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 :nono: 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 :thumbs: 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 :bigears |
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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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. |
Originally Posted by Gordonm
(Post 1576135590)
The block is not bored to 383 it is a 350 block bored .030 over with a stroker crank.
Originally Posted by Gordonm
(Post 1576135590)
No most good strokers are internally balanced.
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i know about the stroking part. it's a 377 if standard bore is it not?
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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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Originally Posted by bucky-katt
(Post 1576135732)
i know about the stroking part. it's a 377 if standard bore is it not?
377 stock bore 383 .030 385 .040 388 .060 |
Originally Posted by Gordonm
(Post 1576135804)
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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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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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" :( |
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. |
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. |
Nice looking build Husker, you can't beat the Callies parts for about the same price as forged Scat stuff.
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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 :cheers: |
Originally Posted by Husker
(Post 1576136350)
I have some other spec's if you want them.
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Originally Posted by MotorHead
(Post 1576136571)
Why dished pistons ?
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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. |
Originally Posted by Gordonm
(Post 1576136703)
What size cc are the cylinder heads.
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Originally Posted by The Collector
(Post 1576136700)
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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Originally Posted by MotorHead
(Post 1576136959)
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 ?
http://www.carcraft.com/techarticles...ion_ratio.html Take a look at the caption under the pic. |
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