700R4 and 3.08 gears robbing my engine?

[WarlVlachine]

Hello,

I’m kind of in a pickle. Just eliminating things at this point. I have an 86’ K10 that was 305 / 700r4 stock. Drove just fine until I dropped a roller 350 in front of it. The engine starts and revs fine, beautifully. I even timed it three times to be sure. It will idle in first and reverse, but when you accerate at all it bogs down hard and dies. One of my remaining thoughts is that the 700r4 and low gears might be conflicting with the engine.

The engine I don’t know much about. 350, cammed, votec heads, full roller. Probably around the 400hp mark. It seemed like a deal and still feels like it. Like I said, it runs perfect not under load.



I appreciate your thoughts.

 

[HotRodPC]

You mean tall gears, not low. Low gears would be like 4.10 or so. So if a weak Wee O Five drove just fine and now a 400hp 350 does NOT drive just fine and it's cammed and such, I'd say the cam and engine isn't built right for your trans and gear combo. It may be an engine that doesn't start making good power until mid range instead of low end and you certainly need low end grunt to get 3.08's and a 2 ton truck moving. But even with that, you should be able to do some tuning and get it to run. Do you have a choke on the carb? Are you sure the choke is off? How is the carb jetted? Maybe to rich? Could even be to lean. And here's the first thing I'd check since I'm not exactly quite sure what you mean or how sensative your acceleration is before it bogs and dies, but how long as this enigne set before you installed it and what carb is it? If it's a severe problem, it's most likely the acclerator pump in the Carb.

 

[WarlVlachine]

You mean tall gears, not low. Low gears would be like 4.10 or so. So if a weak Wee O Five drove just fine and now a 400hp 350 does NOT drive just fine and it's cammed and such, I'd say the cam and engine isn't built right for your trans and gear combo. It may be an engine that doesn't start making good power until mid range instead of low end and you certainly need low end grunt to get 3.08's and a 2 ton truck moving. But even with that, you should be able to do some tuning and get it to run. Do you have a choke on the carb? Are you sure the choke is off? How is the carb jetted? Maybe to rich? Could even be to lean. And here's the first thing I'd check since I'm not exactly quite sure what you mean or how sensative your acceleration is before it bogs and dies, but how long as this enigne set before you installed it and what carb is it? If it's a severe problem, it's most likely the acclerator pump in the Carb.

Right you are, tall gears. ‍I’ve tried two different carbs. The one that came on it was a 600cfm Edelbrock and I had a newer 650cfm edelbrock that I also tried. No choke for either carb.

I had to do some adjustments both times to get it to stop popping out of the exhaust, I wouldn’t say it was major adjustments from my experience with carbs. But that’s not much. Good vacuum as well, hangs around 15.

 

[rpcraft]

if your engine is bogging down its a tuning issue of some sort. 3.08's and a 700R4 aren't necessarily a recipe for bogging but it depends on what the tire sizes are. if you have popping in the exhaust then that is in indication you need to tune further. It might be a vacuum issue or intake leak.

 

[WarlVlachine]

if your engine is bogging down its a tuning issue of some sort. 3.08's and a 700R4 aren't necessarily a recipe for bogging but it depends on what the tire sizes are. if you have popping in the exhaust then that is in indication you need to tune further. It might be a vacuum issue or intake leak.

I definitely have good vacuum. I had to lean it up to get it to start popping I can try and link a video of it running, for the experienced ears.

 

[WarlVlachine]

You mean tall gears, not low. Low gears would be like 4.10 or so. So if a weak Wee O Five drove just fine and now a 400hp 350 does NOT drive just fine and it's cammed and such, I'd say the cam and engine isn't built right for your trans and gear combo. It may be an engine that doesn't start making good power until mid range instead of low end and you certainly need low end grunt to get 3.08's and a 2 ton truck moving. But even with that, you should be able to do some tuning and get it to run. Do you have a choke on the carb? Are you sure the choke is off? How is the carb jetted? Maybe to rich? Could even be to lean. And here's the first thing I'd check since I'm not exactly quite sure what you mean or how sensative your acceleration is before it bogs and dies, but how long as this enigne set before you installed it and what carb is it? If it's a severe problem, it's most likely the acclerator pump in the Carb.

I'm going to try and run it in 4 low. That should rule that out if I'm thinking correctly.

 

[rpcraft]

I guess it depends on your definition of bogging.

 

[RecklessWOT]

This thing isn't turbocharged or anything. Even though tall gears aren't great for acceleration, if a little 160HP 305 was able to get that rig up to speed, I see no reason an engine with more than double the HP couldn't get it moving, regardless of the way it's built. Even if you're making less power at lower RPMs it can't be much less than a 305. Gotta be something wrong with the way it's tuned

 

[bucket]

This thing isn't turbocharged or anything. Even though tall gears aren't great for acceleration, if a little 160HP 305 was able to get that rig up to speed, I see no reason an engine with more than double the HP couldn't get it moving, regardless of the way it's built. Even if you're making less power at lower RPMs it can't be much less than a 305. Gotta be something wrong with the way it's tuned

Exactly. Even if the 350 is built for high end power, the point at which it produces it's lowest output is still no less than the stock 305 was making at that point.

 

[WarlVlachine]

I see you're point. It's tough getting all spun around trying to get this thing running right, I'm sure I'm missing something simple.

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[bucket]

Sounds lopey

Can you drive it around easily for a bit so you can pull the plugs and read them? Still the same torque converter?

 

[WarlVlachine]

Sounds lopey

Can you drive it around easily for a bit so you can pull the plugs and read them? Still the same torque converter?

Same TC. I cant even make it 100 feet under acceleration. I can idle back and forth in the lot though. =/

 

[bucket]

So I guess if you were to power brake the truck, it would just stall?

 

[WarlVlachine]

So I guess if you were to power brake the truck, it would just stall?

From what I'm feeling while trying to drive, that's what I would guess. I could try.

 

[WarlVlachine]

Let’s get a slow clap going, for me using the wrong firing order. I had to pay a guy with his name and a pocket on his t shirt $200 to inform me. It all worked out in the end. Thanks all.