SBC 383 500ft/lb torque build

[mtmvette]

B Original thank you very much for your help. The old time engine designer gave me information and I sourced parts accordingly:

350 30 over

3.75 stroke

5.7 rod

12cc 1.425 compression height pistons

0 deck true parallel to crank axis

.039 to .041 gasket

EQ CC167ES2 heads 76cc 2.02 1.60

CompCams X4258HR 1.5 rockers

Edel RPM performer Air Gap

650 - 750 cfm carb

Pump 87 octane

600 - 800 idle

I have sourced a roller block. Calculations come to approximately 9 to 1 static? Maximum torque in 2500 to 3500. I don't know if you can use the 5252 rule for horsepower? Cam timing may need to be retarded 4 degrees. Not sure need to play with that. Again thanks for your help.

[groberts101]

Post away I have a copy of David vizard torquemaster I build a dozen engines off have it it's been spot-on with a predictions every time. It is way beyond the inferior programs like desktop dyno

How does one get that? How much is it?

Unless you hang out at Terry Walters machine shop. You have to attend one of his seminars in Charlotte. He gives it and the porting software (IPO) away for free as part of the seminar. The software is still in evaluation form it is complete for Gen I SBC's and near complete for SBF's but he still has a lot to go before the other engine groups are done before he can release it for sale.

Carnut know a lot more than I about the Porting software he has been posting post for a couple years about it
I know this is may be off subject but here is a video on the porting software I think there may be one on the torquemaster somewhere but I cant seem to find it
https://www.youtube.com/watch?v=GaEvJykjH9U

Charlie had all that stuff posted and linked in his "port energy" thread a while back. Unfortunately, old minds don't necessarily like to be retrained or forced to change perspectives based on new software. Basically same stuff most already know, higher mass flow rates at increased velocities hits the cylinder and exhaust harder to increase torque and horsepower via improved inertial supercharging and exhaust scavanging effects.

As for all the other stuff about keeping overlap stupid low for fear of reversion and all the typical mumbo jumbo that gets tossed around?.. dead wrong, imo. With specific regard to the level of power the OP is trying to acquire here at such low rpm's.. it's all about maximizing velocities AND tuned lengths on both the induction AND exhaust sides to get there. Get those closer to tuned right with extra long runner tpi style manifold and longer tube headers(tri-y, smaller prinary, stepped 4-1 with very small choke, or whatever) and you can increase the valves velocity profile on both sides without all the nasty negative side affects. Which despite still having shorter seat duration numbers then naturally increases the degree of overlap all on its own.

And adding more compression into the mix gives stronger pulses in the induction and exhaust to allow larger lifts and more duration to be used without excessively increasing reversion and killing low speed torque production. That in itself helps reduce end gas contamination via added inertial ramming and increased exhaust scavenging to help reduce detonation potential.

At the end of the day.. if it really was so easy to make 500 ft/lbs at 3,000 rpm with a low budget 383" 9:1 compression dual plane carbureted 87 octane motor stuffed into a cars engine bay?.. there would be far more people doing it. And then the need to rev motors harder and spend much more money on stouter shortblocks and valetrain typically required to do it would definitely be diminished. Most people don't spend all the extra money because they want to.. but because they are forced to for gaining those improved torque and horsepower results. The need is there.. it's just not as easy and cheap as it's being made out to be.

[groberts101]

B Original thank you very much for your help. The old time engine designer gave me information and I sourced parts accordingly:

350 30 over

3.75 stroke

5.7 rod

12cc 1.425 compression height pistons

0 deck true parallel to crank axis

.039 to .041 gasket

EQ CC167ES2 heads 76cc 2.02 1.60

CompCams X4258HR 1.5 rockers

Edel RPM performer Air Gap

650 - 750 cfm carb

Pump 87 octane

600 - 800 idle

I have sourced a roller block. Calculations come to approximately 9 to 1 static? Maximum torque in 2500 to 3500. I don't know if you can use the 5252 rule for horsepower? Cam timing may need to be retarded 4 degrees. Not sure need to play with that. Again thanks for your help.

Why don't you post the cam specs rather than making us look them up for you?

I'll run it through pipe max too.

[groberts101]

B Original thank you very much for your help. The old time engine designer gave me information and I sourced parts accordingly:

350 30 over

3.75 stroke

5.7 rod

12cc 1.425 compression height pistons

0 deck true parallel to crank axis

.039 to .041 gasket

EQ CC167ES2 heads 76cc 2.02 1.60

CompCams X4258HR 1.5 rockers

Edel RPM performer Air Gap

650 - 750 cfm carb

Pump 87 octane

600 - 800 idle

I have sourced a roller block. Calculations come to approximately 9 to 1 static? Maximum torque in 2500 to 3500. I don't know if you can use the 5252 rule for horsepower? Cam timing may need to be retarded 4 degrees. Not sure need to play with that. Again thanks for your help.

Here you go. Better have top notch intake and exhaust with perfect tune to reach 105% VE.

mtmvette towing motor.PNG

Here's another with 116% VE. Never gonna happen if it has to go into an engine bay but gives you an idea anyways.

mtmvette towing motor 116VE.PNG

[Scotthatch]

Groberts101 does pipemax use runner length in the calculation? Also does it show peak rpm or just range?

The reason I ask is my math is showing a peak torque on the parts listed being closer to 3800 rpm .... with the heads listed at lift like 215 to 218 cfm flow .. I had to kinda guess on runner length and cross section of the intake since I don't have a intake handy

[groberts101]

Groberts101 does pipemax use runner length in the calculation? Also does it show peak rpm or just range?

The reason I ask is my math is showing a peak torque on the parts listed being closer to 3800 rpm .... with the heads listed at lift like 215 to 218 cfm flow .. I had to kinda guess on runner length and cross section of the intake since I don't have a intake handy

It's not a true dyno sim with pretty graphs. Just spits out peak numbers ranging from lowest to best.

It's main purpose is to help understand the resonant tuning affects for induction and exhaust lengths and at what timing each wave will typically arrive at... 2nd, 3rd, 4th order, etc. Hence the name Pipemax.

Here's the induction lengths.

mtmvette towing motor induction lengths.PNG

[Scotthatch]

Interesting ..

Thank you

[mtmvette]

groberts, I didn't know you were trying to help. I guess your helping to show me It "never gonna happen". ***Peak horsepower at 4000rpm. ***Retard camshaft 4 degrees. I would like to see the figures from of idle through 4000rpm but I guess pipemax does not do that. Scott - pretty impressive. Peak torque should actually be a little lower, more in 3000rpm range. groberts thanks for running the info. Also, thanks to these guys who gave me real user examples and a lot of good info: Carnut1, Headguy, Revtherory, englertracing, and B original. If you take a look at the info they provided with the engines they built, you will find they were all pretty close. I'm trying to build mine so the power will come in a little sooner. That's all. Oh, Scott, the Jmac engine seems like a good build, not alot of detail, but that is a pretty close example. Newbvetteguy I like TPI and you had alot of good info and I know those modified intake and runners produce serious low speed torque, but I'm not doing that to this truck and at this time. Probably in the future on another project.

[Carnut1]

I like the specs the old engineer gave you. It is funny the 383 built for torque in the old work truck went from ported swirl ports to ported afr 190's 2.055" / 1.625". Both ran well but I wanted more so I found a set of brand new Venolia flattops at a swap meet and built an Eagle H beam rodded 406 with the same afr heads and comp xe258 cam with 1.6 rockers. This 406 had high compression and was tough to tune also embarressed many others! That mill only liked 93 octane. I add this because the engineer speced a similar cam. Thanks, Charlie

[groberts101]

groberts, I didn't know you were trying to help. I guess your helping to show me It "never gonna happen". ***Peak horsepower at 4000rpm. ***Retard camshaft 4 degrees. I would like to see the figures from of idle through 4000rpm but I guess pipemax does not do that. Scott - pretty impressive. Peak torque should actually be a little lower, more in 3000rpm range. groberts thanks for running the info. Also, thanks to these guys who gave me real user examples and a lot of good info: Carnut1, Headguy, Revtherory, englertracing, and B original. If you take a look at the info they provided with the engines they built, you will find they were all pretty close. I'm trying to build mine so the power will come in a little sooner. That's all. Oh, Scott, the Jmac engine seems like a good build, not alot of detail, but that is a pretty close example. Newbvetteguy I like TPI and you had alot of good info and I know those modified intake and runners produce serious low speed torque, but I'm not doing that to this truck and at this time. Probably in the future on another project.

Sorry if I come off that way, I surely wouldn't spend any of my time explaining my viewpoints if I wasn't attempting to help. Too old, too busy and not nearly shallow enough for that kind of false pride massaging. Wasn't actually trying to dissuade you from moving towards your goal here.. only prepare you for the reality of the physics we all have to work with. So, not completely burst the bubble.. just shrink it up a hair more so it fits through the opening, is all.

So let me ask you these serious questions. You seemingly still expect to make somewhere even close to 500 at very low rpm but keep LOWERING the HP peak? Does that not push the VE requirement to achieve an expected power level even higher due to the now even slower piston speeds? And does the lower compression not hurt engine efficiency and cause slower mixture movement which could be detrimental to your cause?

The points I was trying to make above is that no amount of swirl from a Vortec head or old low flowing swirl port arrangement will save a motor with too large combustion spaces(lower compression) and moving the piston slower than is optimal to achieve inertial ramming and proper exhaust scavenge needed to achieve such a high VE. You're literally kneecapping this motors ability to get things moving well enough to provide increased VE. And at such low rpm peaks you'd literally need to shrink the exhaust port exit(which barely mates up with a 1.625" pipe as it is) to properly mate up to 14 gauge 1.5"(around 1.33" ID), or maybe even a 1.375"?.. 18 gauge(around 1.277"), to keep exhaust velocity really high. With the twisted and(now due to lower compression and rpm peak requirements) slightly too large and most definitely too short a runner design of the rpm air gap intake.. you'll need all the extra velocity help on the exhaust side of things that you could possibly get out of it.

And while I'm spending the time trying to help you meet your goal.. that cam is also a mistake imo as well. While spreading the lobe sep angles can preserve and separate cylinder pressures between both sides of the engines flow patterns, it will only hurt the ability for both systems to ram and purge the cylinder at such low piston speeds. Sure it helps prevent low speed reversion reduces the combustion spaces purge requirements.. but also limits the ability for a well designed intake and exhaust to really work their magic. By todays standards it's an average cam and will give you average power. If going with a roller cam I'd think you'd want to maximize it's potential benefit to your cause by increasing its lobe velocity allowance. Personally I'd be looking at a custom cam from Mike Jones or Chris Straub or any other favorite cam grinder of choice. That alone in conjunction with other well thought out and properly sized and lengthed components will be worth an easy 15+ ft/lbs in the range you're looking for here. It's not the biggest magic piece of the puzzle.. only the piece that brings the rest of a well designed puzzle together towards the desired result.

[Scotthatch]

Groberts101 I have a couple of questions for you

First you keep bringing up the high VE but isn't the point of ram tuning an engine is to get it to exceed standard VE at a given rpm ? Though I fully believe that all engines function on ram effect I do not think it is the wave tuning or pulse tuning as that would produce spikes in the dyno power curve at given rpms that I just don't see .. in relating steady state flow data to real dyno runs the math supports a given airflow as peak which would imply that when a engine reaches that airflow it will peak what we change is cross section and total flow to effect when rpm wise we reach that peak ....

Second .....at such a low rpm do you really think you are going to induce a charge draw on the intake with the exhaust side of the engine? The sbc engine tends to have such good ex flow that I can not imagine you worrying about incomplete blowdown of the cylinder...

Third ...... I completely agree that a longer runner would allow for a higher intake cfm flow number and therefore make more torque that the rpm he wants ... but wasn't the question more can it be done in the given package? As more cid or boost would also get it done

This engine is a fine line on airflow and rpm to reach the goal ...like I said earlier 200 cfm is kinda the tipping point with the given runner length ... the chosen head at lift is like 215 cfm ..... with a port efficiency of 85% (as I stated before and the chosen camshaft specs are that) that's a used cfm of 183 cfm .... which puts the peak torque at 3289 rpm ( my earlier post was in error I used 215 cfm not the correct 183 the cam gives you...it was late what can I say). Which makes this a 380 HP engine .... any more airflow or cam duration would move the rpm up with the given runner length .....

[FC-Pilot]

That alone in conjunction with other well thought out and properly sized and lengthed components will be worth an easy 15+ ft/lbs in the range you're looking for here. It's not the biggest magic piece of the puzzle.. only the piece that brings the rest of a well designed puzzle together towards the desired result.

I feel that is the key to this whole build. I am jumping in as I am putting together an engine for my sisters truck right now. It will be a fairly simple 350 with parts laying around in the shop, so we are leaving a decent amount on the table. I understand this. If you really want to meet a target you have to be willing to do what it takes to meet it. If you want guidance helping maximize the parts you have then you have to be willing to let the chips fall where they may. That is where I am at with my current build. I would love to see 410 Ft/lb's out of this engine. I know if I used different parts and started from scratch then I could do better than that by a long shot. I look at what advice has been given and some has been great. Now the question is how much of your goal are you willing to sacrifice to stick with the parts you have? For my situation, I am willing to lower my expectation as I know the collection of parts I have just won't get me there. The current parts you have listed won't hit your goal. That does not mean that it won't be a great running truck.

The funny part for me is this, if the engine makes an honest 400 Ft/lb's, I could tell my sister that it makes 450. With the fact that she had so little before with the current engine, she would believe it.

Paul

[B Original]

B Original thank you very much for your help. The old time engine designer gave me information and I sourced parts accordingly:

350 30 over

3.75 stroke

5.7 rod

12cc 1.425 compression height pistons

0 deck true parallel to crank axis

.039 to .041 gasket

EQ CC167ES2 heads 76cc 2.02 1.60

CompCams X4258HR 1.5 rockers

Edel RPM performer Air Gap

650 - 750 cfm carb

Pump 87 octane

600 - 800 idle

I have sourced a roller block. Calculations come to approximately 9 to 1 static? Maximum torque in 2500 to 3500. I don't know if you can use the 5252 rule for horsepower? Cam timing may need to be retarded 4 degrees. Not sure need to play with that. Again thanks for your help.

Here is what I came up with It appears that you have 9.07-1 compression with a 4.166 hole X .041 head gasket. I found that the best balance and bang for the buck was to shave the head about .020 and raise your compression to 9.3-1 to make this recipe.
Attached below the TorqueMaster spec sheet is a comp cams grind with Terry Walters part#. You can order it through him for the same price as a Jegs or Summit shelf grind. I looked at comp, erson, and and Comp lobe profile was the closest and least aggressive for longer spring life.

This grind is a 264 duration cam although the program specs a 263. The 263 is not a common lobe master profile so I think it is the better alternative. the compromise is 15.8" idle vacuum instead of 16.1" vacuum
This will have a small but noticeable idle rumbly quality but you will have a huge flat torque curve above 2000 and wont fall off much below that.

Now for heads will be fine although your's have a 167cc intake port volume. The alternative the program specs is a 150cc version. The trade off will be a modestly shorter torque curve at lower end of the RPM's and a few more horsepower at the peak and maybe a 100 rpm or so increase in the predicted peak. If your heads flow more CFM at lift, along with the higher lift of this lobe profile will make the Horsepower#'s modestly higher at peak.

383 torque motor speedtalk mtmvette.jpg

383 torque motor speedtalk mtmvett comp 1.jpg

383 torque motor speedtalk mtmvett comp 2.jpg

[B Original]

I recommend you cc the chambers and correct as necessary. The EQ combustion chamber can vary quiet abit. Compression is kinda critical when you want everything to work as predicted.

Reducing rotational friction can add Torque I prep the cylinders with a torque plate hone and a much finer wall finish that the 4oo stone leaves' along with a good 1.5mm ring set and piston (btw with the piston speed don't use a forged piston a good hyper coated piston if preferred) in most cases you can go from 25-30 lbs to 12-15 lbs thats good for at least 10-15 ft lbs

[Scotthatch]

That alone in conjunction with other well thought out and properly sized and lengthed components will be worth an easy 15+ ft/lbs in the range you're looking for here. It's not the biggest magic piece of the puzzle.. only the piece that brings the rest of a well designed puzzle together towards the desired result.

I feel that is the key to this whole build. I am jumping in as I am putting together an engine for my sisters truck right now. It will be a fairly simple 350 with parts laying around in the shop, so we are leaving a decent amount on the table. I understand this. If you really want to meet a target you have to be willing to do what it takes to meet it. If you want guidance helping maximize the parts you have then you have to be willing to let the chips fall where they may. That is where I am at with my current build. I would love to see 410 Ft/lb's out of this engine. I know if I used different parts and started from scratch then I could do better than that by a long shot. I look at what advice has been given and some has been great. Now the question is how much of your goal are you willing to sacrifice to stick with the parts you have? For my situation, I am willing to lower my expectation as I know the collection of parts I have just won't get me there. The current parts you have listed won't hit your goal. That does not mean that it won't be a great running truck.

The funny part for me is this, if the engine makes an honest 400 Ft/lb's, I could tell my sister that it makes 450. With the fact that she had so little before with the current engine, she would believe it.

Paul

Funny you should post this ... in doing the math this morning I was thinking that when it comes to torque I have not ever started with a clean sheet build ... I have done things in the past to boost torque on engines that are to high an rpm but that's more like patches then a correct build in that it was small runner intakes or small carbs ... even did a shear point at the head port entrance to reduce flow and agitate the fuel once....

Like you I tend to use what is handy and make it work ..the core I have sitting in the back of the shop that I was thinking about using for my shop truck is an old reverse flow lt1 and was debating what it's numbers would look like and what I could do to lower the rpm on it .. we get so hung up on HP numbers it's interesting to look at it so differently