I suppose if its an expert sharing, there's not much of a question being posed that needs any answering. That sharing may be recognized as mere rambling if the content is dry, technical and above the understanding of the reader. What's a better question or wonderment is why the experts bother to take the time to share.
I wasn't talking to you Joe, I KNOW you are an expert machinist and engine builder, because you told us on another thread. I was actually addressing 31vicky, and as usual, we mostly talk off-forum, because we don't wanna confuse you experts... Well, and every so often an "expert engine builder" posts on the open forum about using 327 pistons in a 301, and we pm about that too, right 31vicky??
There not experts George. They thought my reasoning for using .060 over 327 pistons in a 283 block to improve ring sealing was unorthodox. Or was it 396 pistons, I always get those mixed up.
Hey, putting the piston 1/8" in the hole helps with the gas you guys have down there, right Doug?? And if you run that with a 30/30, you can save weight and replace the starter motor with a hand crank...
The whole problem is. The man wants to build a motor for a tow vehicle Suburban. And a SBC is not the way to go. Nobody has given him a cheep alternative that will last. Except for me and another poster. Diesels, BBC, conversions are big money. Maybe 460 Ford
I missed the party the first go around, I just found this thread last night and read about half of it. Picked it up again this morning and just when it was getting interesting it petered off into mindless drivel. Thanks for the comments and the dyno sheets. Always trying to learn.
Going along with the fellow with the tired '91 350 pickup, my '85 Dodge pickup had a weak 318 from the get go. I put over 200,000 on it towing a race car and trailer. Weight was around 5500 with all the extra supplies needed for racing. It would pull all day long, not diesel fast, but I always got to where I was going. The truck had a 3.21 gear with 31" tires, 727 transmission. In the quarter mile it would run mid 19 seconds, so no real power or torque. I switched to a 440 for a while, the gas milage fell to about 8, but it did pull hard!
That's exactly what I was referring to. When I was towing that trailer with the '59 on the back, I had a near-death experience coming down a big hill on I-80. That Suburban is only a 1/2 ton chassis, and my exit was approaching. I started to slow as I approached the exit but it quickly became clear that I was not slowing down fast enough. I stepped into the brake harder, nothing but fade. Then the front wheels locked and we were along for the ride. I pulled my foot out of the brake and bypassed the exit, but not before needing a change of undergarments. The point I was making is that pulling the load is only half of the problem. Stopping it and steering with it is the other half. And if you can do one but not the other, you shouldn't do any of it. So we can sit and debate how much power you can get out of a SBC for torque, the OP could put a locomotive engine in his truck, if he can't stop the truck and trailer with a load on it it's useless.
Here it is. BUILDING A TORQUE SMALL BLOCK. It's going to cost BIG money to build a torque sbc. That a bigger just rebuild motor will do.
Diesel's superior torque. Normally aspirated Navistar 444 CID 7.3 liter V8 as used by FORD up until 1994 or so. 4.18 inch stroke. 338 lb-ft of torque at 1800 rpm That is 0.76 lb-ft per cubic inch Caterpillar 1140 and 1145 : 522 CID bore 4.5", stroke 4.1" 1140 (V-150): 150 hp @ 3200 rpm, 309 lb/ft tq @ 1700 rpm 1145 (V-175): 175 hp @ 3200 rpm, 353 lb/ft tq @ 1700 rpm That is 0.68 lb-ft per cubic inch at the peak Now those may be real industrial ratings of actually installed engines. ================== The 383 SBC dyno charts in post 56 both had over 400 ft lbs at 3000 rpm. 1.044 ft-lbs per cubic inch The "correction factors" and test installation might make installed power and torque a good bit lower, but still.............. I think it takes a turbo for a diesel to squirt out more than 1 ft-lb per cubic inch. Plenty of magazine tests claim way over 400 lb ft for 350 engines at some very streetable rpms.
Well, I've done some pretty good pulls with a 350,,, it just takes a little longer to get there.But like one of my friends pointed out to me. If you are pulling a heavy load up a long grade, at least a diesel doesn't sound like its going to blow up. Now that we have all helped B.A.King , all he has to do is make up his mind. He has probably gone for some aspirin.
Wow, how did any trucks tow trailers with 6 cylinders...mercy..I guess that 235 I had in my '59 PU, was on steroids? I did have to go into 3rd over Donner pass when bringing back a '48 F1 on a car trailer...coulda stayed in 4th with a 78 stock 350 I bet..lol. Ya...if you tow anything, you need a Big Inch gas engine or a diesel...ya...ya have to.
===================== Fir SURE don't want to end up stranded in Donner Pass. https://en.wikipedia.org/wiki/Donner_Party
Long arm. 12 and 16 Cads, Lincolns, Packards, Duesies. All long arms. Tons of torque! Used to work on 12 Cads. Idle at 450. Pull the****hole out of China. Needed it to push that tonnage around. Most inline sixes are long arms so hence tons of torque. They don't breath hard if in the right gear.
What you're missing is the RPM that the torque is rated at, 1800 rpm on the Navistar and 1700 rpm on the Cat. There is something that diesel engine mfgr's and users talk about, and that is Torque Rise. I.e. the increase in torque potential as rpm's decrease due to applied load. This makes all the difference in the world. The gas engines produce peak torque at far higher rpms, and have far smaller torque rise. For hauling a heavy load that makes a huge difference. You need a lot more gears and you need to keep the engine running much higher speed to achieve the same performance. That puts more stress on everything, including the driver, and uses far more fuel. The diesel engines pull much better far lower in the rpm range, so they get a heavy load up to speed faster, than when you hit a hill they maintain their work potential far better, as the rpm's drop they settle into their preferred torque range, it's a beautiful thing. Anyone who's spent time driving a truck or towing a large trailer knows exactly what I'm talking about. Face it, once they started putting diesel engines in pickups gas engine use practically disappeared for towing applications. That's true for the reason's above. Low rpm torque peak, and torque rise. That and the fact that the aftermarket is brimming with go-fast parts for those Navistar and****mins engines. I have 2 words for you: Gale Banks....
Okay, nice...I have an LS5 out of a '70 Vette, tad warmed up, in my '57 Chevy PU...will pull too...also, just sold my Transfers ('79 Pete, 400 Big Cam, changed a few things, was warmed as well)... My point is/was, you don't need 500 ft/lbs of torque to pull a trailer...and that 235...heck, could it have had 200 ft/lbs of torque? Heck, the OP just wants to*****e up his tired SBC to pull his trailer/cargo.. He doesn't need a****mins, Duramax, etc... Sure, a bigger, badder engine would be nice...but really needed for a twice a year excursion?
I know were are going "way off HAMB here"...but not really a true statement...one of my pull rigs is an '83 Chevy PU with the 6.2 Diesel, on it's 3 engine BTW,,,GM up graded in the later 80's, early 9i0's to a 6.5...may have been turbo'ed as well, don't recall...but, point is during that time a BBC (speaking in just GM terms here) would out pull them all, sans Turbo, with a touch of work. I think Dodge came out in the early 90's with the "pulling" trucks,,,and the rest (GM/Ford) followed suit. Sure...a new-ish (post 90 or so) diesel is a better tow rig..no doubt, but as it pertains to this thread...not relevant
I think the thread has moved beyond the OP's requirement into theoretical discussion about torque in general, and the Cadillac guys are reminiscing about their beloved Caddies. Ham friendly? The whole damn thread is OT, it's about an 86 Suburban fer chrissakes... Chevy 6.2 was a dog, everyone knew that. It was the Navistar/Ford and****mins/Dodge engines that ruled the world. Chevy's were a joke. It's relevant only to the extent that if we're gonna talk about swapping engines for the poor guy who started this thread, than a Navistar or****mins diesel would make a lot of sense. It seems the thread has moved beyond answering the question of the OP into a theoretical discussion about torque in general, while the Cadillac guys are having fun reminiscing about their beloved Caddies.
Don't think the guy is looking for the expense of a diesel conversion. Wanted opinion on building a torque tow engine. The SBC is not the way to go. 502 crate or the Cad conversion. Approximate cost about the same. Cad is better mileage. Now we haven't heard from him. Probably because everybody went off into the stratosphere. Ya think he might have wanted an opinion a budget build that would last?
Actually, what the OP said was the engine was going to be a 350. Here, let me quote him: "Its time to build motor for off topic tow vehicle. It will be a 350. There is lots of small block knowledge on here,so.... I want to build torque! What head/valve size. What cam? It will have edelbrock performer and 600 cfm carb because i have had very good luck with these over the years." He did NOT ask what engine to build a torque motor. He already said it would be a 350 Chevy and was inquiring what head/valve size and cam to use with an Edelbrock Performer and a 600 cfm carb. At least 2/3 of the responses on the thread went off into the stratosphere when all he wanted was opinions on how to build a 350 with some torque. No where did he ask, "What engine should I put in my Suburban?" He already told us it was going to be a 350. And in case you missed it, he said it was going to be a 350.
Look back. My first response was advising against the sbc and going with something bigger for torque/pulling.
This article might be helpful for building a SBC 350 with some torque http://www.hotrod.com/how-to/engine/1004clt-low-budget-chevy-350-small-block-engine-build/
Speaking for myself, I still believe in at least TRYING to teach a guy to fish, instead of handing him a dead perch...Call me an optimist... Early on, several of us advised him to build a 383, and explained why. Several have also advised him to use vortecs, I suggest them because the chamber will allow more cylinder pressure without detonation ion a given amount of octane compared to any other low $$ junkyard casting, and more BMEP = more torque, every time. I wont make cam or carb recommendations on the open forum anymore, too much********* ensues.
The Jalopy Journal
