reported on in incredibly high and flat torque curve, and if I remember correctly, it didn't drop off until the late 5000's or early 6000's rpm. Something to think about!

 

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Pete Paraska - 73 540Z - Marathon Z Project - pparaska@tidalwave.net">pparaska@tidalwave.net -

[Guest iamjackal]

Hey John Scott what else do you know about that 377 because that is what Im building now.Ive got my block but Im still planning the motor.See I found a kit for 500 that is the full rotating assembly but I will be running nitrous also so I may go all forged which is not going to be cheap.I can find no research or info on these motors.Not even a horse and torque curve. I dont want the torque of the 383 in a 2400lb car So Im going with this.Sucks though cause i wanted to run AFR aluminum heads, but I fear cracking the block since the block has no water jackets between the cylinders.

[John Scott]

Iamjackal, I really don't know squat about the engine. It just seemed a great alternative for the light weight Z. I do know the few running the combination around here swear by it. I could ask one of the local racers if it would be allright to give his number to you. He's been running the 377 for 4 or 5 years with excellent results. No break downs, really consistant. He uses the Brodix heads. Let me know if you want to make contact with him.

JS

 

[This message has been edited by John Scott (edited May 26, 2000).]

[Guest tom sixbey]

Hey - ray?

 

where did you get the info on that short stroke, big-bore 350? - i was wondering if such a motor existed.. - i'd like to read up on that if anybody can tell me where to look for the info.... Do the 400 blocks weigh any more than a 350 block?

 

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Tom 6B (73NIC)

 

"why slam on the brakes when you can slam on the gas?"

[grumpyvette]

the 383 uses the far more comon 350 block, as its basis with coolant between the cylinder walls, the 377 uses the far less comon 400 block, they make aproximately equal hp but the 383 makes it at about 400 rpm lowerin the rpm band, the 377 has less valve shouding, and a better bore to stroke ratio, and I used to build lots of them BUT THAT WAS BEFORE WE FOUND that building a 406sbc useing the 383s 3.75" stroke with a 4.155 bore in a 400 block you get even more hp and torque so if youve got a 400 block thats the route we usually suggest

[cockerstar]

Uhhhh, Grumpy?

This thread hasn't been posted in for more than 8 years...

[Pete84]

What advantage is their to destroking a 400 down to a 377? Quicker revving?

[jt1]

377's were the preferrred motor for dirt tracks for quite a while. They would make as much top end hp as the 400's, but had a good bit less low end torque. This made it easier to hook up the car off, while still giving a big run down the straight. They worked especially well in mid summer when the track went dry slick earlier.

 

The spacers were a pita. Usually you had to install them, them line hone the block to get them to last. I had one blow so hard one night that the only thing I saved was the waterpump. A piece of the cam cracked the intake, and in the big wreck that followed the blown engine, the car sitting crossways on the hood of my car ruined the carb and distributor.

 

That was my last 377.

 

John

[grumpyvette]

Uhhhh, Grumpy?

This thread hasn't been posted in for more than 8 years...

 

is there a time limit on posting good info?

[jpdavis]

In a word, no.

[DavyZ]

is there a time limit on posting good info?

 

 

Post away, my friend!

 

Davy