Car Advice Please

[zcubed]

I have a 1978 Chevy Blazer 4X4 with a stock 400 small block. It has approx. 90,000 miles on it. It's been in the family for quite some time and has been sitting out in some woods for about the last 5 years. I've retrieved it, and i am trying to get it up and running again. I already spent a grand on it just getting it operational. It is now running fairly well, but it still hesitates at times when i take off from a stop light, and it bogs down temporarily when i punch it at about 40 or 50 mph. I don't know much about it, but i'm thinking it may be a carbeurator problem? Does this sound right? If so, is it generally better to buy a new carb, or is rebuildinig a carb a good option? Like i say, i've already spent a grand and i am not wanting to start funneling a bunch of cash into this thing. I've been looking through all those magazines, and they're always advertising 600cfm -- 800cfm carbs. Is one better than the other? Maybe the truck is so old that i am at peak performance now (without a major overhaul)?

One thing i am getting ready to do is put in a new exhaust system. I was thinking about headers, but the guy at the exhaust place said that headers are a headache. He said that they require constant maintenance to ensure that the gaskets are tightly sealed. Is this correct? He also said that headers wouldn't do me much good unless i also modified the engine (i.e. new cam, etc.) What do ya'll think. The magazines seem to be strongly pro-header, but i cant tell if they really mean it, or if they are just trying to push their advertisers' products. Any input is most appreciated. Thank you.

[2gapa]

A '78 engine with 90K on it is probably ready for a major anyway. You might want to see if you could get by with a rebuild or a junkyard carb.

[RATTLESNAKE]

Advance your timing,your timing chain is probably a little stretched with all those miles.also,go to the next highest level of octane next time you fill up. The Snake Do these two things before spending cash you don't have to. Remember,process of elimination,start with the cheapest fix first..I think you'll find that i'm correct.

[ac4zu]

You might as well keep it because nobody is going to give you squat for it. You have a good vehicle that can be reconditioned from bumper to bumper for a reasonable price. Parts for this vehicle will be cheap and plentiful. I have a 86 1 ton Chev dual wheel w/ a 454 that has 160K on it and it's still going strong with the original engine (does not consume oil & has plenty of horse power). I don't really need it, but nobody will give me anything for it so I might as well keep it. We've had it since it was new and is still a good truck. The 400 you have is an excellent engine. Peak performance? Does your 400 burn any oil? If not, it is probably OK. If it does burn a little oil try running some risoline oil in it (great stuff), might fix it-might not.I have had carb trouble with mine. Have you changed your fuel filter? My original carb has now been gone through three times; it is now worn out and needs replacing. It has a Rochester Quadra jet on it, which is an excellent carb, but is very expensive to replace. I'm sure yours has a factory Quadra jet on yours as well. If it has never been rebuilt before it is probably best that you have that one overhauled by an experienced carb rebuilder. Your float might need replacing. Good luck on finding a good rebuilder! The old experienced rebuilders are getting hard to find. I would stay away from a Holley unless you like adjusting carburetors all the time. Holley's are great carbs, but they need a lot of attention. If you would like to replace it you can put a new edelbrock carb along with a new matching edelbrock high-rise manifold for the cost of a new Quadra jet. It is a solid setup; we have one on an el Camino that we put a 350 in. The Holley or quad would yield better performance, but the brand new, conservatly priced edelbrock combination works good and gives no trouble what so ever and it is also very easy to install and setup yourself. If you go this route, don't forget to get a new air breather for it. edelbrock sells a nice matching chrome unit.
I would not invest in headers unless you have a problem with your existing manifold. The magazines are assuming everyone wants a street rod. The headers will help a little with out the engine mod, but would it justify the costs and maintence down the road? In our case no, we just want a good running ride. A new setup from the manifold back would be good since yours is probably rusted out. Make sure you use a good muffler shop. I have been a victim of a cheap muffler shop with my 86. They like to weld and their welds are done too quickly and are not solid and leak rather quickly resulting in premature rust out.
I have had consistent radiator trouble with it. The 454 likes to run hot by nature. After three cheap auto parts store special radiators I finally slipped a GM aluminum replacement in it and have had no trouble since. Your 400 will probablly not have that problem.
Oh, I used to foul plugs on a regualar basis, but switched to Bosch platnium plus many moons ago and found these plugs to be indestructable (they last forever).

[RATTLESNAKE]

SHeeeit,rebuilding a carb is childs play...just get the rebuild kit,look at the parts,and switch them out,then make your adjustments...piece of cake..The Snake

[zcubed]

Thanks for all the replies, guys. I really appreciate it. I did replace the fuel filter -- i couldn't go over 30 mph before then. The exhaust system is rusted out. I was thinking of taking it to Midas to do the exhaust work. The rig is not burning oil, and the radiator is doing its job. I have been looking at the edelbrock package (hi-rise man. and carb.) in the magazines. I may see what's available at the junk yard -- i just hate to replace a bad carb with a bad carb though. I have put a 9 in. K&N filter in a chrome cover on. I think i will look more closely into the edelbrock set-up as i can't seem to find a mechanic/carb rebuilder i am completely comfortable with. (I think i got taken on the original mechanic work). Thanks again, guys.

[noshoes]

AHH the old days, Ive build a few cars in my days, I doubt if its a float problem, truck wouldn't start, either flood out or starve for gas, First thing I would change, (now let me remember) I do believe there is a excelerator pump in the carb, I think thats what they called it, Its been awhile since ive torn one down, Im sure some one will let me know if i'm mistaken, Anyways, Ive got a 69 vette, with a 350 LT1,(370 HRSE stock) 400 turbo W/A 3500 stall, and some other goodies, I built it in 80/81 Won a few trophy'S
when i use to show it in World of Wheels, Anyways, Going to get rid of it, and maybe build something else, Trying to get this 37 dodge with suicide doors thats in the family, Its been dormant for 34 years, That will be a project.

Oh yea, Headers are nice if you get a good set, were they seat nice to the manifold, they won't loosen up and have to be retorqued as often, and a nice set of flow masters.

[Betsy]

Noshoes is sopt on! From sittig up for a while the carb pump is most likely gummed and does not move as it should. That is the reason for the hesitation when depressing the pedal.
It is an easy job to take the top off of the carb and free up the thing. Leave the headers alone unless you intend to run wide open in ALL gears. The stock pipes do the job well at all normal speeds.
Betsy

[RiseStar]

Hi Betsy,

Long time to see. :)

[Digital_Insight]

I agree with Betsy. I think it's the accelerator pump. Also may be running a little rich overall.

[sparker]

is it doing this when it is hot or cold check that the choke pull off is working the thing with the vac hose going to it when the truck starts you will see the plunger pull on the choke rod and helps hold the choke open

[quaddawg]

In addition to the accelerator pump itself, make sure all the fuel and air passages are clear too, as well as the jets. The little valve attached to the float gums up too.

Basically, after sitting that long, all the old gas turns to gunk, and it will clog up everything. Every tiny little passage. Rebuild the carb, (kits are around $20) And soak the carcass in carb cleaner (remove any plastic) then blow all the passages out with compressed air, or better yet, take it and have it dipped. (local garage maybe)

I have rebuilt a BUNCH of bike carbs, bikes tend to get stored incorrectly alot. I have seen carbs so bad that nothing would clean them. I am not too familiar with your quadrajet, (that was my pops specialty) but the same rules apply, everywhere gas stood for awhile, there is now GUNK.

[zcubed]

Thanks again, everyone, for all the replies. This definitely gives me something to go on. I will check the accelerator pump, timing chain, choke, all of it. I think i will also give the rebuild kit a try. If i screw it up, then i guess i could always go with the new edelbrock, but it's worth the risk, because i will certainly learn something in the process -- and with such an old ride it would probably be good for me to learn how to maintain it myself, instead of taking it in for everything ($$$). Thanks again.