350 Never seen one do this

[spectreblazer]

allright guys looking for some help cause this has got me stumped. in all the 350s i've seen i have never heard or seen one do this.

in gear 1,2, or drive the truck maxes out foot to the floor at 2500 rpm.

in neutral or park i could during the summer hit 5000 rpm no problem. now it is closer to 3500-4000 in the colder weather.

my setup is a turbo 350 transmission with a np 203. and 35" tires

i believe the gears in the front and rear are 4:10 so i know this truck should scream

my top speed is 67mph with my foot to the floor.

Things i have tried

holding 1st or 2nd to see if any increase in rpm. none

i took the truck mudding and had my foot on it all night. max rpm was 2500 rpm , never got stuck though

as far as i know this engine is stock. my truck had a 6.2L in it from the factory. then the 350 was put in it. i did not put it in.

i checked the kickdown cable and that was fine.

i plan to tear this motors top end down to replace an intake manifold gasket that i believe could be part of the problem but the truck was running the same before this.

my other thought is that i have a few cam lobes wore down and i can't build any power.

what do you guys think and have you ever head anything like this before in a 350? for the most part i've heard these motors are hard to kill

thanks 
-dave

[topp]

Was that tranny and Torque converter the one from the 6.2L?

[Lt.Del]

I don't know what you're driving....year? Pre '87 or post '86-- That way we can see if it is a carb or TBI

[spectreblazer]

its an 82 k5 blazer. the diesel had a 700r4 with it and i don't know what transfer case, but i'm 100% sure it had the 700r4. so the turbo 350 is from something else

according to the block number the block is a middle 70s 350 so it is carbed.

[Lt.Del]

does it run hot?
I ask because it seems there is a restriction, perhaps, in the exhaust flow. If that is the case, it would run hot since the exhaust will have a hard time leaving the engine. Do you have a catalytic converter on it?

[1980c10]

Check your throttle linkage and make sure your carb is achieving wot, also make sure your choke is fully open after the engine reaches operating temp. Do you see black smoke coming out your exhaust?
At 2500 rpm is the engine missing or bogging? any pinging?

[spectreblazer]

does it run hot?
I ask because it seems there is a restriction, perhaps, in the exhaust flow. If that is the case, it would run hot since the exhaust will have a hard time leaving the engine. Do you have a catalytic converter on it?

nope doesn't run hot. runs at 180-190

there are 2 cats on it but i believe both have been burned out. it's excempt from emissions

[spectreblazer]

Check your throttle linkage and make sure your carb is achieving wot, also make sure your choke is fully open after the engine reaches operating temp. Do you see black smoke coming out your exhaust?
At 2500 rpm is the engine missing or bogging? any pinging?

throttle is as WOT, the choke is electric so how would i check that?

no black smoke

at 2500rpm is is running pretty good. it sounds like that is all it has in it.

[Lt.Del]

the choke is easy to check, if you have no starting prrooblems, then it is closing fine.  After about 2-3 minutes of running, you can look at carb and see if choke wing is open all the way.

[zieg85]

To me it sounds like either your timing is way retarded, your exhaust system has a restriction in it or there is a fuel restriction like a kinked line or clogged fuel filter.  My $.02

[VileZambonie]

Put a vacuum gauge on it.

[spectreblazer]

To me it sounds like either your timing is way retarded, your exhaust system has a restriction in it or there is a fuel restriction like a kinked line or clogged fuel filter.  My $.02

timing is 8 degrees advanced right now

it was set at 23 and it ran alot better then it does now at 8.

i'll see if i can get ahold of a vac gauge. where should i hook it up? any vac line?

what should i be reading? 15-20? i know it is measured in (inHG)

[VileZambonie]

How are you setting your timing

Hook the vacuum gauge to an intake vacuum port and route the gauge up to the windshield. Duct tape it to the windshield and put the truck in gear. Accelerate to WOT and observe the vacuum gauge. It should drop to zero and rise. If it stays at zero suspect a plugged exhaust.

[spectreblazer]

How are you setting your timing

Hook the vacuum gauge to an intake vacuum port and route the gauge up to the windshield. Duct tape it to the windshield and put the truck in gear. Accelerate to WOT and observe the vacuum gauge. It should drop to zero and rise. If it stays at zero suspect a plugged exhaust.

i set #1 cylinder to TD

then i used a timing light. i took it into my automotive class once and a mechanic i work with helped me the other time.

[zieg85]

How are you setting your timing

Hook the vacuum gauge to an intake vacuum port and route the gauge up to the windshield. Duct tape it to the windshield and put the truck in gear. Accelerate to WOT and observe the vacuum gauge. It should drop to zero and rise. If it stays at zero suspect a plugged exhaust.

Awesome bit of knowledge to lock up in the vault... Hope I can recall it when I need it.  Thanks Vile..