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Author Topic:   377-383-406 Which is best for who?
posted February 04, 2004 10:48 AM
With equal lower end parts, which of these 3 motors is my best choice?

The car is a 3000lb street stock with a 6.20 gear, the track is a big 1/4 mile with one sweeping turn and one fairly tight, the heads are World Sportsman or Dart Iron Eagle, the carb is a 750 dbl pumper and compression will be 11:1. With my old (blown up) 406, I'd hit 6500rpm on a good lap.

I'm looking for opinions here. I really liked the 406, but would like to know some opinions on the high point and low points of these 3 motors.


posted February 04, 2004 10:55 AM
At that rpm and on a smaller track with a heavy car the 406 and 383 would be better because of the extra torque. The 377 would work well on higher rpm and lighter cars. Not to mean it woudlnt work but just need to turn more rpms.. just my opinion anyway.

posted February 04, 2004 11:14 AM
The 377 is an RPM motor that works when torque is evil.
The 383 makes more torque than a 350 and near what a 406 would make, but wouldn't like to rev as high. The bore is too small to get good flow to rev super high.
A 406 will make good torque and can rev higher than a 383 because the bore is .125" larger than a 383. The bigger bore lets the valves breathe better.

In my opinion, all else being equal, 377 = high RPM HP, 383 = low-end & midrange torque, 406 = compromise of the two with a bit more overall because of the extra CID but not excelling in either low or high rpm.

Ego Racing
posted February 04, 2004 11:29 AM
All Things equal there is no exchange for cubic inches. IF THE TRACK CAN HANDLE IT!!! I had a 421 ci and got SMOKED by a 305 on a very slick track! For your car and a tacky track I would build the 400 if you have the block but change the rods and pistons. You need at least 5.7 or 6 inch length rods.
I drove for a car owner who had been in racing so long I think Jesus drove for him. We were funning a 406 in Florida in a LLM. Tracks down here have a sand base so about 1/2 the way through the season the track would be good to start and go VERY sick!!!
The track was so slippery some cars were spinning going into the turn and if you stopped at the bottom the car would not climb the bank.
For the feature the track was dusty! He pulled the #6 plug wire and pluged the intake runner with a rag. I could almost flat foot the car out of the corner due to the lack of power. I passed 17 cars in 10 laps to finish 3rd. They stopped the race becaues it took over 30 minutes just to finish the 10 laps we ran there were so many wrecks.

posted February 04, 2004 01:51 PM
With that much carb, it's cubic inches! 406, or bigger all the way.

posted February 04, 2004 05:36 PM
Ok, I'm curious. I'm buiding a 5.7 406 flattop. My track always goes dryslick. I built the 406 cause I couldn't talk myself out of it.LOL During the extreme slick, if I pulled a plug wire (which one?), would that cause damage to my motor? Just Curious. Thanks, Race

Ego Racing
posted February 04, 2004 07:09 PM
Yes it will cause damage! A LOT OF DAMAGE! The Feature was only 15 lips and I didn't think I was going to make it. The Sponser didn't care. He had more engines than a shark has teeth. He ran a Junk Yard, he got mad when people called it a "Salvege Yard" but he speialized in used performance stuff.

posted February 05, 2004 07:24 AM
As far as too much torque is concerned, I'll quote a good freind and fellow driver -- "That's why the accelerater is a pedal and not a switch."

I'm no engine expert, but pulling a plug wire doesn't seem like it would ever be a good idea.

So far, it sounds like the 377 doesn't quite have the torque to pull me off the corner. Between a 383 and 406, which engine puts more stress on the rods and other bottom end parts?

posted February 05, 2004 08:04 AM
Whats a 331? Some unatural mating of a 305 and 350?

posted February 05, 2004 08:52 AM
The 331 he is talking about is prob the .030 over 327. 4.030 bore, 3.25 stroke. Basically the same idea as the 377, bigger bore shorter stroke but on a smaller scale. There is also a 400 crank in a 305 block that makes something like a 334, but i wouldnt even consider that option.

Between the 383 and 406 i would prob go 406 simply because its not going to cost much more to build if any and it will breathe better due to the bigger bore size. Plus it keeps the bigger main journals so there is a little more strength in the crank throws. On the other hand 350blocks are easier to come by and 383 kits are pretty common and reasonable now. If you are not planning on turning more than 6500 or so then its prob a toss up.

Remember as far as having to much torque goes you can play with cam timing and also cam duration to move the torque curve around. Going with a longer duration cam will move the peak torque up (or down) in rpm so that you dont get that burst of power at the wrong time. You can tune it to the tracks you run and make it easier to hook up.

posted February 05, 2004 09:50 AM
Originally posted by WesternAuto17:
Between a 383 and 406, which engine puts more stress on the rods and other bottom end parts?

The stress on the rods and other bottom end parts is determined by the rod/stroke ratio.
The engine builders say to build a rod/stroke ratio of around 1.8-1.9 which is impossible to get that out of a 3.75" stroke crank. The closest you can get is 1.73 ratio with a 6.500" rod in a 9.500" deck block. This will give you a pin height of 1.125"

The most common nextel cup car motors are 4.155" bore 3.300" stroke and that makes a ratio of 1.87

[This message has been edited by 2nd2none (edited February 05, 2004).]

Ego Racing
posted February 05, 2004 03:30 PM
The 334 is not that bad but it is a motor that dose not like a ton of rpm or a lot of rpm flux. It likes to run in a very narrow rpm range. The max rpm we ran them was 7000. And we always had them overballanced about 2-3%.

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