Towing with a 305 V8?

[82sbshortbed]

I'll throw my .02 cents in. I'm in Texas and all that smog $hit is off both my squares. They don't care about that stuff. 7.50 for a SAFETY inspection. Get it off there imo. All those vacuum hoses and $hit drive me crazy. I have a quadrajet on my 454 with a 700r4 behind it. Took the air filter off so you could see I don't have 870 vacuum hoses everywhere for that other bs. Lol

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See how much less clutter is there? I got a vacuum hose for the vacume advance on distributor, one for transmission and one for pvc valve. And one for brake booster. Not 870 different ones.

Also have a 3.73 gm Trutrac 8.5 10 bolt posi rear end.
GM Chevy 8.5" Chevy 10-Bolt... https://www.amazon.com/dp/B01MRU3250/

Been a nice rear end. I broke the spider gears in the old 2.73 ratio stock one.

I know the 454 has more power but, if you switch out the rear end and if you do have a 700r4 with the low first gear I don't think you'll have a problem towing.

Now I do have a 84 long bed. I mean 84/85. It's like 220/221 whatever it takes....

Just kidding but it does have a 305 in it with ab th350 on it. Probably 2.73 rear end. But look no 89 vacuum hoses and smog bs either. Lol

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And this one has ac.

When I first put that rear end in the 82square, the th350 would rev to high in third gear. So that's why I put a 700r4 in for od. Now it's a great gear ratio between it and the 700r4. Great hole shot and od. Works in my book.

Good looking truck too and welcome from a fellow Texan. If you're in Houston you ain't too far from me at all. Maybe we could check each other's trucks out sometime.

 

[bucket]

Oh I forgot, I did not ever tow with mine. Sometimes some weight in the bed (like an engine and some parts), but never any driving like @SirRobyn0 does.

 

[CheemsK1500]

Just spit balling here, not arguing...

My '84 C10 had the original ESC 305 when I got the truck. I drove it everyday and recorded the mileage on every tank. After a while, I started having a bunch of troubles with the quadrajet, so I put on a 650 Holley that I had on hand. At that time, I also removed all the vacuum hoses and temp switches... got it down to a vacuum advance and a PCV hose. After a while longer, the pickup coil in the dizzy started to crap the bed, so in went a standard HEI. Pretty sure it was a Street Fire unit, but I don't remember now. I may have just stuck in a random HEI unit.

But anyway, the truck always ran great, didn't ping and the mileage was always the same. With a mix of city and highway, my average was 14.5 mpg. Best tanks were on long drives at 55 mph (no OD, 2.56:1 gear) which 18.5mpg could be achieved. The carb/dizzy situation didn't seem to make a difference.

My '84 K1500 has 305 that's been simplified like yours. It has an Edelbrock 1406, a sm465, and a 3.73 rear (and front). I have never recorded my mpgs, but the engine seems to work fine for it's age. I kind of want to toy a MSD spark control system, but I also kind of want to see what it can do in it's current state. Once I get a working fuel gauge, many questions will be answered.

 

[Ricko1966]

@bucket I cannot explain that,I have actually thought about it at length before. I wish I knew why some people get away with it and some don't, some of it is probably dumb luck. My situation my esc controller was acting up and died, well I have IDK how many Chevrolet HEIs here I grabbed one at random,stabbed it,hooked up vacuum advance,thats all,and drove it, when it was timed to have decent power,it pinged. So I hooked up the egr better but still pinged backed the timing off. It was a dog,played with springs,weights,and Vacuum advance cans and I actually have a 305 truck that will burn rubber,and doesn't ping,but there was so much trial and error involved,and actually now that I've got my stuff dialed in if I put esc back I may be disappointed with it. My gut says I'm still leaving some timing on the table. I am going back to esc because my gut says it will be better I will let you know after I do it,but I'm sure if I went back to esc I could add 5 more degrees initial. It is funny because there is a big mix of people that say they did it no problem,and others that fight and fight to try to get their trucks to run right again. Funny thing is on the hot rod f body sights they are retroing truck escs to msd boxes because they can run more timing with the esc. We want way they've got they want what we've got, the grass is always greener. I have a few more thoughts on why some get away with it but others can't but,I don't want to write a book here. Things that come to mind is what the trucks are being used for,what differences in gearing,age of the motor at the time. Honestly bucket IDK okay you were writing while I was typing,my trucks get used almost exclusively for towing. Like 90 percent if I can drive an econo box I do because I live so far from everything thus the push to get some mpgs so I can actually drive my trucks for than just work. Maybe I need to realize what works or doesn't work on one situation doesn"t mean it won't work in a different set of circumstances. Also when people say you need O.D. no I don't, everybody needs O.D. not me. It will never be in 4th gear cause I'm always pulling weight. I never explained that before.

 

[Velder]

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Did you rebuild this without buying a rebuild kit?

That is the before rebuild picture, here is the After.

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I bought a Hi-Grade brand kit, and followed the directions (what little there were). I think there might be a defect in the casting, that it doesn't fully compress the gasket. But yes I bought a rebuild Kit

 

[SirRobyn0]

Just spit balling here, not arguing...

My '84 C10 had the original ESC 305 when I got the truck. I drove it everyday and recorded the mileage on every tank. After a while, I started having a bunch of troubles with the quadrajet, so I put on a 650 Holley that I had on hand. At that time, I also removed all the vacuum hoses and temp switches... got it down to a vacuum advance and a PCV hose. After a while longer, the pickup coil in the dizzy started to crap the bed, so in went a standard HEI. Pretty sure it was a Street Fire unit, but I don't remember now. I may have just stuck in a random HEI unit.

But anyway, the truck always ran great, didn't ping and the mileage was always the same. With a mix of city and highway, my average was 14.5 mpg. Best tanks were on long drives at 55 mph (no OD, 2.56:1 gear) which 18.5mpg could be achieved. The carb/dizzy situation didn't seem to make a difference.

@bucket I cannot explain that,I have actually thought about it at length before. I wish I knew why some people get away with it and some don't, some of it is probably dumb luck. My situation my esc controller was acting up and died, well I have IDK how many Chevrolet HEIs here I grabbed one at random,stabbed it,hooked up vacuum advance,thats all,and drove it, when it was timed to have decent power,it pinged. So I hooked up the egr better but still pinged backed the timing off. It was a dog,played with springs,weights,and Vacuum advance cans and I actually have a 305 truck that will burn rubber,and doesn't ping,but there was so much trial and error involved,and actually now that I've got my stuff dialed in if I put esc back I may be disappointed with it. My gut says I'm still leaving some timing on the table. I am going back to esc because my gut says it will be better I will let you know after I do it,but I'm sure if I went back to esc I could add 5 more degrees initial. It is funny because there is a big mix of people that say they did it no problem,and others that fight and fight to try to get their trucks to run right again. Funny thing is on the hot rod f body sights they are retroing truck escs to msd boxes because they can run more timing with the esc. We want way they've got they want what we've got, the grass is always greener. I have a few more thoughts on why some get away with it but others can't but,I don't want to write a book here. Things that come to mind is what the trucks are being used for,what differences in gearing,age of the motor at the time. Honestly bucket IDK okay you were writing while I was typing,my trucks get used almost exclusively for towing. Like 90 percent if I can drive an econo box I do because I live so far from everything thus the push to get some mpgs so I can actually drive my trucks for than just work. Maybe I need to realize what works or doesn't work on one situation doesn"t mean it won't work in a different set of circumstances. Also when people say you need O.D. no I don't, everybody needs O.D. not me. It will never be in 4th gear cause I'm always pulling weight. I never explained that before.

In keeping with the theme of spit balling, I have a theory, or multiple thoughts to possible answers.

I will start with my experience.
I can run without the ESC, but I have to have no more than about 10 - 12 degrees of vacuum advance and I have to run base timing at 0.

A good functioning EGR valve allowed me to add in more vacuum advance.

A properly functioning ESC allowed me to run whatever the sticker says for base timing I think it's either 4 or 6 BTDC.

We are talking about 40 year or trucks here, and engines literally designed to have ESC system. So I think in the end there is variation in condition and wear that might make or break the ability to run without the ESC and have it be good or good enough. Since we know these motors were built to run on the razors edge of pinging all the time, the answer could even be as simple as manufacturing differences. Think about it. Valve timing, camshafts ect. wear or manufacturing differences. IDK just spit balling....

For me I saw improved fuel economy after getting the ESC working, but given how much I had to retard the timing without it, that only makes sense.

 

[Velder]

@SirRobyn0 Thank you for joining the thread!
What is your opinion on swapping the rear gears? If you had a truck with 2.73 would you go for 3.73 or 4.10?
My trailer is a single axle with electric brakes, but I understand your concern about it being a 1/2 ton. My dad won't pull with less than a 3/4.

 

[Velder]

@82sbshortbed That is exactly why I was even thinking about desmoging mine, all those hoses and connections drive me nuts.

 

[Velder]

@SirRobyn0 So you would advise that I keep the ESC and EGR? I had been planning on deleting them, but from what I gather that might be setting up for trouble.

 

[Velder]

What about If I were to replace my Qjet with a Holley? All of them say no EGR? Would that pose the same problem with timing?
I haven't even looked at my timing yet (still need to buy a light), but I intend to whether on the Qjet or Holley.

 

[Velder]

Just watched a few YouTubes on replacing Ring and Pinion gears. Looks a little more complex than I was thinking. In your Guys opinion, Is this something I should be capable of doing? or is this something requiring a lot of expertise?

 

[Trucksareforwork]

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We are talking about 40 year or trucks here, and engines literally designed to have ESC system. So I think in the end there is variation in condition and wear that might make or break the ability to run without the ESC and have it be good or good enough. Since we know these motors were built to run on the razors edge of pinging all the time, the answer could even be as simple as manufacturing differences. Think about it. Valve timing, camshafts ect. wear or manufacturing differences. IDK just spit balling....

This is the truth. It’s all user and engine condition dependent. I have followed your saga with ESC and tried to put mine back to stock and just found that it ran far worse with the esc restored. I run MOST everything stock except ESC, including my timing at stock set point (4 BTDC iirc) and the truck runs great for me FOR HOW I USE IT. EDIT: I DO NOT HAVE THE AIR PUMP SO I LIED ABOUT EVERYTHING STOCK... That means that it’s almost never under load because I just putter around mostly. When I do load anything into it I usually note some pinging right before downshift.

Mine is a 2.73 with 700R4. That means it already hunts around for the right gear plenty if I leave it in OD.

One note of caution to the OP: when I got my truck, the prior owner had completely hacked up the vacuum tubes because of “clutter” and “emissions.” What he had also done was leave a few vacuum leaks and disconnected some vital non emissions functions. Most important was the 700r4 vacuum kick down. He wondered why the truck surged and wouldn’t kick down (“that’s all broken”) Not everything operated by the vacuum lines is “emissions crap.”

Be logical in modding the engine. The 305 is a very different animal from any other SBC and definitely not comparable to a BBC when it comes to how much support the engine needs to run right.

 

[CheemsK1500]

Didn't the early 305s from the '70s not have ESC in the first place? Was there really enough substantial differences to make an '80s 305 ESC dependent?

 

[Rustisbest]

Get a timing light, make sure the advance weight holes aren't worn, use manifold vacuum and limit the vacuum advance, it's just another SBC. Crane no longer makes the advance limiter kit, but MSD makes one that easy to install. Both my vehicles are set up this way. I wouldn't tow a lot with one of these 1/2 tons without trailer brakes and a minimum 3.73 gears. Just my opinion.

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Good read here

HEI Tuning Secrets

 

[Trucksareforwork]

Didn't the early 305s from the '70s not have ESC in the first place? Was there really enough substantial differences to make an '80s 305 ESC dependent?

Lower compression in the early 305s. Early 305s were 8.5:1. Later ones were 9.5:1. Believe that made the difference.