Back on topic. No one cares about the proper use of torque and we all know what is being conveyed.
I am interested in this as my new to me 54 Ford truck is basically a 87 350 TBI Suburban. I got some long tube that I will be running to a Ford Lightning Muffler (2 in 2 out). Just checked out the "salad bowl mod" as well as throttle body mods and spacers.
Found any cheap places to get a high torque cam and this intake you speak of?
unevolved wrote:Zomby woof wrote: And I always thought it was lb/ft. Let's just call it Newton meters and be done with it.According to textbooks, yeah, that's the correct way. It's still pronounced "foot-pounds" but it's really pounds per foot of moment. I vote we move to slugs/yd. Otherwise known as "yard-slugs."
While you will see a textbook with lb/ft, it's totally different, and pronounced pound-foot.
I know this because I once got embarrassingly hosed making a similar statement.
Whoops, made this before Greg's post. Carry on, folks!
The TBI unit is the heart of any problem when improving a TBI engine. The TBI units is a pretty close to a 2-barrel ~600cfm carb.
In order to improve a TBI 350, it need to breath better. There is a list of mods to the TBI that will improve air flow in to the engine. CFM Tech is a great source of info for TBI improvements.
Addidionaly join Full Size Chevy for more tech about your truck and wonder around GMT400.com for more hard-core tech abour the GMT platform.
http://www.cfm-tech.com/index.htm
http://www.fullsizechevy.com/forum/forum.php
http://www.gmt400.com/forum/
Also, I owned a 95 Yukon GT, and they're great trucks that last for ever if you take care of them. I inten to get another after i graduate college this year.
HiTempguy wrote:MG Bryan wrote: Haha. You're an ME aren't you?I sure hope not..
Ouch. Got me. That's what I get for being sloppy, you're completely right. I was thinking lb*ft. This is embarrassing.
DReilly582 wrote: The TBI unit is the heart of any problem when improving a TBI engine. The TBI units is a pretty close to a 2-barrel ~600cfm carb. In order to improve a TBI 350, it need to breath better.
IMO this should be your last upgrade. I’ll say it one more time. Most people overestimate the CFM requirements of their engine. For a more accurate estimate, use the Wallace Racing CFM calculator: Wallace Racing - Intake CFM Requirement. I like it because it also takes into account the type of intake manifold. Engine CFM requirements highly depend on the Volumetric Efficiency (VE) of your engine at red line. It automatically calculates the compensatory 120% to 150% of the engine's base requirement using the dual plane intake. If you were to use a single plane intake (yes one exists - the Edelbrock MPFI unit is a single plane design), the percentage over the engine's base CFM requirement is between 110%-130%. Most factory engines are between 65-75% VE at redline. On a mildly upgraded 350 engine (i.e. headers, exhaust, chip) with stock heads and cam, the VE hits about 72%. If you were to change cams, you're looking at about 78% VE. Change heads and cam, about 85-88% VE. Stock TB cfm on a 350 engine is 490 cfm at 1.5inHg. Redline on the stock engine (or mine at least) is 4500-4750 RPM. Like I said before, the stock engine's VE is about 66%. Input the numbers into the calculator and what do you get: 381 to 476 cfm. So that's why the engineers at GM chose the size of TB that they did. Now let's now say you've changed the cam plus all the other performance goodies, redline now at 5000 RPM, stock heads, VE now at 78%: 474 to 592 cfm required. You could still use the stock TB easily with no major bottleneck in power. Ultimate TB mods would give you 520 cfm. Even with a cam change and other performance goodies, the stock TB is still pretty decent. You could upgrade to the CFM-Tech unit rated at 590-620 cfm if you wanted to. What if you changed heads/cam now and redline at 5600 RPM, VE now at 88%: You'd need 613 to 766 cfm. The CFM-Tech TB would work, but the larger 50mm TB would be better. It's rated at 690-750cfm, depending if you believe the upper figure quoted by XtremeFI or not. The 454 TB (also 50mm) is rated at 670 cfm at 1.5inHg w/o the injector pod according to airdeano's tests. I'd tend to believe airdeano's numbers more because they're pretty bang on: http://www.fullsizechevy.com/forums/...d.php?t=145234. A 383, stock heads, with cam, Redline at 5000 RPM, VE again at 78%: 519 to 648 cfm. Either the CFM-Tech or XtremeFI TB would work. The stock TB even with the ultimate TBI mods (520 cfm) would be too small IMO. The bottom line is: calculate the CFM requirements of your particular engine. Most likely, you won’t need to buy a larger TB unless you’ve made extensive upgrades to your engine. The ultimate TBI mods are relatively easy to do yourself and will increase your TB airflow to about 520 cfm. More than enough to support your performance upgrades. (Note that the required cfm of your engine has nothing to do with hp!!)
This would disagree with you for most applications. Yes, the TBI Ultimate mods (being virtually free) are a no brainer, even if you don't really need them. But more airflow per say is not the answer. A higher quality of airflow, I can definitely agree on.
HiTempguy wrote: per say
http://en.wikipedia.org/wiki/Per_se 
Zomby woof wrote: http://en.wikipedia.org/wiki/Per_se
I'm on a roll eh?
Why not just change the rear gear? Seems like it'll be way cheaper and it will increase the torque at the tires.
thatsnowinnebago wrote: Why not just change the rear gear? Seems like it'll be way cheaper and it will increase the torque at the tires.
a weak engine with no torque is still a weak engine with no torque when you put deeper gears behind it.. and a Z71 means it's a 4X4, so that means you are trying to find deeper gears for both ends of the truck..
novaderrik wrote: a weak engine with no torque is still a weak engine with no torque when you put deeper gears behind it.. and a Z71 means it's a 4X4, so that means you are trying to find deeper gears for both ends of the truck..
Plus, being able to cruise/tow in OD with prodigious tq's ( 
) leads to good mpg. I mean, realistically, why wouldn't I just use smaller tires? Much easier to cause a drastic change in final drive, plus cheaper tires to boot. Z71's use ginormous 265/75R16's, pretty easy to drop down to a 245/75R16.
Have you ever driven a smog era 4x4 chebby 454 with a 4 speed and 4.88's? Still terrible at everything.
I was just really curious about how much tq I could make before getting serious (pulling heads, porting and polishing stuff, etc). It's a truck for towing and it was FREE, I'm not dumping $2k into the motor. As much torque as cheap as possible is what I'm after!
HiTempguy wrote:novaderrik wrote: a weak engine with no torque is still a weak engine with no torque when you put deeper gears behind it.. and a Z71 means it's a 4X4, so that means you are trying to find deeper gears for both ends of the truck..Plus, being able to cruise/tow in OD with prodigious tq's (
going from 265's to 245's won't do much to help your torque- in the real world that's not even a big enough change in diameter to throw your speedo off, and around here at least the 265's tend to be a few bucks cheaper than the 245's and are usually a little heavier duty tire.
the other weekend i was towing an 18 foot car trailer with a 97 Monte Carlo on it with an '06 Chevy 4X4 1500HD WT with a 5.3 and 3.73 gears.. even going into a 30mph headwind, it would just plug along in OD at under 2000 and not complain or downshift when going up hills. when the mileage was checked after we got back from the 290 mile round trip(unloaded on one leg, loaded on one, and even with some gas expended getting stuck in the guy's yard trying to bring the trailer back) it averaged 12.9mpg.
i was impressed.
i did virtually that same tow with a TBI 350 with 3.42 gears once same trailer, same distance, 87 Monte SS on the trailer) and even without the headwind it would never shift into overdrive. i never checked the mileage on that trip, but the gas gauge told me it used almost twice as much fuel and that truck unloaded and driven nicely never got over 14mpg.
novaderrik wrote: going from 265's to 245's won't do much to help your torque- in the real world that's not even a big enough change in diameter to throw your speedo off, and around here at least the 265's tend to be a few bucks cheaper than the 245's and are usually a little heavier duty tire. the other weekend i was towing an 18 foot car trailer with a 97 Monte Carlo on it with an '06 Chevy 4X4 1500HD WT with a 5.3 and 3.73 gears.. even going into a 30mph headwind, it would just plug along in OD at under 2000 and not complain or downshift when going up hills. when the mileage was checked after we got back from the 290 mile round trip(unloaded on one leg, loaded on one, and even with some gas expended getting stuck in the guy's yard trying to bring the trailer back) it averaged 12.9mpg. i was impressed. i did virtually that same tow with a TBI 350 with 3.42 gears once same trailer, same distance, 87 Monte SS on the trailer) and even without the headwind it would never shift into overdrive. i never checked the mileage on that trip, but the gas gauge told me it used almost twice as much fuel and that truck unloaded and driven nicely never got over 14mpg.
But you are talking about a stock TBI vs a stock 5.3. I'm not disagreeing a stock TBI is a turd, even with a supposed 300ftlb's at 2800rpm. 
My dad's 1/2 ton crew 4x4 with the 5.3? We did 15mpg towing 6000 pounds from Oregon to Alberta. Cruise set at 100km/h. Nothing to sneeze at at all!
3.42's vs 4.10's, all else equal, is a difference of over 10mph at 2000rpm (66mph vs 78mph), and driving in 3rd the whole time would be 55mph with a 235/75R15 (standard 2wd chev tire). So, presumably, the TBI made weak suck torque at 2000rpm.
Because the truck is going to be lowered 3" all around, I'm thinking more like a 235/65R16. Not really any cheaper, but that would make the equivalent (or close to) of going to a 4.88 gear.
Edit- BTW, I'm really enjoying this discussion, me arguing strongly against you is not because I feel you are "wrong"! It's really got me thinking about a lot of things...
lb'
pounded feet
so my 94 burb has a 350 tbi. bone stock 170k mile truck, 4x4, 245/75/16 tires.
i tossed a w body grand prix on my 2000# flatbed trailer yesterday. i barely felt the car/trailer. it wanted to cruise in OD at 55 no problem, but i strongly believe in not towing much in OD with a 4L60. i roasted one towing an empty trailer on the highway.
not sure what the point is, but i do not feel the need for more units of torque
What about mpg? Typically, more torques (all other things staying equal) hopefully means a more efficient engine, which means better mpg's. When we talk about a truck getting 12mpg towing, and you can make it get 14-15 towing, that's a huge savings.
Towing in OD is fine, like I said, we've (father and I) have had three 700R4/4L60E/4L65E transmissions survive 1 million kilometers of use as trucks. The 4L60E clutches are a known weakpoint, luckily, my tranny is being rebuilt to survive towing in OD so that is not an issue (upgraded to 4L65e specs plus better clutches). The best way to roast a tranny is to tow without the converter locked up, so YMMV.
HiTempguy wrote:novaderrik wrote: going from 265's to 245's won't do much to help your torque- in the real world that's not even a big enough change in diameter to throw your speedo off, and around here at least the 265's tend to be a few bucks cheaper than the 245's and are usually a little heavier duty tire. the other weekend i was towing an 18 foot car trailer with a 97 Monte Carlo on it with an '06 Chevy 4X4 1500HD WT with a 5.3 and 3.73 gears.. even going into a 30mph headwind, it would just plug along in OD at under 2000 and not complain or downshift when going up hills. when the mileage was checked after we got back from the 290 mile round trip(unloaded on one leg, loaded on one, and even with some gas expended getting stuck in the guy's yard trying to bring the trailer back) it averaged 12.9mpg. i was impressed. i did virtually that same tow with a TBI 350 with 3.42 gears once same trailer, same distance, 87 Monte SS on the trailer) and even without the headwind it would never shift into overdrive. i never checked the mileage on that trip, but the gas gauge told me it used almost twice as much fuel and that truck unloaded and driven nicely never got over 14mpg.But you are talking about a stock TBI vs a stock 5.3. I'm not disagreeing a stock TBI is a turd, even with a supposed 300ftlb's at 2800rpm.
i was trying to say you need to just swap a 5.3 into it and not throw any money at a TBI trying to make more torques..
How much is an adjustable cam gear and one of those timing covers with the windows for a SBC?
Im thinking gasket set, decked heads, intake, cam, ^those parts, and some home-brew tuning might get it close to 400 tq. Or at least beat the stock torque number at an even lower rpm.
Vigo wrote: How much is an adjustable cam gear and one of those timing covers with the windows for a SBC?
slightly less than a junkyard 5.3..
Greg Voth wrote: Found any cheap places to get a high torque cam and this intake you speak of?
I totally missed this part of your post. It really depends on HOW MUCH OF A CHEAPASS YOU WANT TO BE. Now, I am one of the cheapest sons of bitches around, but I've learned (the hardway) that sometimes I should spend more money to be cheaper in the long run. It's part of the reason I hummed and hawed so long over whether I should shell out the $200 (trailer rental and gas) to pick this truck up, and then spend another $1500 getting the tranny rebuilt.
So, the cheap version is this:
Melling torque cam with new lifters. Cheap. The specs are not as aggressive as the CompCam I was recommended BY CompCams, so as long as you don't rev the truck over 4500rpm you should be able to get away with the stock valve springs. Still have to double check that. In case valve springs are needed...
Yes, 99C plus shipping 
If you're replacing the cam, you'd be r-tarded to not do the chain and gears.
That cam has been shown to have SOLID improvements over the stock cam. However, the CompCam (with lifters) is only $149.99. When all is said and done (plus shipping) you are looking at $180 to do a cam swap with everything new on the cheap.
Or, you can do this ($360cdn for me, or around $310US for you guys after shipping):
http://www.ebay.com/itm/Comp-Cams-K12-249-4-Chevy-XE249H-305-350-computer-/220943486774?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item3371420f36
It comes with the cam CompCams recommends to make as much torque as low as possible (the specs I sent them included long tubes and true duals, an Edelbrock TBI intake, and custom tune). It also has their double roller chain and sprockets, new springs, and new lifters.
Edit- Realistically, I am fine spending $1k (cam swap, intake, true duals, custom tune) on a free truck that has essentially been in the family for over a decade so it is a well known variable. That to get the performance to a good level, plus $1500 tranny rebuild means I have a truck that should go for another 250,000kms all for $2500. Pretty reasonable.
Thanks for the info!
I am torn between working with this motor which reportedly has 110,000 miles of unknown history or just doing a 4.8 or 5.3 swap.
+1 on the fullsizechevy.com forum recommendation, search for posts by "airdeano" related to TBI. There are some hard limits on the TBI motors, and it can get expensive to make monster HP out of them. They have a bunch of torque down low, and it's easy to enhance that characteristic.
I had a TBI 350 for years and did a ton of research. What worked well for me was a TBI spacer and a catback exhaust. I had purchased more of the CFM-tech stuff, but never got a chance to install it.
One point is that the TBI 5.7 and the 4.8/5.3s are totally different motors. The TBI has a ton of torque down low, and runs out of breath by 4K RPM. The 4.8/5.3 have a bunch of torque, but the majority of it comes on strong in the mid-range, not down low.
Greg Voth wrote: Thanks for the info! I am torn between working with this motor which reportedly has 110,000 miles of unknown history or just doing a 4.8 or 5.3 swap.
A 4.8 or 5.3 swap is going to cost you at least $2k IMO once you get everything up and running. A brand new TBI ready short block from GM? Something like $1300 LOL! Bolt your heads on (or if you are feeling spending, bolt assembled vortecs on), and you have a brand new motor for under $2k that with a cam will make over 350ftpnds and close to 250hp.
As dj pointed out (and as I alluded to previously) the newer 4.8's and 5.3's are part of the fuel efficiency/hp wars. No torques, cause torques don't sell. Yea, the 5.3L pulls like a dream (and is silky smooth) to 6k rpm, but off idle to 3k is deeeeaaaaaaad, even with tq management removed.
Thanks for the link and name dj, I'll do some more reading!
Those cams you linked to are pretty mild. Since I haven't worked on small blocks for some time, I'll assume yours still has the stamped 1.5 rockers. For a nice increase on the cheap, get a set of 1.6 rockers. You'll pick up a few degrees duration, and add about .030" lift. n the milder cam, that would put your exhaust lift at about .472, just where you want it on a small block (unless those heads are different than the ones I'm used to). You may even experiment with having them just on the exh. Sometimes that works wonders. Your stock springs will be fine.
you want to cam it so she's out of breath at 4000. a cam that will do that is a cam that will pull stumps
In reply to HiTempguy:
I am in midst of an LS1 swap into my RX-7 so I have a decent idea of whats needed.
I can get a 4.8 or 5.3 complete engine, trans, computer etc. here for $800 pretty easily. However I will have no idea of its history. It will probably be a couple hundred dollars to get it running which I can offset by selling the motor and trans in it.
My goals are different for the truck as I do not intend to tow very often and only locally if I do. (4 hour radius). It will mostly be a street driven.
I am however interested in upgrading it on the cheap as it sits if possible. I've already got the long tubes and exhaust figured out. Besides a nice torquey motor sounds fun.
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