Thread: Should I keep my stock Carb?

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Hi,
I am a new member and should spend a lot of time searching for my answers before posting such a basic question. I am sure you guys have answered these questions before but I have already taken tools to the job.

My truck is an all original '72 C20 4-barrel 350 with 125K miles. Have owned it for 16 years. Love it! Last year I broke a timing chain in the middle of the OR mountains and had to have it repaired by a local Chev dealer. Since the valves dinged the pistons a few push rods got bent. I had the chain replaced and I limped home. I took the heads off and did a valve job and replaced the bent push rods. The pistons hits were minimal. Put it back together and put 2500 mi on it. Since this started it has run rough--esp at idle. As it turns out the mechanic didn't put new gaskets when he did the timing chain and that is the source of the oil leak. Since I have it torn down, I bought a new mild cam to stick in while I have it apart. I am also going to replace all the push rods. My theory is that the banging on the valve train hurt a lifter causing the miss. But the cost of the cam with new lifters was so small it is worth the effort.


So the question. I was thinking of puting one of the Edelbrok performer carb and manifold but some local guys said it was a wast of money since the GM+QJ is a very good combination. What do you guys think? I am not that interested in performace but am in reliabilty, fuel milage and smoothness. The only other mod that I am planning is a 700R4 upgrade because the cheapo replacement TH350 I put in has a vibrating TC.

Sorry for the long winded post but I need to get the beast back on the road. Thanks for your opinions.

john.

This is probably not what you want to hear, but with 125k on the clock and the problems you encountered I believe it's time for a complete engine rebuild.
Othewise, in my opinion, you'll have more problems further down the road. At the present time if the engine isn't burning oil , it soon will.

hello. if it's reliability that you want then you are probably best to stay with the q-jet. they are as reliable as you can get ,but on the other hand you could change it out to the eld'y and it's also a good carb. it all depends on what you want for the truck.you may want to check your valve springs as you do the job at hand.. and i also agree that you may be in to a overhaul with that milage. if you go for the change of the carb then stay around 600 cfm on the carb. good luck and wecome

Both of the guys who posted above me were reading my mind. There have been engines like yours go to many more miles, but you have already experienced some problems that signal it is not going to happen for yours, most probably.

Another factor is TIME, this truck engine is now 34 years old, and things dry out and age in that time. I have to school my customers at my marina all the time on this fact. They bring in a 5 year old boat and say "but it only has 50 hours on it." and I have to tell them, "yes, but it is 5 years old, that is what counts." I drive an '84 Ford that just turned 60,000 miles, but things are aging on it, and you can't equate it to a two year old car that has 60,000 miles on it.

Buy a Goodwrench replacement engine, forget the cam swap, and maybe rebuild the quadrajet. You will get a Goodwrench for the same or less than you will spend rebuilding your engine, and get a 3 year warranty.

Just my 2 cents worth.

Don


PS: Welcome to the forum.

I agree with Don, best value for money spent.

Thanks all, good guidance. Since I a retired and have more time than money (or brains) and I have the cam, I am going to put the cam it, slam it back together to drive while I shop for a crate engine. There is a place in OR that sells them for a good price (Salee I think). This way I can use it to tool around for a while. I have been promising myself that I was going to paint it back to original.

OBTW, I have been reading posts about adjusting the valves and I had the thought about how you get oil into virgin lifters to ensure that they adjust correctly? Or is just the fact that you take it one turn after contact and the internal spring keeps everything going until it pumps-up?

Anyway, great board--great info. Glad I found it.

john,

1970 Jeepster (real fun)
1972 C20 (old friend)
1996 Saab (Just comfy for long rides)
1998 Jamboree (Escape Capsule)

My opinion is that at qjet is one of the best carbs ever made. Yours has lasted since 1972, that says something. While the edelbrock is also an excellent choice, I still think you will be happy with a properly rebuilt and tuned qjet. ( I even put one on my mopar, the purists would cringe.)

I have never had any trouble with lifter bleed down on a stock SBC if after adjusting them (before cranking the engine)
Good luck.

my dad put the 260 HP Goodwrench in his '72 C10, runs great. original engine quit 2 cyls and the original engine was leaking at the rear main. now we'v got a buildable 350 to play around with

Don't worry about having oil in the lifters at start-up. That malarky about soaking them overnight is just that....Malarky.

Richard,
Thanks for the info.

After pulling the lifters out, a couple of them showed little black specks that I assume points to the cam being bad as I suspected. That makes me think that I should get a short block. I just put $500.00 in the heads so either I do the bottom end myself or get a short block. I now believe (agree) with you guys--it is time to take care of the bottom!
john.

hi. you said that you were going to adjust the valves to 1 turn on the sbc, i think that you should adjust them only 1\2 turn and it will run better that way , 1turn isn't needed on that engine. i have always only gone 1\2 turn and it's easier on the cam also. good luck dave

create are nice but that is all you are getting since you can and are able to do the rebuild this is what i did and beleive it turn out to be a sweet motor 350ci bore 30--now you have 355 ci fit with 10-1 flat top piston new rods install a low towing cam and throw away that q-jet as you add eldbro,carb and manifold i been building small blocks for several years and i have never saw a good q-jet but a lot of people like them--my motor was in a 83 pickup 4 wheel drive and belive it is a joy to drive on anf off road you will not be dissatifed
sam

create motor are nice but that is all you get--since your able to do the work yhis is what i did--350ci bored 30-now it is a 355 ci--fit 10 to1 flat top piston and a good set of forged rods new rings,bearings and pins--add a low towing cam and a good eldbr.-carb and manifold and good set a headers and 3in dual believe me i did this to my 83-4wheel drive and it was a fun veh-to drive on aa off work

Hi,
I'm back... After a few days of looking things over. A check of the rear main showed evidence of leakage. I decided to pull the motor for a good inspection. You guys were right about reduing the bottom end. The first thing I found was residue of the timing chain in the pan and oil pump screen. I pulled a main cap and saw evidence of foreign material. So minimum is Crank and if I go that far, I might as well do the whole thing.

siw234:
Could you provide more information on your rebuild? How much work did you have done on your block? Linebore, etc.

Thanks guys.

Even once you redo your lower end, I would still stick with the Q
'jet.........It is a good reliable carb. I would rebuild it though.