Suggestions please...600hp sbc buildup

[rustbucket79]

Cheers from a fellow Canuck located in BC!

Your stock block has a couple of weak points, one you can correct, the other you cannot and will have to live with the consequences (if) anything happens.

Toss the 3 center main caps for splayed steel. The stock caps are made of plain old grey cast iron, and don't deal with detonation well. I just finished a 4 bolt conversion on a 817 block, #3 and #4 cap were in 2 pieces, thank goodness the M55 pump broke off and alerted the driver of the lack of oil pressure. How long it would have lasted will never be known, but the main bearings with the broken caps were in excellent shape other than some polishing where the crack was. Splayed steel main caps will help to stabilize your expensive steel crank and keep it where it belongs. You can still expect to see a little front and rear main cap metal transfer if you see detonation or spin the engine high. A front steel cap can help as well as a strapped rear cap, but at some point (like where you're headed with your build) you're better off finding your local ERI member machine shop and have him cut you a killer deal on a World Motown block. (or Dart)

Even though you sonic tested .220" on the cylinder walls (common on the 400's to be this thick, at least the ones I've measured) but the problem area isn't there, it's every place where a head bolt is located. The walls are cast with a relief the length of the sleeve and that thickness is considerably thinner and is the weak point of the cylinder. Why GM didn't cast the cylinders full diameter and just use blind head bolt holes certainly must have been due to cost, and is standard on the bowtie blocks, as well as Dart and World. Oh to not have to fuss with leaky head studs....... Again, detonation is the killer here, and squeezing 600HP on pump gasoline is going ot take tuning to keep it alive. For safety's sake, I would dump a pail of race gasoline in the tank for track days, something to think about.

Good luck!

[lowflyr]

Rustbucket,
I hear ya on the splayed caps, and I only plan to use this block for a few(3?) years, again mostly street duty with 5-6 trips to the track in the summers. I do *hope* the stock block takes it, tuning is going to be critical and I know it. Race gas is very likely on track days.

Troy/Joe,
I will try a few different carbs out, likely 750, 850, 1050. It should prove interesting, the 750 will be undoubtedly weak compared to the others, so in effect the test is really between an 850 and a 1050. As long as the engine idles and doesn't stall all the time during its street use, then I don't mind going with the larger carbs. This engine is all about upper midrange and top end power, the chassis isn't ready for this level of power, but what the hell, it'll be fun.

ARN,
Agreed, the lifters and springs are critcal here. Time will tell how this plays out. I would sure be interested in comparing dyno sheets once we get these things together. Sounds like you'll be besting me on both power and torque fronts this time out.

Thanks everyone

[A Atwood]

ARN,
Agreed, the lifters and springs are critcal here. Time will tell how this plays out. I would sure be interested in comparing dyno sheets once we get these things together. Sounds like you'll be besting me on both power and torque fronts this time out.

Thanks everyone

I will be tuning this thing on a dyno when I finish it, so I will have a dyno sheet. Will be happy to share my results. It will be a few months though. ARN

[ItsA68]

Its amazing, but I'm also doing about the same thing. I'm even an ME. : ) Not sure if I'm ahead or behind you though...but I have most of what I need except for my fuel system. I decided not to compromise, and am shooting for the full on Kinsler EFI-IR setup. So far I have:

Little M - splayed steel mains
Callies 3.75 stroke pro magnum crank
Lunati 6" Pro-mod rods
JE Pistons with JE std rings, for 10.8:1
Brodix Track 1 fully ported heads 215cc T2 program
Stahl 1 3/4 step- 1 7/8 headers with stahl pattern and adaptor plates.
Crower Solid Roller 248°/254° @ .050" with .597"/.587" and 112 sep.
Schubeck Roller-X solid roller lifters
Crane "quick lift" shaft rockers (got a deal on e-bay : ) )
Champ RR pan, and 10552 Melling pump. 10%more volume.

Mine's going in a 68 Pro-touring Camaro with about the same goal as you with mosly street and some strip/road coarse work. I know I could make a lot more power on the top end with a much bigger cam, but I really wanted more than anything, something that would live on the street. My springs I know are a little on the light side with only 175/475 seat and open, but I really don't plan to spend much time at more than 6Krpm. I probably should have opted for a hydralic roller, and may end up changing it before I'm done....OR I might just put more spring on it, spin it higher, and change them often. The Roller-X are also a risk I know, but the few reports of people that are using them seem positive. The Isky's with bushings could be an option too, but I already have the Schubecks.

You might want to look at the Voodoo solid roller's that were designed by UDHarold when he was at Lunati. If I didn't already have the Crower, I'd probably get one of these. ( I found out about them about a week after the Crower arrived )

I think the biggest challenge of getting this kind of combo to work on the street is valve train reliability. This seems to be the key, with frequent lash checks, and inspection being the things to do. I'm hoping I have enough spring. From what I have read here I may be light....if I don't spin it as fast, should I be OK?

~~fred

[CNC BLOCKS]

Fred where are you located???

[ItsA68]

I'm in the Atlanta metro area. Have a good bead on a couple of engine shops that build stuff locally for the circle track folks at Dixie speedway, and Lanier. Should be able to get good service. Wonder if anyone local reads this board?

[longrodsbc]

Its amazing, but I'm also doing about the same thing. I'm even an ME. : ) Not sure if I'm ahead or behind you though...but I have most of what I need except for my fuel system. I decided not to compromise, and am shooting for the full on Kinsler EFI-IR setup. So far I have:

Little M - splayed steel mains
Callies 3.75 stroke pro magnum crank
Lunati 6" Pro-mod rods
JE Pistons with JE std rings, for 10.8:1
Brodix Track 1 fully ported heads 215cc T2 program
Stahl 1 3/4 step- 1 7/8 headers with stahl pattern and adaptor plates.
Crower Solid Roller 248°/254° @ .050" with .597"/.587" and 112 sep.
Schubeck Roller-X solid roller lifters
Crane "quick lift" shaft rockers (got a deal on e-bay : ) )
Champ RR pan, and 10552 Melling pump. 10%more volume.

Mine's going in a 68 Pro-touring Camaro with about the same goal as you with mosly street and some strip/road coarse work. I know I could make a lot more power on the top end with a much bigger cam, but I really wanted more than anything, something that would live on the street. My springs I know are a little on the light side with only 175/475 seat and open, but I really don't plan to spend much time at more than 6Krpm. I probably should have opted for a hydralic roller, and may end up changing it before I'm done....OR I might just put more spring on it, spin it higher, and change them often. The Roller-X are also a risk I know, but the few reports of people that are using them seem positive. The Isky's with bushings could be an option too, but I already have the Schubecks.

You might want to look at the Voodoo solid roller's that were designed by UDHarold when he was at Lunati. If I didn't already have the Crower, I'd probably get one of these. ( I found out about them about a week after the Crower arrived )

I think the biggest challenge of getting this kind of combo to work on the street is valve train reliability. This seems to be the key, with frequent lash checks, and inspection being the things to do. I'm hoping I have enough spring. From what I have read here I may be light....if I don't spin it as fast, should I be OK?

~~fred

I would change the springs, I had a 72 chevelle, 355 solid roller, I used lighter springs and my cam was 244/244 .604/.604 110* the heads were Dart Iron eagle 215cc, it would not pull past 6000 it just simply nosed over, I tried everything, and I ended up with bent pushrods, I pretty much left it alone because I was pulling the wheels on launch but on top, well it didnt have any TOP end, I used the same cam in a 383 went from 1.6 rockers to 1.5 with larger diameter springs (and more pressure as well) I shifted@6500 regularly and on occasion Id twist it to 7000 same heads/intake/carb and cam and yes I was surprised at how the exact cam from the 350 was a totaly differnt animal with the 383, it didnt have the exhaust note the 350 had but it sure did perform waaay differnt. same car as well..

I have since only used no less than 210lbs seat pressure on a solid roller application, it just isnt worth the risk imho anyways...


longrodsbc

[bigjoe1]

I am surprized noone has mentioned a REV KIT. Old man ISKY himself told me that the rev kit woulg make the life of the roller lifters go up by a factor of 10. It is true. only certain lifters will work with the rev kit, but it does eliminate the stop and strart of the roller bearing, which must be what dills them in the first place. In the old days, everyone used one. Why not now ?? JOE SHERMAN RACING

[lowflyr]

ARN,
It'll be a few months before I get mine together as well. It certainly will be an intereting comparison. I can't wait til I fire it up.

Fred,
I'm with longrodsbc on the springs, you should definitely keep things under control in the valvetrain. Solid rollers are hard enough to keep alive on the street, no sense letting a known potential problem by you at this stage in the game. Your combo is indeed very similar, these things should be alot of fun when we get them going.....maybe I should be going for an aftermarket block before I get too much further with this......why is my wallet starting to feel nervous again??

Joe,
Funny you should mention the rev kits. I had always thought it was a good idea, but I have been told by so many people that they don't work that I never tried one out. The whole idea makes sense, and specifically the loss of contact between the roller and the cam certainly could not help at all. You said the life could be as much as 10 times improved??? Holy, if thats the case, I'll be trying out a rev kit on this build no question. If it even doubled the life it would be a huge gain. Have you heard anything negative about the rev kits?

-Brad.

[Troy Patterson]

It would be worth clarifying what is meant by "driveability."

I have experienced and observed high performance engines that were weak, I mean not wanting to get the car rolling from a dead stop even with step gears in the rear.

Driveability above tip-in / off-idle can surge, buck, not want to take the throttle, etc.

Beyond that, the engine is weak, still resisting throttle ((but to a lesser degree,) if you get too aggressive the engine may cough, backfire, whatever.

Then you come on the cam and everything straightens out.

All of this is indicative of exhaust gases contaminating the fresh a/f mixture, poor atomization, poor metering signal strength, poor metering, bad combustion.

An awesome carburetor can alleviate almost all of this, and bring the cam in a thousand rpm or more earlier, produce more horsepower and torque, and radically improve driveability, be it on the return road, in a road course negotiating traffic, or even on the street. Emissions are reduced by improved combustion - "emissions" are not just for smog regulation, but pertain to engine development as in efficiency, the quality or improved ability of the carburetor to meter fuel under various conditions (and therefore make more power and respond better), as well as cam / cyl. head / header / engine combinations (for the purpose of making more power and responding better), to win races and increase enjoyment.

Troy Patterson TMPCarbs.net TMP Carbs

[lowflyr]

Troy,

I do not care if the car feels weak pulling away while under light throttle. I do not want backfiring and stalling though. To me, being weak off the line is a benefit for hooking on street tires anyway. I know the street tires won't hook once the engine 'comes on cam' unless at part throttle. Slight misfiring is also preferably avoidable, but again poor burning may cause some of his. I am not building the car for fuel economy, no concerns there. I do not want the car to be carboning up everytime I take a drive. If I can avoid having to clean the sparkplugs every tank of fuel because of poor burning at the lower rpms, I would prefer it. But I CAN live with that, I know a carb is not going to give the same amount of taming of a hot cam that a fuel injection system can.

I believe what I am looking for is easily achievable with a decent carb and tuning. I really do not want to buy a higher stall converter (3000 now) because the auto will be going as soon as I can get together the money for a jerico 5 speed, although a TKO 600 has its own appeal at a much lower price...... in the end the car will be somewhere around 2700rpm at a cruise in top gear on the highway, so I figure that should be enough rpm to keep the bucking as a result of misfire away.

-Brad.

[Troy Patterson]

Brad,

My last posting wasn't about nor directed at you specifically. You are not the only person who has or will read this thread, it is a thread on the internet with world wide access, so don't think it's all about you.

I began writing my last posting in an effort to clarify terminology. It was late, and time to put the kids to bed, so maybe I finished it off in a hurry.

I'll respond to your "thoughts."

Perhaps, you've never been at a racetrack and stalled the car in the pits because of that weak low end you describe, or on that particular day due to atmospheric conditons your poor running engine / carb / tune was too far off the mark and you couldn't get it re-started.

Perhaps, you've not yet lost an engine due to poor combustion resulting from weakness in low end (not resulting from design or purpose) but because you had an inferior carburetor and / or tune in it, not able to meter fuel well.

Perhaps, you've not yet diagnosed properly an engine blown or experienced unnecessarily short engine life due to prolonged poor combustion and resultant heating, detonation problems and excessively high pressure spikes wiping out ristpins, main bearings, cranks, rods, pistons, etc.

Perhaps, you're not a carburetor engineer / expert / tuner researcher and don't understand the inner workings of the carburetors metering system and how it relates to overall engine function, operation, performance and life.

Perhaps, I'm giving you too much credit still.

Without this knowledge and experience with, on or around performance engines (or exposure to it) it is not likely you will understand the contextual value of the information I relayed. And without common sense, it is unlikely you will know it is of value when you hear (read) it. And again, I know this from personal experience since I've been guilty of naivete myself coupled with a certain ignorant arrogance, or is that arrogant ignorance?

I'm not speaking about what I hope, think or believe, I speak from / about what I know as fact, from 28 years of experience. I was a bit of a prodigy at 15 yrs old when I built my first 3x2 set-up myself - from non-original carbs and did mild tuning on them.

The things I post are for those who are open to new information and increasing their knowledge and undestanding, maybe it's not for you, maybe you are not ready.

I don't care if you don't care. Thanks for sharing, I guess.

Troy Patterson TMPCarbs.net TMP Carbs

[lowflyr]

Troy,

I am having a hard time determining what your last post was all about. It sounds like its intended to belittle me.......I don't know what brought this on. I can only assume there was a communication error somehow.

I started this thread to find out what advice I could get for this build. This thread is about my 600hp pump gas build, the combination I will use to do it, and what suggestions people may have. So yes, this is about me. You posted asking about/talking about clarification of "driveability". I responded with what I was looking for. Your last post is a personal attack.

For the record, I stated "I don't care if the engine is weak pulling away......" I appreciated what you had stated about driveability, and I clarified what I was looking for. I was looking for a response from you either agreeing that I can meet my goal or to tell me what I'll need to do to meet it if I'm not there yet. I in no way meant anything derrogatory towards you. I did not say anything about not caring what you think.

Also for the record,
1) I have been racing for a few years now, but I have building engines for 10 years.
2) I have lost engines to poor tune/detonation etc.
3) I have experienced short engine life as a result of 2), but I HAVE diagnosed the problems and have never lost a second motor to the same problem.
4) I understand carburetors, and what the engine wants well. I am a capable tuner and have spent alot of time tuning on a dyno and at the track. I am very familiar with modes of failure as well as the root causes.
5) Credit is earned.
6) I fully understand what you were talking about in the driveability post.
7) It is not possible to know how much common sense a person has or doesn't have from a few postings on a website.
8 ) I am always open to new things, but I am looking for specific comments with respect to this build. Although your information was not new to me, it did appear to be asking for clarification.
9) I am always on a quest to learn as much as I can. Every article, every experience, every opinion is valued.

Here is the kicker....I don't particularly bother me that you don't care that I don't care. But the fact of the matter is that I do care about peoples' opinions or I would not have asked for them. Again, I do not care that the engine is weak down low. I do care to hear opinions and suggestions.

I have no doubt that you are knowledgable, and you are trying to help myself and others. I would never hold that against anyone.

Perhaps before you slam someone, you can decide to send them a pm rather than try to attack them in public. No one deserves to be chastised in public over a simple miscommunication. I treat everyone with the utmost respect and I expect it in return.

If you have something to add to this post that can help me achieve my goal, please do. I still do value your opinion and I will not hold a misunderstanding between us against you. It was you who posted about using a 1000-1100cfm carb......I will be testing this combo with a 1050cfm solely based on your suggestion. Does that sound like someone who does not care about your input??

-----------------------------------------------------------------------------------

To everyone else.....
My apologies, its posts like the these last couple that can destroy the enjoyment in reading these threads.

I do still have a couple of questions left unanswered throughout this thread, and I would really appreciate if there are some suggestions here:

Joe has mentioned rev kits (as did I in my Feb 15th 4:32pm post) and he appears to support them....other than cost, is there any other drawback? I can imagine that it would be a good idea to lower valve spring pressures if a rev kit is used because of the added pressure on the solid roller lifter. Anyone have tips regarding this?

Also I noticed that no one has mentioned anything about bearing clearances(I asked about this in my original post). I know this is affected by the oil used and the rpm range as well as typical operating temperatures and load. Up until now I have used 0.0030 as my target for rods and mains when using 5w30 mobil one synthetic for my engines (all street/strip between 300hp and 450hp). My acceptable range has been +- 0.0005 for both as well. Any suggestions?

[Wolfplace]

You don't want to lower spring pressure with a rev kit.
The purpose of a rev kit is to keep the lifter in contact with the lobe not as a bandaid for less spring.
I think rev-kits are an excellent addition to any endurance engine but don't see a real reason for them in a drag race deal except for the safety factor.
I would prefer to use them in BB's too if they were not such a pain with the goofy pushrod angles.

As for bearing clearances, in a small block I like .0022-.0028 as a nominal clearance & prefer the lesser in most cases.
Depends on what the engine is for, RPM & what you are using for oil as well as your attention to things like warming the engine up.

[Ed-vancedEngines]

Brad,
This street drivability subject comes up in a lot of the threads and we each must have a different concept and idea of what is called drivability.

Troy pretty much nailed it on the head in his post reply. This explanation needs to be framed and carried back into every thread we have talking about street drivability.

I have two different methods of looking at street drivability;
One is drivability for customers.
The other is drivability for me.

I have learned that those two are far a different from each other.

I guess becuase you are talking about driving this is why he made this reply in your thread. I hope he copies it and keeps posting it into other threads as well.

The ones of us who are experienced at posting on Tech Forums have tendencies to address the original poster but to also add in other tidbits that others who will read may need or want to know. That is why at times threads look to get sidetracked and then go back into the topic and away from it and back into it. We are posting for the original poster and for all others who may have a need to know.

Ed