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Old 12-06-2010, 04:51 PM   #1
The Collector
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Default 350 to 383 Stroker

I have searched far and wide on this forum and found that most 383 stroker project questions cannot be fully answered because not enough info is given to begin with. Well, I recently found that the running 1980 that I bought does NOT have a stroker as the seller indicated. I wasn't expecting it to be, as the Vette was running and in excellent condition for 4K. Now, I want to stroke the motor. Not drop a BB, not stroke it to a 377, not stroke it any further than 383 cu in. Here's what I know:

1) I have a $7000 budget, $3500, $4000 MAX on the motor
2) The block is to be bored to a 383
3) The crank used will be externally balanced and cast
4) I am going for the 500hp/500ft-lb mark; perfectly doable
5) Redline at no more than 6000rpm, max hp @ 5500rpm preferred
6) Street/strip, more a summer weekend driver
7) Hi-Rise dual quad intake, hood will be cut
8) AFR 195cc Competition Heads. I am firm on this aspect.
9) Comp Cams hydraulic roller, with 236/242 of duration @ 0.050 in. lift, and 0.520/0.540 in. lift, maybe a tad more aggressive if req'd
10) MSD 6 Ignition
11) Dished pistons will be used
12) 5.7" I-beam connecting rods, I don't care for the extra 5hp associated with the 6.0" rods, it isn't worth the hassle. No H-beams
13) NEW rods will be purchased built for strokers; I will not grind my current rods.
14) MSD 6al Ignition (of course)
15) Comp ratio should fall in the 9.4 to 9.5 area
16) 1 3/4" headers
17) Vette has a 4 speed Muncie
18) Flywheel was stock; this is how I know the motor is too.
19) For the love of God no nitrous
20) Once again, externally balanced. Most strokers do it that way and I will too.
21) I will worry about the chassis later, VB&P has nice deals

Now, my setup is very vague and would love your input, as I know you cannot beat the experience and knowledge found within this amazing community. However, I want everything to stay within my boundaries, as this is after all my car. Now for the good stuff; the specifics

1) Is this (p/n 935050) crank fine?
2) I have narrowed my heads to (p/n 1094) & (p/n 1095), which one?
3) Press fit or floating rods? See my camshaft.
4) What's the difference between press fit and floating rods?
5) Piston p/n's to consider? Dished only, domed is out of the question
6) Suggestions for all the other good stuff? This includes springs, valves, timing chain & cover, hints & tips, rockers, lubrication (not sure what I heard on that), etc, etc

These are just my first steps, I understand there's more to it but this is a good start, I look forward to your responses. As always, I thank you all in advance. I think I've blabbered on enough
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Old 12-06-2010, 04:54 PM   #2
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my biggest concern in doing a 383 with my spare motor is the extra side loading that is sometimes associated with stroker motors. i have NO experience at all when it comes to gm stroker motors, just the problems associated with doing a 347 from a 302 ford. excessive side loading on the cylinder walls can cause premature wear. i understand that with the ford motors at least, that has been remedied by doing offset piston pin position.
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Old 12-06-2010, 05:19 PM   #3
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No most good strokers are internally balanced.
The block is not bored to 383 it is a 350 block bored .030 over with a stroker crank. A 3.75 stroke vs the 350s 3.48 stroke.
500 HP is a lofty goal for a cast crank, you can do it but why not build a durable short block. The 5.7 to 6 inch rod you will get plenty of arguements each way. I personally have 5.7 rods and have no problems buzzing it to 7000 rpm. The cam is a good one and the heads should get you in the high 400s for HP and TQ. You are going to lose performance by using the dual quads vs a good single 4 barrel and good intake. Yea it looks cool but are you after looks or HP. You can run 10:1 no probelm with aluminum heads. I'm jus tshy of 11:1 and run it on good pump gas with no problems.
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Old 12-06-2010, 05:29 PM   #4
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Quote:
Originally Posted by Gordonm View Post
The block is not bored to 383 it is a 350 block bored .030 over with a stroker crank.
Sorry, got caught up with emphasizing the need to make it a 383, meant to say bored .030

Quote:
Originally Posted by Gordonm View Post
No most good strokers are internally balanced.
The only issue with this is that it's much more work and money, and to be quite honest, that's beyond my level of experience. The 500hp/ft-lb mark is a goal, not that I would ever expect to ACTUALLY reach it with dual quads. I would run a 750 Double Pumper if I did. I am willing to scarifice power for looks, as dumb as it may sound.
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Old 12-06-2010, 05:30 PM   #5
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i know about the stroking part. it's a 377 if standard bore is it not?
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Old 12-06-2010, 05:37 PM   #6
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There is actually no more work going internal than external. If you go external your balancer and flywheel are no good from your 350 which is internally balanced. You have to buy a crank and rods and pistons. They are going to cost the same regardless if it is external or internal. No difference in any machine work or clearancing for the block either. I see no reason to go external.
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Old 12-06-2010, 05:38 PM   #7
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Quote:
Originally Posted by bucky-katt View Post
i know about the stroking part. it's a 377 if standard bore is it not?
Yes

377 stock bore
383 .030
385 .040
388 .060
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Old 12-06-2010, 05:45 PM   #8
The Collector
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Quote:
Originally Posted by Gordonm View Post
There is actually no more work going internal than external. If you go external your balancer and flywheel are no good from your 350 which is internally balanced. You have to buy a crank and rods and pistons. They are going to cost the same regardless if it is external or internal. No difference in any machine work or clearancing for the block either. I see no reason to go external.
Hmm, I never thought of it that way. What crank would you recommend for an internally balanced 383?
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Old 12-06-2010, 06:12 PM   #9
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Your best bet is to buy a rotating kit. It comes with the crank rods and pistons. This way they will be matched. You have to decide do you want a forged or cast crank, which rods and what type of pistons. Forged hyperutectic or cast pistons. Your budget will dictate some of this also. There are good ones and there are bad ones out there. Do your homework and decide what you want. Mine is forged crank and pistons with rods good for 700 HP. I'll probably never get there but there is room to grow and I'd rather go overkill than under. I never worry about the short block.
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Old 12-06-2010, 06:13 PM   #10
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Well now I did a bit more research and found this bit of info on the very popular "Ultimate Guide to the Chevy 383 Stroker" which I found on this forum and is very reputable:

"While externally balanced engines have survived for decades, heavy external weights are more likely to put a twist in the crank at higher engine speeds. To minimize this, many 383 cranks are also offered internally balanced. This requires Mallory, or heavy metal, to be added to the crank throws to offset the amount of weight normally added to the balancer and flywheel/flexplate. This is a more expensive process, but internal balance does offer durability advantages. Several crank manufacturers offer an internal balance option for 383 stroker packages either as separate cranks or complete rotator packages"

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Old 12-06-2010, 06:31 PM   #11
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Either externally or internally you will be having a machine shop balance it for you. If you are after 500hp you need to be looking at 10:1-11:1 compression, not the 9s.

As for cranks you can use a Scat forged crank or better yet and probably still within your budget is a Callies Compstar forged crank. Check out Callies, CNC motorsports, flatlander racing for rotating assemblies.
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Old 12-06-2010, 06:35 PM   #12
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Hey Collector,

Good to see that you've done some homework. This site rocks and offers a lot in the way of information.

I might be one of the newer 383's out there in the forum. I had a very reputatble builder construct my 500HP engine. We used some of the best parts. Including a Callie crank which may have been excessive, but my builder would not budge. It's internally balanced which again for high perf engines, is the way to go.

Any who, I ended up spending about 7k for then rough engine and assembly. Plus another couple of thousand with other pieces and parts to bring it all together.

Check out the link on my google pictures and you can see some of the pieces and parts.

http://picasaweb.google.com/jimbodow...vette383Parts#

http://picasaweb.google.com/jimbodow...etteNewEngine#

I have some other spec's if you want them.
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Old 12-06-2010, 06:44 PM   #13
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Nice looking build Husker, you can't beat the Callies parts for about the same price as forged Scat stuff.
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Old 12-06-2010, 06:58 PM   #14
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The parts start to add up, especially when they are forged and you want to get into the 500HP territory you're gonna bust your budget just on parts.

There allot of them. I see all the time people looking at say a forged rotator assembly for say 3 grand, nice crank, rods and piston. But by the time it's in your car you have spent 3 X at much, like I said the small stuff adds up and they ain't cheap either.

Why dished pistons ? In my opinion a flat top is the best in just about any street / strip motor. Sometimes you can't find a flat top you like or the flat tops that are available don't come in the specific compression range you want. That's what happened with my 427ci so I had to go to a dished piston, but like I said flat top is better
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Old 12-06-2010, 07:05 PM   #15
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Quote:
Originally Posted by Husker View Post
I have some other spec's if you want them.
That would be awesome. Although I know I won't hit the 500 mark or match your setup, I think it's in my best interest to gather as much info on other 383 setups as possible. I am looking into these rotating assemblies and the prices don't look too horrific. What type of dished pistons would you recommend for AFR 195cc Competition Heads? There appear to be many styles, but I can't quite find the "inverse dome" style ones :/
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Old 12-06-2010, 07:12 PM   #16
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Quote:
Originally Posted by MotorHead View Post
Why dished pistons ?
Well, it's because I remember reading that the best dished piston design (the inverse dome) retains the quench portion of the piston to create better cylinder mixing as the piston approaches top dead center, which usually results in an engine that is less detonation sensitive.
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Old 12-06-2010, 07:12 PM   #17
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You have to figure your compression ratio out. What size cc are the cylinder heads. There are calculators somewhere that can figure your compression ratio. All yo udo is plug in the numbers. This way you can see which pistons yo ushould be able to use. You should be able to run a flat top piston. I run a flat top with 68cc heads and am 10.8 to 1 compression. I can't remember exactly but I think my pistons are -6cc pistons due to the valve reliefs. My pistons are only .002 in the hole which raises my compression slightly also.

With that cam and those heads with the right setup of intake and carb you will be real close to 500 HP and maybe touch it depending on the dyno. Of course dynos don't run on the street. That combo with good compression of around 10 :1 should be a great street motor.
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Old 12-06-2010, 07:34 PM   #18
The Collector
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Quote:
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What size cc are the cylinder heads.
That was actually one of my questions. For now, however, my head of choice would be the 195cc intake 65cc combustion chamber.
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Old 12-06-2010, 07:35 PM   #19
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Quote:
Originally Posted by The Collector View Post
Well, it's because I remember reading that the best dished piston design (the inverse dome) retains the quench portion of the piston to create better cylinder mixing as the piston approaches top dead center, which usually results in an engine that is less detonation sensitive.
Is that comparing it to a flat top ? Or is it just general information on a dished piston explaining what happens with the best dished piston ?
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Old 12-06-2010, 07:40 PM   #20
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Is that comparing it to a flat top ? Or is it just general information on a dished piston explaining what happens with the best dished piston ?
Yes it is, I found that at:

http://www.carcraft.com/techarticles...ion_ratio.html

Take a look at the caption under the pic.
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Old 12-06-2010, 07:40 PM
 
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