Thread: need help with truck

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i'm new to hot rodding, built a truck that nobody in this area seems to be able to help me tune. what i have is an 85 c-10, with a 350 cid bored .030 o.s., decked .025", .030" domed pistons, 244/254 duration .510/.533" lift cam, weiand tunnel ram and holley 450 cfm carbs. i have it timed 23 degrees advanced. it seems like no matter what i do to the carbs, it acts and smells rich. i was wondering if any of you have run a set-up similar to this, and if so would you tell me what you did to the carbs to make it run half a** right. thanks

Tunnel rams are designed to run high rpm's, usually work best from 4000 to 8000 rpm. On the street at low rpm's they tend to run rich, sometimes playing with jet sizes and power valves will help. Are the carbs vacuum secondaries or mechanical???

they're mechanical. how do i go about figuring which power valve i need? would i check vacuum at the carb, or on the back of the manifold? with the truck in drive or park?

hmmm. I suppose an automatic trans, too???

sounds like your setup isn't really made for street but more for drag racing.... you need more advance out of that distributor, a hotter ignition, and a lot less fuel...

What cc heads are you running? Which dist.? Have you curved it in yet? Are you running a fuel reg.? Did you degree in that cam?
Need more info plz.

automatic trans, i built this motor over 9 years ago, its been sitting on an engine stand ever since, put it in the truck and it fired right up, i was 13/14 years old when i built it. so i don't remember everything that was in it. first motor i ever built. heads cc i don't know, mallory uni-lite dist. i have set at 23 degrees adv., fuel reg. is set at 6 psi., no i didn't degree the cam.

Do you have a dyno service near you? This will be the best way to go from here...takes out all the guess work.

no, nearest town with anything is houston and that 2 hours away

Well then- remove the valve cover and look between the rockers to find the head numbers- get them so we can look them up. Do you remember if you had the heads worked for flow?

the heads are 882? 883? they're 88something no, just new valves, new guides ported and polished exhaust, but we left the intake ports alone.

My guess would be too much carb and not enough runners in the head. Vacuum secondary carbs would help, at least it would lend more adjustability to the setup.

It would seem the engine could handle a bit more total advance, how much do you have in intial advance, and at what RPM is all the advance in? IMO the engine should hand 32 to 34 degrees total advance. Hopefully the chebbie guys will be along with all the exact numbers.....

I run around 32* advanced on my stroker, with a 670 cfm Holley.
Any bigger a carb and it floods ( on the street ) .
You might have to drop down on jet size's, or order up a set of 380 carbs.
I HATE 882 heads, I have tried running them and I didn't like them - swaped them out and cured a lot of my troubles, but a lot of people like them so I guess it's just a preferance.
Try to get it on the dyno- that will tell the tale of all your woes.

I work on a LOT of F#*ds Dave- but all I drive are Chevy's.

o.k. i got the truck to idle, did a vacuum check on it in gear. the truck idle for about 15 seconds, long enough to get a reading. the vacuum gauge read 4 inches. so i ordered some 2.5 power valves.

the stock power valves in the carbs are 6.5 which means when i put the truck in gear, it opens richening the mixture and eventually killing the motor.

as soon as i get the valves and install them, i'll recheck the vacuum and keep you guys posted.