Inline 6 is really tired

['68OrangeSunshine]

First fix your brakes.
Try a tune up.
How old is the Pertronix? I don't trust them. [GM HEI is a better system and you can get replacements anywhere.]
A busted vacuum advance diaphragm might give those symptoms. Or jammed fly-weights in the distr.
Pull a compression check.

Then consider rebuilding the 292. Bore it .030 over and you get 296 cubic inches. You can get an upgraded cam. Think about aftermarket intakes for a 4 bbl carb. Clifford and Offy make them. Add headers.
GMC V6s were tank engines in their day, But finding parts is difficult for an engine that rare. Since your rig is already a 292 truck, stay 292.
Stock and aftermarket parts are available for the L25 Chevy engine.

['68OrangeSunshine]

Originally Posted by Asshat

I read other post, and some people changed the orientation of their carb; mine is a 1bbl, so I don’t think that would be it.

Wth the Monojet, it shouldn't matter -- just leave it stock.

When people hot rod their L6 to sport a four barrel, then there's some discussion. Some folks think the truck won't go forward properly if the carb is oriented sideways.
The other school contends that the carb should be aligned so the primaries open equally over both plenums for cylinders 1-2-3 and 4-5-6. Not primaries opening over 1-2-3 and secondaries over 4-5-6.
And some ''experts'' say it's too close to matter unless you're drag racing.
Personally, I don't mind a sidesaddle carb. In fact it's easier to tune it over the drivers side fender, than bellyflopping across the radiator. But it's a free country.

[Asshat]

Originally Posted by '68OrangeSunshine

First fix your brakes.
Try a tune up.
How old is the Pertronix? I don't trust them. [GM HEI is a better system and you can get replacements anywhere.]
A busted vacuum advance diaphragm might give those symptoms. Or jammed fly-weights in the distr.
Pull a compression check.

Then consider rebuilding the 292. Bore it .030 over and you get 296 cubic inches. You can get an upgraded cam. Think about aftermarket intakes for a 4 bbl carb. Clifford and Offy make them. Add headers.
GMC V6s were tank engines in their day, But finding parts is difficult for an engine that rare. Since your rig is already a 292 truck, stay 292.
Stock and aftermarket parts are available for the L25 Chevy engine.

Originally Posted by '68OrangeSunshine

Wth the Monojet, it shouldn't matter -- just leave it stock.

When people hot rod their L6 to sport a four barrel, then there's some discussion. Some folks think the truck won't go forward properly if the carb is oriented sideways.
The other school contends that the carb should be aligned so the primaries open equally over both plenums for cylinders 1-2-3 and 4-5-6. Not primaries opening over 1-2-3 and secondaries over 4-5-6.
And some ''experts'' say it's too close to matter unless you're drag racing.
Personally, I don't mind a sidesaddle carb. In fact it's easier to tune it over the drivers side fender, than bellyflopping across the radiator. But it's a free country.

Tune-up: Everything is new... plugs, wires, distributor, cap, rotor, Pertronix. And, the plugs look pretty good.

Compression check - I need to do this.

I can see the vacuum advance at the distributor is moving, when I rev the throttle, the vcuum advance is moving the distributor plate and linkage.

I don't want to just re-build the I6 - thinking about picking up a GMC 305E V6 - would rather rebuild that motor. I'm just wondering why mine is so sluggish.

Same thinking with the Offy intake manifold - if this motor is crap, why should I dump money into an intake or a new exhaust?

[MySons68C20]

You have been all over the board between LS engines to V-6 to?
I'm not trying to be a dick but at some point you have to make a decision.
I've been in your shoes so not casting stones here......
I would go small block V-8 and don't look back.
Just my .02 after a little tequila

[geezer#99]

Originally Posted by '68OrangeSunshine

Wth the Monojet, it shouldn't matter -- just leave it stock.

When people hot rod their L6 to sport a four barrel, then there's some discussion. Some folks think the truck won't go forward properly if the carb is oriented sideways.
The other school contends that the carb should be aligned so the primaries open equally over both plenums for cylinders 1-2-3 and 4-5-6. Not primaries opening over 1-2-3 and secondaries over 4-5-6.
And some ''experts'' say it's too close to matter unless you're drag racing.
Personally, I don't mind a sidesaddle carb. In fact it's easier to tune it over the drivers side fender, than bellyflopping across the radiator. But it's a free country.

Where do you find an offy with two plenums?
It’s all one one plane inside just like a single plane intake.

[Asshat]

Originally Posted by MySons68C20

You have been all over the board between LS engines to V-6 to?
I'm not trying to be a dick but at some point you have to make a decision.
I've been in your shoes so not casting stones here......
I would go small block V-8 and don't look back.
Just my .02 after a little tequila

I know, I am all over the place. Trying to get some opinions and pros/cons on which way to go. I’m on a budget, and just upset that my I6 can’t even cruise up a hill.
I have a 5-speed on the floor, so if I go with an automatic, I got extra setups to do fit that, plus getting a column with the shifter. I’d rather just keep it 5 speed, but want a decent motor that doesn’t bog-out on a slight incline.

[MySons68C20]

I'm just sharing what I would do....the crappy part is it costs money dang it Gina!! (joke lol)
It's your stuff and money but at the end of the day what do you want?
Personal question but how much do you want to spend?

[Asshat]

Originally Posted by MySons68C20

I'm just sharing what I would do....the crappy part is it costs money dang it Gina!! (joke lol)
It's your stuff and money but at the end of the day what do you want?
Personal question but how much do you want to spend?

My budget is about $1000. Probably not enough to rebuild a motor.

There’s a 305 V6 that I could pick up locally for about $300. If I did, I would probably just try and get it running and see how it goes. I wouldn’t mind taking a few months to get it rebuilt. I just don’t know a shop I can trust.

I think I might do the disc brake thing first - I have a cross member from a 74 C20, just need to buy a steering gear and PS pump/bracket.

Also, I have a chance to buy that 305 V6, which you don’t see everyday. So, maybe I should jump on that even if I have to let it sit in my garage for a while before popping it in.

I guess my patience is a little short. But, that’s another story.

[geezer#99]

You got 5 speeds.
Use them all to go anywhere.
If you need to run in 3rd up a long grade it won’t hurt the motor.
Changing to an automatic won’t help. Will be worse. An automatic uses about 25 to 50 hp to work. That’s 20-50 you can’t afford to lose.
A big 305 v6 isn’t worth it. Tuff trans hook up. Hard to find too.
I’d look for a nice sbc. Anything from a 283 to a 350.

[Asshat]

Originally Posted by geezer#99

You got 5 speeds.
Use them all to go anywhere.
If you need to run in 3rd up a long grade it won’t hurt the motor.
Changing to an automatic won’t help. Will be worse. An automatic uses about 25 to 50 hp to work. That’s 20-50 you can’t afford to lose.
A big 305 v6 isn’t worth it. Tuff trans hook up. Hard to find too.
I’d look for a nice sbc. Anything from a 283 to a 350.

Noted! Thank you! That is the kind of input I am looking for.

[geezer#99]

That big v6 might be only 300 but by the time you go thru it and spend a big chunk putting it in you’ll have likely spent more than double a simple sbc swap would be.
Have you tried more initial timing beyond the 14 I suggested?

[Asshat]

Originally Posted by geezer#99

That big v6 might be only 300 but by the time you go thru it and spend a big chunk putting it in you’ll have likely spent more than double a simple sbc swap would be.
Have you tried more initial timing beyond the 14 I suggested?

Not yet. I have been thinking about that though. I think I need to do that brake/cross member swap first.

[AcampoDave]

The 292 had a touch more torque that my stock 283 and I dont feel like my truck is gutless

[Asshat]

Originally Posted by geezer#99

That big v6 might be only 300 but by the time you go thru it and spend a big chunk putting it in you’ll have likely spent more than double a simple sbc swap would be.
Have you tried more initial timing beyond the 14 I suggested?

I believe it is pretty far advanced. Not sure if you can tell in this video.
The timing marks only go about 10 degrees from TDC.

https://youtu.be/plk1tsYjUwU

['68OrangeSunshine]

Originally Posted by geezer#99

Where do you find an offy with two plenums?
It’s all one one plane inside just like a single plane intake.

I didn't. But I think the alignment over center is more important than the Fore-and-Aft School.

['68OrangeSunshine]

My built 292 L6 has a lot more torque and power than the stock 350 in my '71 GMC [1998 crate]. But I put a lot into it.
Do you know what the mileage is? [Odometer not MPG.]
So if you go with a V6, LS, or V8, can I buy your 292 Passenger Side Motor Mounts?

[AcampoDave]

One thing that might be good is to invest in a dialback timing light. Then you could see how much advance you're getting from the vac can as well as the mechanical. It's a great tool to have and you will certainly make use of it again in the future. For my v/8 I bought a degreed tape for the balancer. Those are plenty cheap and do the same job but finding one for a 292 could be challenging unless the diameter is the same as a small block balancer.

[cwcarpenter98]

The stock, well at least I'm assuming it's stock, 283 in my 63 will slow down some while going up a hill in overdrive unless I give it more gas. In many cases, it is best to downshift so that you aren't lugging the engine. Any time that you're in overdrive, you are decreasing the amount of torque that the engine is putting through the drivetrain. Overdrive is a gear made for cruising. Drop into 4th (1:1) going up hills and you should be good if everything else is good on your engine.

What rear gears did you get with your rear end swap? That will have an affect on it as well, no matter what engine you choose.

Easiest swap is a SBC, but you do have to change your passenger side engine mount on the frame because the 292 is different. A stock SBC will work well with your t5. You won't have to swap bellhousings.

If you're gonna go LS, might as well set it up with the computer stuff so that you can take full advantage of the fuel. Probably going to have to change transmissions as well.

[geezer#99]

Originally Posted by '68OrangeSunshine

I didn't. But I think the alignment over center is more important than the Fore-and-Aft School.

You know if you want to correct the flow then a bit of experimentation with popsicle sticks and epoxy works.

['68OrangeSunshine]

Originally Posted by geezer#99

You know if you want to correct the flow then a bit of experimentation with popsicle sticks and epoxy works.

Sounds like an invitation to FOD.

[Asshat]

I did a compression check; all cylinders were 160-175.

Even going up a hill in 3rd gear is painful; no power.

[geezer#99]

Bump up that timing.

[AcampoDave]

Would there be some kinda heat riser flapper deal in the exhaust manifold that could be stuck shut blocking your flow?

['68OrangeSunshine]

Originally Posted by Asshat

I did a compression check; all cylinders were 160-175.

Even going up a hill in 3rd gear is painful; no power.

Those are real good numbers. Your engine is not tired. Something's out of whack. We checked for manifold leaks?

[Asshat]

Originally Posted by '68OrangeSunshine

Those are real good numbers. Your engine is not tired. Something's out of whack. We checked for manifold leaks?

Yes, several times.