80 Rocket

To the OP, slade69.....I saw you were hoping to pull up to 5000RPMs. My question would be why are you shooting so low, especially with a small block? A small block wants to rev. If you decide to go with an aluminum head with a bigger cross sectional area compared to a stock small block head, you will have to spin it higher to take advantage of the head.

I would try to tailor your combination for a max RPM of somewhere around 6000-6500. You are going with aftermarket rods and good CP pistons. I would consider internally balancing the engine as well, and don't cheap out on the valvetrain. I would buy Pro Comps bare and set them up for your application.

Big blocks have the advantage of lots of cubes so they can make more torque down low. Small blocks want to rev and could use some assistance along the way with gears and converter.

I think you got the right idea, but don't sell yourself short on RPMs. Your combination can handle it. I was going 6500RPMs on a completely stock short block for 5 years of drag racing.....still can't kill it.

slade69

[QUOTE=cutlassefi;890256]All the bearing shells have extra clearance built into them for the rear main. Leave it alone, it's designed that way because it's so wide. But if you must, Sealed power makes a .001 under bearing shell for the small blocks I believe.
Don't use that rod, use the one with the 7/16 bolt and with that you don't need the ARP2000. That's a waste for your build.

Good point. I must have missed 7/16 option, but good catch! Differece in cost is not much, probably worth it. I updated my order accordingly.

cutlassefi

Yes, Tom Allen is the owner. Bill is his main head porter, he's been there 30 years. Whenever I'm there, which is pretty often, I always try to pick Bill's brain. We talk percentages, radius' as well as valve angles and bowl depths. Great guy and very good at what he does. Note; he did my Procomps. They're filled and only have a 2.125 intake yet flow 312-315@.600. I'd say he knows what he's doing.

Slade69- yes sub out that rod for the one with 7/16" bolts. You could also do the Mahle piston which has an even better ring pack than the CP. Just a thought.

slade69

Yea you right. That 5000rpm plan was before I realized my original #5 heads are useless.

slade69

CutlassEfi ; I'll go with CP Bullet pistons now, but in general interest, tell me more about MAHLE pistons, any prod.no:s available?
I have used Mahle pistons in European engine builds and always succeed, they are of good quality, no doubt.

slade69

About that #5 main extra crearance. I can't help thinking it will bend the crank under load, thats why I want to get rid of it. Overall, my clearances(radial ones) will be on the loose side, probably around .0038".
Other than that, I don't understand why extra radial clearance is deeded due to wider #5 cap?

cutlassefi

If you're really at .0038 then you can either do the .001 under Sealed power bearings or have it ground. But don't change the rear clearance alone.
You seem to be suggesting that the bearing is supposed to support the crank, that's completely wrong. The film of oil is the support, the crank should never touch the bearing, ever. The rear journal will have more load on it being in the rear with the converter etc. It needs more clearance/oil film, which is built into the bearing shell.

Mahle piston # 930200225 will go with a Scat rod # 2ICR6125-2000-7/16. Hope this helps.

slade69

Yes I am aware of oil film, of course. Maybe the factory calculated that wider rear main with more oil film area is capable to maintain thicker oil film in #5 compared to others, but this is just my theory.
About oil film carrying the loads, yes kind of agree but the oil film just transits the loads from crank to bearing shells and to main webs of the block.

slade69

My build takes a step ahead. I got the delivery from Summit. New piston(CP bullet)+pin+rings+locks with new rod(Scat60)+bearing are quite much lighter than original. New set weights 1330,7g vs old 1632,3g. There will be quite a lot of material removed from counterweights when balancing I think.


About balancing, should harmonic balancer and timing gear and flexplate be assembled or not when balancing? Anyhow they should be untouched and all material removed from crank, right? Is this what you call external balancing?


If balanced without harmonic balancer, timing gear and flexplate, this will be internal balancing? Correct me please if I am wrong.

HWYSTR455

Usually, you would want to do an 'internal' balance job. Any peripherals would then require to be 'neutrally' balanced. If a peripheral needs to be replaced, you can then just simply purchase a 'neutral' version.

So you in this case yes would take your balancer and flexplate in to the machine shop when you drop it off to be balanced. Not the timing gear, those are already neutral.

This is where you should make sure you have a quality SFi balancer and flexplate.

.

slade69

Ok, CP bullet series pistons came with sheet telling the piston gauge point diameter is 4.122". What should my bore size be honed to? Thinkin about 4.126 to 4.127. Would that be right?

olds 307 and 403

Aren't they are 4.125" piston advertised? Cutlassefi schooled me on the advertised dimension has the clearance built in, makes sense when you think about it. But .003" sounds tight for a 2618 piston. Contact either CP or Bill Travato at BTR Performance, since he helped design them what the final spec should be.

slade69

Yes they are advertised 4.125. That's the theory like you told, but to me too it feels tight with 0.003". There is no downside to go a bit looser I think.

Ryan 1969 Chevelle SS396

Awesome build information!!

I am processing, and learning.

So many variables.

Ryan

slade69

My crank is at grinder, and should be ready soon. Next step will be balancing. I want to do an internally balanced engine and relized I can not use my original flex plate, because it is not neutral, it has a welded weight on it.
Any suggestions for a reasonable neutral one for example from Summit? To go with th350.

slade69

Another thing are piston rings that came with CP Bullets. I am not sure if the top ring is a nitrided one or a chrome ring. Any advice how to identify? The honing process should be slightly different.
Also the top and second rings have marked with letter "N", not T or dot as I have seen before. This "N" goes up, right?

cutlassefi

I assure you they're not chrome faced. They would most likely plasma moly. Have it honed for a plasma moly faced ring.
Yes N would normally go up. But on the top ring the inside bevel goes up, on the second ring the inside bevel goes down if it's a std reverse twist. If it's a Napier then the notch goes down as well.

slade69

You are propably right. Top one is barrel shape faced and has the inside bevel on same side as "N", facing up.
Second one is napier with oil hook facing down.

slade69

I got the crank back from grinder. Everything else went like planned, but sideways the journal widths vary some. I think I will compensate by grinding the sides from few rods and after that weight the big ends again and adjust the weights.

slade69

Now it is about the time I have to order a cam. Before, Cutlassefi recommended a custom 221/227 (.050). I am still thinking between flat tappet and hyd.roller. Cost of course would quide towards flat tappet, but I'm a bit concerned about the break in process, changing the valvesprings after brake in and oil additives, it's quite a hassle. How are your real world flat tappet experiences, did you have any problems, and do you really need looser valve springs for brake in? Are the roller benefits worth the money?


Engine is coming together as follows:
Sbo 374 stroker, 3,5 stroke(scat 60 rods,sbc small journal), 4,125 bore, Flat tops(Cp Bullet), made to zero deck
Compression ratio about 9.7 to 1
E-Brock heads(unmilled, out of the box, maybe valvesprings if I have to)
E-brock Rpm intake
750 carb
Headers+2,5 duals
Prepared to go with higher than stock converter, probably 2400 stall.




I'm considering following (hyd. roller)cams, opinions welcome


Lunati Voodoo hyd roller adv.272/280 .050 221/229 lsa112 Lift 0,549/0,565
Howards 514825-10 adv.278/282 .050 225/229 lsa 110 Lift 0,560/0,555 This is a 4/7 swap.
Comp XR 276 HR adv.276/282 .050 224/230 lsa 110 Lift 0,505/0,505


If going flat tappet, what cams would give similar performance?


Reasonable overall driveability, good street manners, healthy feeling power, power range to 5500-6000 are the goals, so please don't ask about goals and budget

Ryan 1969 Chevelle SS396

This engine will be "All that and a bag of chips"!!!!

I am very interested in this build, although mine will be milder, I am following closely, and would love to see video when running.

Will you dyno break in and tune?

Ryan

slade69

Do you also have a sbo stroker build? Milder was also my plan originally, but the head choice lead me to this plan. My iron heads were cracked, 2 sets of them.
No, I don't plan dyno. Will be tuned in the street with wide band lambda. But that's still far away. This is a slow build. Can't afford to buy everything needed as once. Cost of heads was not on my orig. plan.

Wonder if anyone hasn't any experiences/opinions about those cam related issues, pls see my previous post?

cutlassefi

Hmmm wide band and lambda are two totally different terms for two totally different things.
Cam choice will depend on budget and ultimate goals. Flat tappets are cheaper but rollers typically offer better performance apples to apples as well as not requiring high zinc oils etc.

Ryan 1969 Chevelle SS396

My build plan currently will have similar rotating assembly but not stroked. More mild/stock top end than your build.


Ryan

slade69

Air/fuel ratio gauge with wideband lambda sensor. As simple as that. To me, wideband lambda sensor is one type of lambda sensors among others?!?But my brain works analogy, not digital



What do you think about dual pattern vs. single pattern cams? What are the benefits from longer exhaust duration(vs. intake dur.)
There are also opinions out there that single pattern will always create better torq than dual with extended exhaust duration.

cutlassefi

Apples to apples a single pattern will typically enhance low end torque at the expense of higher end hp. That would be dictated by your desires and overall combination.
Hope this helps.

Thanks.

slade69

My crank was balanced today. It came soon obvious that internal balance is difficult to achieve. A LOT of mallory should be used. Of course that would be something "nice to have"-things, and just use neutral externals.
BoB-Weight was 1845g. So the balancer and flex plate with original weights had to be assembled and about 300g of steel was drilled from counterweights. Externals were left untouched.
To achieve real internally balanced sbo ,piston and rod combo should be very, very light and still probably some mallory needed. maybe possible with alu rods and 400g:ish pistons.

slade69

Ok, my 375 stroker build is finally coming together. The car is a runner now but not without troubles. Combination now is as follows:


- Crank stocked to 3,5"
- E-Brock heads
- 9,75:1 compression
- Howards 219/228 at 050 hyd. roller 4/7 swap
- Rpm intake
- 600 vac Holley (yes, smallish)
- Stock distributor with crane Xri pointless conversion
- Long tube headers, 2,5"duals
- Ignition timed 12° initial.


Starts well, temps gets and keeps steady 185F, oil pressure cold 60 psi with 10/40 oil.
I haven't managed it to run well, it kind of runs rough, it shakes at idle more than I wish. When driving, it hesitates a lot around 2500-3000. Above that, it is very smooth and seems to have nice power as well. Trying to readthe plugs, any ideas, seems odd to me. All others seems lean but no.5 rich?!? Overall, left bank seems richer, I can not understand this with 180° intake. Any ideas?

olds 307 and 403

I would check the wire on number 5 and maybe swap the plug. Otherwise, you need a tuning kit or step up to a 750 which would probably be closer, definitely lean. The Quickfuel Slayer 750 is a good Holley style carb for cheap. What is your timing curve like? Glad to hear it is running.

slade69

I will check the plug wires and dist. cap. Also have to check for vacuum leaks and the carb to intake connection. I know the 750 carb would be better size, but it should definetly be possible to get it run right with 600 also, just lefting some hp on the table.
I'm not really familiar with Holleys, and wondering how can I make the idle and transition circuit richer, there is no slow circuit jets?!? to change. My idle mixture screws are already 2 1/4 open.
Ign. curve is too wide I have lo limit it somehow. At idle I'm at 12° and total is more than 40°, must be too much. These are numbers with vacuum disconnected.

olds 307 and 403

I believe there is limiting bushings for the points distributor or you need to make a manual stop. For street performance, there is nothing wrong with 38-40 total, although the Edelbrocks heads should require less timing to run ideal, a much more modern chamber design. The Street Demon 750 is another carb to consider and should be close out of box. They are a new 3 barrel castings design heavily based off the Carter Thermoquad carb with their problem areas eliminated. You may need to intake center notch the divider to clear the back barrels. You will gain mileage and power over your 600 Holley, both with an ideal tune. If you must keep your Holley, I would go up 2 jet sizes on primary and secondary. I am no Holley expert at all. I know the better Holley style carbs have adjustable idle air bleeds to richen the idle mixture. Try turning your mixture screws out till you get the best idle.

cutlassefi

If you need to turn the idle screws out 2.5 turns then your idle circuit is too lean. But on that carb you'll need to extract the existing bleeds and install smaller ones. However I'd just get a 750 Quick Fuel Slayer or similar and go from there.

Jmo.

slade69

The carb is not responding to idle mixture adjustment like it should. One turn out from seat or 2,5 really doesn't make big difference. I pulled the carb and noticed my primary butterflies are so much open that they exposes the transition slots too much at idle. I think this is the reason why it doesn't respond to mixture screws. On the other hand, I can not adjust butterflies closer because it won't idle any more. Bigger than stock cam probably causes this situation needing so much air at idle.
Blaah...., what can I do? I know some tuners try to avoid this problem By drilling small hole to primary flaps. Then you could adjust them more closed position. But anyhow, this drilling does not make the slow circuit any richer. I'm beginning to admit, that this Holly 600 vac is not very tunable carb. No tunable low circuit, no changeable jets or bleeds. Secondary metering plate does not even have changeable secondary jets...... It's really a piece of s**t if you ask me today Seems I really need to locate a better carb.


Yes I know you gearheads have already told me few times to get better one and you were right all day long. Just need to make my own mistakes and learning by mistakes seems to work best for me My learning curve is bend from heavy gauge wire

olds 307 and 403

Either get the 750 Quickfuel Slayer, Mark suggested or the Street Demon 750 carb. You have a nice performance build, why limit it with too small of a carb. Guys on here have found the 625 Street Demon carb set up for 9 to 1+ and a mild cam. The 750 version is supposed to have a richer calibration. I would imagine mileage isn't that important with this build. The Street Demon 750 should have a economy advantage with both carbs properly tuned in. Either carb is a step up over that current 600.

slade69

You are right, the mileage is not the first priority in this build, still trying to keep it somehow reasonable. Today I bought Street Demon 750, so let's see how it ends up. One big reason for choice was it was available from stock locally, did not want to wait it for weeks. In my book, it is a pure street carb, not a race one by any means. It has the choke tower and secondary flap, both limiting air flow some, but it's ok for me, this is not a race build. Tunability still leaves something to hope more, no changeable air bleeds or slow circuit jets. Still, there are some points in design I like, fuel level is below the gasget surface to minimize possibility of leaks, double primary boosters to help atomizing of fuel. Air blow holes below the idle mixture drillings to help atomizing at idle. Also I like the goggle style secondary butterfly, it's huge! Secondary goggle butterfly is also kind of mechanical, and airflow/spring operated secondary flap is adjustable by screw and locknut. Simple, I like. This carb kind of changes its jets sizing according to engine vacuum, a cool feature, might help to save mileage. To my eye, Street Demon also looks cool, simple and clean.
Alredy took it out of the box. This carb is very light. Seems I have to tweak with throttle cable and re-route some vacuum/fuel lines. Air cleaner needs to be modificated also, I have to raise it a bit.


Couple of questions for you experienced engine builders; How do you recommend to set up the crankcase ventilation? Just simple generic breather cans to valvecovers and call it a day or something more sophisticated? With or without PCV-valve?
And for CutlassEfi: How do you air-gap Olds sb RPM intake?

cutlassefi

Sounds like you just jumped out of the pan and into the fire. You couldn't find anything better in a few days or so? Too bad.

olds 307 and 403

The Street Demon is a good carb, very few bad reviews, unlike Edelbrock carbs. I bet it will run night and day better. His cam isn't huge, it should idle decent. They have a full tuning kit available. They fixed almost all the Thermoquads defects with this new 3 barrel. Let us know how it runs out of box. I am surprised the Quickfuel Slayer wasn't available on shelf somewhere over there. Run a PCV valve and a breather wigh a hose to the air cleaner is neater.

slade69

I'm aware of the weaknesses and was willing to take a risk. Let's see how the story goes.....

slade69

Last night I got the Street Demon assembled mostly, and did the first start. It fired up, electric choke was a bit short, needs adjustment. When reached normal operating temp, it was idling better than with Holley without touching anything. Not even the curb idle screw. Without load it was reving ok without any hesitations. Vacuum is 12hg when with Holley it was 15, but the idle is lower with SD. I'll let you know when I get to drive it. Have to mod the air cleaner to fit first.

olds 307 and 403

That is the one thing they didn't improve on was the Thermoquad's annoying venting, almost forgot about that. As others have found, the Street Demon fire up and run good out of box, good start. It is a square and spreadbore design, make sure it sealing properly against the carb flange and the back 3rd barrel clears the intake divider. The choke should be an easy adjust, just set it slightly tighter. I was going to buy that carb but I had a good 78 403 800 cfm QJet core, Everyday Performance is very reasonable, did a nice custom tune, runs great with my custom cam from Cutlassefi . By the time I bought the throttle bracket for the 2004R trans, it was more expensive for the Street Demon 750. But you being in Europe without a core, which is $75 US, shipping, customs etc, the Street Demon makes more sense. Just by bumping the idle and adjusting the mixture screws should improve vacuum at idle. Let us know how the first drive goes.