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Author Topic:   355,377,383 or 406?
shadowsarge
Dirt Full Roller

Total posts: 60
posted October 04, 2004 12:25 PM  
O.K. Here are the basics:

car will be a stret stock with coil springs, automatic tranny with a minimum weight of #3200 running a 3/8 clay oval(usually tacky)

Rules: stock unaltered cast iron intake (no bow-tie)(must have firing order)
dished or flat top pistons
No alum.,bow-tie or angle plug heads
No porting/polishing of heads/intake
Hydraulic cam
Stock rocker arms (no rollers)
Stock diameter valve springs (no dual)
Stock carb or Holley 4412 2 bbl.
Headers are allowed

Now the question - which engine would you use for the best performance with all these restrictions? Hope someone out there can steer me in the right direction.

Also, what are your thoughts, positive or negative, on the short blocks sold by PTM, Midwest Motorsports and JR Motorsports.

[This message has been edited by shadowsarge (edited October 04, 2004).]

redneck racing
Dirt Forum Champ
Total posts: 860
posted October 04, 2004 04:15 PM  
The track out here has gone crate motors and I think you are going to be seeing more of them. My engine is a 355 with keith Black 10:1 pistons moly rings and Eagle Rods I also use the 4412 with a set of headers the car turned 7200 rpm. If I have to I can put a restrictor plate on it to slow it down. Eddie

I-B-RACIN
Dirt Maniac

Total posts: 132
posted October 05, 2004 07:23 PM  
the 350 is the cheapest power and reliability you could ask for I agree with post above Kb flats with good heads z 28 valve springs work good for stock dia. the best flowwing cast intake is cast 4 barrel 055 last three digit Have to look up the rest of the #s if you needum..get a smaller lift cam with big duration (saves on the rick of spring bind)

racer17j
Dirt Forum Champ
Total posts: 5390
posted October 05, 2004 08:49 PM  
17j is right. with the limits of your rules, a 406 is the way to go. the intake system and hydraulic cam limits rpms, so you're going to have to rely on low end grunt. a 406 will "out grunt" a 355 every time.

the only scenario where a 355 might be better is on a dry slick track with a leadfoot driver... an experienced driver will do better with the 406.

[This message has been edited by outlawstock17 (edited October 05, 2004).]

allzway
Dirt Maniac

Total posts: 136
posted October 06, 2004 09:05 AM  
What about reliability issues of a 383 vs. a 406?

Or relibility of a 383 5.7 rod vs. 6.0 rod?

racer17j
Dirt Forum Champ
Total posts: 5390
posted October 06, 2004 04:54 PM  
It really depends on tires. Allways remember you gotta plant the power to the ground or you aint goin nowhere. narrow street tires and a gorilla motor dont mix. What tires are you running?

racer17j
Dirt Forum Champ
Total posts: 5390
posted October 06, 2004 08:55 PM  
406 vs 383

From what I've read, a 406 puts less stress on the rods than a 383 and makes more low end torque. However, a 383 will "tach" up quicker.

I had a Jr Motorsports 406 with Iron Eagle heads that was just scary fast. Unfortunatley, a bonehead (me) blew it up by putting a bad carb on it. The builder at Jr was very helpful.

[This message has been edited by WesternAuto17 (edited October 07, 2004).]

waltonjr1
Dirt Forum Champ
Total posts: 516
posted October 07, 2004 11:32 AM  
I ordered a 406 from Jr and they sent me a 408, anyway we bolted some worked vortec heads with a brezinski cast iron two bbl intake and put it in my friends Limited latemodel to finish the year and it suprised the **** out of us, he was winning his heat until the last lap took third and finished 5th in the feature. This is with there popular cs1087 hyd camshaft. I cant wait to put this motor in my streetstock. So far I have nothing bad to say about jr exept the fact they sent me a .40 motor instead of .30


racer17j
Dirt Forum Champ
Total posts: 5390
posted October 07, 2004 04:53 PM  
It may work in one motor but not the other, depends on the combo and heads, I know it pulls real hard in my motor. Im a comp man myself, I was going to pull it out and stick in a comp but figured I would give it a try. It will definitly stay.


nw15
Dirt Full Roller

Total posts: 28
posted October 08, 2004 04:29 PM  
Just so you know if your engine is being restricted a 355 would work alot better than a 406 in that the cylinder fill would be more complete with the smaller cui therby keeping your dynamic compression up. More cubes isn't always better, especially with a restricted engine...that is why there is a MIN and MAX CUI limit in the cup engines.

waltonjr1
Dirt Forum Champ
Total posts: 516
posted October 08, 2004 04:57 PM  
I dont know, there are some 406's around here that are hard to beat. I do agree that a 355 will run just as well but you wont make me believe that bigger cubes is a disadvantage, as long as the combo is right. I think most guys go wrong in the camshaft area with restricted motors, theres no need to go over around 530 lift on a 2bbl motor. It may sound good at idle but that dont mean its gonna run like it should.

[This message has been edited by waltonjr1 (edited October 08, 2004).]

nw15x
Dirt Maniac

Total posts: 129
posted October 08, 2004 06:30 PM  
I agree the cam is key

htrdr
Dirt Roller

Total posts: 13
posted October 08, 2004 06:41 PM  
i agree the right camshaft will make or break the combo no matter what cid .i also agree that there's no replacement for displacement . just chose the combo wisely .if you are in doubt contact the manufacturer ( comp cams etc)

iowa_dirt_track_girl
Dirt Freak

Total posts: 461
posted October 08, 2004 06:45 PM  
One of the things that i have found to be true is with a restricted head a bigger bore is definatly the way to go!Now here is the reason why,as the flow off the valve comes out is has more rome persay to come off the valve thu8s making it mix better and get a more even flow on top of the cylinder head that is why theorectialy a flat top piston will produce more horespower then a domed piston cause of the even flow over the top of the cylinder.
If you run somewhere the you can keep your rpms up pretty much all the time then a destroked 400 with a 307 crank is a pretty good way to go although it is very expensive to build that is what NASCAR runs is big bore short stroke.
Every one tends to forget that a 377 makes very very good torgue at the top end but not a lugger like the 383. So basically what Iam saying is if I was to build you a motor for your rules I would go with a 406 or 421 go with as big as bore as you can that way you heads will act so much better

    

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