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  #46 (permalink)  
Old 12-17-2012, 08:49 PM
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whats the advantage of a 6 in rod

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  #47 (permalink)  
Old 12-17-2012, 09:09 PM
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I understand you don't know this,but to ask a question on rod length opens up a long standing debate that has gone on for yrs.
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Old 12-17-2012, 09:16 PM
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Are you building a 350 or a 383? A 200cc head is kind of large for 350 street motor. The AFR 195 is a good head for a 383 and cost approx $1,400. You said you have a budget of $3K. Spend your money where it counts the most. You could stroke the motor and get a complete balanced rotating assembly for under $1K. However, machine work, carb and intake will eat up the rest of the budget quickly. If cost is a concern, the vortec heads are the "best bang for the buck". Scoggin Dickey Chevrolet in Texas can sell you a set already done with screw in studs and springs good for a cam with .575 lift. Read the articel that AFR didon their SBC 195 Eliminator head vs the 170 vortec head. First it is not a fair comparison as the 195 is substantially larger and should obviously flow better, and it does. But if you look at the chart they provide, the 170 vortec stuck with the 195 until 4K rpm. That means a lot. On the street the little 170 head will kick *** and have lots of power. You are not at 6Krpm on the street. Ask any knowledgeable head porter - you want the most air flow through the smallest intake runner. If 2 heads flow the same air and one is smaller - go for the smaller head. it will give more torque and won't feel sluggish down low. Don't make the mistake of going with huge head 200cc big cam on a 350. It will only make power high in the rpm range and won't be fun to drive on the street. Fort the low cost $, the vortec heads are a good deal and you can have a very streetable motor, reasonable mileage, and great power. Good luck
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Old 12-17-2012, 09:23 PM
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You can use either a 6 in rod or a 5.7. However, a 6 in rod is better in a 383, 5.7 is fine in a 350. Less friction in the bores with the 383. Slightly more dwell time at TDC for more cylinder filling etc. For a budget build, just use what you have or buy a complete balanced rotating assembly from eagle or scat. If you try to piece together mismatched parts it may be more trouble than it is worth and balancing may cost more $.
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  #50 (permalink)  
Old 12-17-2012, 09:23 PM
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The 195 AFRs can be used on engine getting close to 600 HP. Afr heads are great heads.If you insist on using AFR heads,at least build a 530 hp 383/ 0r bigger
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  #51 (permalink)  
Old 12-17-2012, 09:35 PM
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A 6" rod will have a bit less side loading on the cylinder wall. On a street/strip type engine I doubt there's a measurable power change either way. The piston can be made a little lighter w/a 6" rod, but the rod will be a little heavier. Even so I think the advantage, weight-wise, goes to the 6" set up. The 6" will be easier to balance internally. If external balancing there's basically no diff either way.

I'll put it like this: I'd use a 6" rod only if it didn't cost a nickle more to use than a 5.7" rod, all parts included. But that's me.

But then you're talking to a guy who shifted a stock 400 rod (5.565") in a 400 SBC at 6800 rpm too many times to count. Without a failure, nothing but ARP bolts. That taught ME that the whole long rod/short rod debate is a lot of hoopla over basically nothing.

I'm sure there'll be others who will disagree w/this and that's fine, too.
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  #52 (permalink)  
Old 12-17-2012, 10:31 PM
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A "open book build" is one without a budget and no time limits.You collect the best parts you can find when you have the funds to do so and without a time limit at the end you total what it cost.

That Eagle stuff is pure junk.Ya get what ya pay for.

Buy a decent stroker crank.\

All "kits" have to have the pricing they do by including leak links.Well the cheaper ones do.

Same holds true for the low dollar crate deals.

Build in a stroker for your expectations yrs in advance. Trust me you needs will grow.

Howards builds a really big bang for your money in a stroker.Good quality.

Make you plan and stick to it.No regret builds!!!. Big picture builds that understands it is all about combinations.A cam doesn't make a engine as a example.

Change you approach to this and you will not regret it.
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  #53 (permalink)  
Old 12-18-2012, 03:18 AM
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This is from the Isky tech tips. This is what Ron Iskenderian has to say about rod lengths:

Quote:
Tech Tip - 2005
Rod Lengths/Ratios: Much ado about almost nothing.

Why do people change connecting rod lengths or alter their rod length to stroke ratios? I know why, they think they are changing them. They expect to gain (usually based upon the hype of some magazine article or the sales pitch of someone in the parts business) Torque or Horsepower here or there in rather significant "chunks". Well, they will experience some gains and losses here or there in torque and or H.P., but unfortunately these "chunks" everyone talks about are more like "chips".

To hear the hype about running a longer Rod and making more Torque @ low to mid RPM or mid to high RPM (yes, it is, believe it or not actually pitched both ways) you'd think that there must be a tremendous potential for gain, otherwise, why would anyone even bother? Good question. Let's begin with the basics. The manufacture's (Chevy, Ford, Chrysler etc.) employ automotive engineers and designers to do their best (especially today) in creating engine packages that are both powerful and efficient. They of course, must also consider longevity, for what good would come form designing an engine with say 5% more power at a price of one half the life factor? Obviously none. You usually don't get something for nothing - everything usually has its price. For example: I can design a cam with tremendous high RPM/H.P. potential, but it would be silly of me (not to mention the height of arrogance) to criticize the engineer who designed the stock camshaft. For this engine when I know how poorly this cam would perform at the lower operating RPM range in which this engineer was concerned with as his design objective!

Yet, I read of and hear about people who do this all the time with Rod lengths. They actually speak of the automotive engine designer responsible for running "such a short Rod" as a "stupid SOB." Well, folks I am here to tell you that those who spew such garbage should be ashamed of themselves - and not just because the original designer had different design criteria and objectives. I may shock some of you, but in your wildest dreams you are never going to achieve the level of power increase by changing your connecting rod lengths that you would, say in increasing compression ratio, cam duration or cylinder head flow capacity. To illustrate my point, take a look at the chart below. I have illustrated the crank angles and relative piston positions of today's most popular racing engine, the 3.48" stroke small block 350 V8 Chevy in standard 5.7", 6.00", 6.125" and 6.250" long rod lengths in 5 degree increments. Notice the infinitesimal (look it up in the dictionary) change in piston position for a given crank angle with the 4 different length rods. Not much here folks, but "oh, there must be a big difference in piston velocity, right?" Wrong! Again it's a marginal difference (check the source yourself - its performance calculator).

To hear all this hype about rod lengths I'm sure you were prepared for a nice 30, 40, or 50 HP increase, weren't you? Well its more like a 5-7 HP increase at best, and guess what? It comes at a price. The longer the rod, the closer your wrist pin boss will be to your ring lands. In extreme situations, 6.125" & 6.250" lengths for example, both ring and piston life are affected. The rings get a double whammy affect. First, with the pin boss crowding the rings, the normally designed space between the lands must be reduced to accommodate the higher wrist pin boss. Second, the rings wobble more and lose the seal of their fine edge as the piston rocks. A longer Rod influences the piston to dwell a bit longer at TDC than a shorter rod would and conversely, to dwell somewhat less at BDC. This is another area where people often get the information backwards.

In fact, this may surprise you, but I know of a gentleman who runs a 5.5" Rod in a 350 Small Block Chevy who makes more horsepower (we're talking top end here) than he would with a longer rod. Why? Because with a longer dwell time at BDC the short rod will actually allow you a slightly later intake closing point (about 1 or 2 degrees) in terms of crank angle, with the same piston rise in the cylinder. So in terms of the engines sensitivity to "reversion" with the shorter rod lengths you can run about 2-4 degrees more duration (1-2 degrees on both the opening & closing sides) without suffering this adverse affect! So much for the belief that longer rod's always enhance top end power!

Now to the subject of rod to stroke ratios. People are always looking for the "magic number" here - as if like Pythagoras they could possibly discover a mathematical relationship which would secure them a place in history. Rod to stroke ratios are for the most part the naturally occurring result of other engine design criteria. In other-words, much like with ignition timing (spark advance) they are what they are. In regards to the later, the actual number is not as important as finding the right point for a given engine. Why worry for example that a Chrysler "hemi" needs less spark advance that a Chevrolet "wedge" combustion chamber? The number in and of itself is not important and it is much the same with rod to stroke ratios. Unless you want to completely redesign the engine (including your block deck height etc.) leave your rod lengths alone. Let's not forget after all, most of us are not racing at the Indy 500 but rather are hot rodding stock blocks.

Only professional engine builders who have exhausted every other possible avenue of performance should ever consider a rod length change and even they should exercise care so as not to get caught up in the hype.
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  #54 (permalink)  
Old 12-18-2012, 04:37 AM
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I do not have a budget right now. Its kinda aopen book like gary said. My first choice was the bowtie small port vortec. The have a 66cc cumbustion chamber and a thick deck. They have 185cc intaker runners and 65cc exhaust. They have 2.0 inch and 1.550 exhaust valves, but need upgraded springs. They are a really good head for the price at just around $1200 for the pair.

Last edited by ChevroletSS; 12-18-2012 at 05:03 AM.
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Old 12-18-2012, 04:53 AM
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1Gary how do I need to change my approach. First thing Im getting is a rotating assembly. Second, my cylinder heads. I think you are assuming that Im just focused on a cam. That will be the last thing I buy. Ill buy a cam that goes with my cylinder heads.
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  #56 (permalink)  
Old 12-18-2012, 06:13 AM
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Quote:
Originally Posted by BigEd36 View Post
This is from the Isky tech tips. This is what Ron Iskenderian has to say about rod lengths:
The old man Ed used to just shake is head about that kid Ronnie.LOL

That ref has been posted on another thread already.

Let's just say certainly there are equal number of people that supports the

use of 6" rods.

Lastly.We don't have to use anyone's name to prove a point.If you have a

opinion given your experience level and the experience level of most of the

members on this forum should be enough.
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Old 12-18-2012, 06:56 AM
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Quote:
Originally Posted by ChevroletSS View Post
1Gary how do I need to change my approach. First thing Im getting is a rotating assembly. Second, my cylinder heads. I think you are assuming that Im just focused on a cam. That will be the last thing I buy. Ill buy a cam that goes with my cylinder heads.
I used buying a cam as a example.3 grand doesn't get it done.Tailor a build around it's intended use,where does the engine spends it's rpm a majority of the time.Torque curves starting off idle or say at 2,000 are one hell of more useful on the street than building big hp numbers and end up with a high and shorter torque curve.Guys talk about big bangs for their bucks on combos that end up with hp peaks at 6500,but don't consider those parts really aren't such great buys considering on the street the limited number of times they actually get to use it.A bad return on a investment really.In the same hand buying parts that by the nature of the "cheap deal" they are,barely covers the use currently and not any expansion in the future.Gear it and use a T/C stall to have it run just at the beginning of the torque curve.Tailor build a torque curve considering the wt of the vehicle as well.

Lastly,understand any time your investing in a build for a gen 1 SBC,your investing in not current tech is like in the LSx engines.As fast as that tech moves,you could find yourself left behind quickly.......................
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  #58 (permalink)  
Old 12-18-2012, 06:59 AM
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you need to get on track as to what you are building? what is the engine going to have as a main task? are you driving this thing daily? Has your budget changed? You can have anything you want if you throw enough money at it.Go back to the beginning when you said 3k budget
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  #59 (permalink)  
Old 12-18-2012, 07:08 AM
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Yeah Vinnie.I am suggesting he changes his point of view about the limitation of 3K.

I would venture a guess you have yrs into your car/project.
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Old 12-18-2012, 07:10 AM
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I wasn calling you out I was just trying to talk specifically to you. When I first started this post back when I joined I said my budget is 3 grand. Thats not the case anymore as a I can afford more now. Just want to clear that up. I dont have a budget but Im not gonna spend 10 grand on a motor either. As far as what your saying about tourque curve I agrree 100%. That bein said why couldnt I use those AFR 195cc heads and make good low end torque. The other head option I was looking at is the bowtie small port vortec. Which do you think would be better on a 377 stroker?

Dont take what I said wrong. I just dont understand why I have to change my approach to this build when Im on here to get help. It just sounded like you were assuming I was building my engine around a cam. I dont doubt anyones experinece level on here or I wouldnt be on here. I greatly appreciate your advise or critism, good or bad. It will only help me out. So again thanks to all of you who help and like I said before bare with me as I have never built a PERFORMANCE engine only stock.
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