How to spend $1500 on engine upgrades

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JasperStam

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I have a 77 C20 with a regular 350 V8 that is pretty much as stock as they come. I have had it for 8 years now, but I dont know if it ran the stated 86.000 Miles or maybe a 100k more. Motor runs pretty smooth though a little oil may leak. It has a standard 2 barrel carb. Pretty sure nothing has been done to it all its Life. Anyway, I have about 1500 to 2000 in parts and labour to spend on the engine. Some maintenance and upgrades. I am not much of a road racer but it can use some extra kick getting off the line. Any tips on where to start and in what order.?
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1987 GMC Jimmy

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Mild cam, rebuilt Quadrajet, some better heads or have those worked (depends on the casting no.), long tube headers or ram horn manifolds, aluminum intake (mostly for looks and ease of assembly), and removal of emissions junk are the classic upgrades. What are the emissions requirements over there? You can probably check the Carfax and see what mileage it had on it at different points during its life in the States. Unless it was an export model or someone took it over there early on. If it had 86,000 miles in 1986, chances are that the odometer has turned over at least once before. Gear ratio is important, too. I'm sure it's fair to assume that parts and service are difficult to come by. For instance, if you wanted someone to do your cylinder heads, it would be hard to find someone if anyone could do it at all?
 

fussfeld

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This is just my opinion, but:

1) Compression and leakdown test.

2) If everything checks out, then a good set of headers and dual exhaust and that's it.

Also, as blue said, what is your rear gear ratio?
 

Camar068

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as they've said above gearing or engine. Gearing would be higher on my list if you have good size hills or mountains in your area and you have 3.08's. If you have 3.08's in a flat area, I wouldn't worry about it too much.

But I would start with the simple/cheaper stuff first.

-inspect/replace as needed cap/rotor/plugs/wires
-fuel filter
-have carb rebuilt ($50 -$100)
-sea foam engine oil and fuel (plenty of video's online)
-spray vacuum hoses/carb/intake for leaks with starter fluid (fix the areas you find that change the idle)
-fix any exhaust leaks

Just a few, then go from there.
 

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I agree. Starting simple can make more difference than some people think.
 

HotRodPC

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I am going to go with the gear ratio is fine. Very common in round eye years, that C20's got 3.73 or 4.10's so he'd be good there if that's what he got. Being a small block it's probably got a Th350 if it's not a manual and that's fine too. Th400's were in the 80's small and big block C20's, but Th350 is fine for a C20 small block truck, in fact it would be my preference.

Are you doing the work yourself? This is important to know so what can be done with your budget if it's your labor or are you paying for labor? I almost hate to see you do much more do it since it's so unmolested. I like that it's all OEM still down to the air cleaner and heat riser pipe on the factory exhaust manifolds. Don't even lose that ****. Even if you choose to go aftermarket intake, carb, headers and such, save that stuff or ship it my way.
 

JasperStam

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Thanks for all your answers. Great to have so many thinking along. The car was imported here in 2010. Apparently served as a company car for a painting firm in L.A. Once sold by Schonlaw in Hollywood. Still has Some painting stains on it. Original AM radio in it when I got it.
Dont know the gear ratio, but i’m pretty happy with it. 3 speed automatic. Allready got rid of the exhaust recirculation crap. There is no emmision testing on old cars here. I am kind of anxious to keep it looking original as much as possuble. Not a big fan of Chrome. We can get pretty much anything here part-wise, it just tends to be 40% more expensive. Cilinder heads are a bit tricky to come by. A friend is a mechanic who can work on it weekends.
I think I’ll go with a four barrel carb and a mild cam upgrade plus dual exhaust since that wont change the original looks much. Any idea on those parts, especialy the carb? Are the ram Horns worth it? Is there an intake that sort of looks original.? What about electronic ignition , does that do really anything for performance or mileage? Thanks again for your replies.
 

JasperStam

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PS already did the spark plugs, oil filter, checked for leaks. Oil is clean. And the country live in is as flat as they come!
 

fussfeld

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1) Can you take a picture of the rear diff and/or the rear wheels?

2) Now that i re-read your first post and realize you have a 2bbl, then i might also suggest an Edlebrock performer RPM intake and a quadrajet in addition to my previous suggestion of a good set of headers and dual exhaust. But that would be it.

Because the engine is a 77, i would want to do a compression and leakdown test on all cylinders before doing anything else.....
 
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shiftpro

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What nobody is recommending a roller cam?
 

yevgenievich

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Late 70's had some of the worst compression and light casting heads. If you open it up and doing work, verify it is still healthy and change the hole top end on it.
 

Rusty Nail

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Hallo!

WoW that original beauty is GORGEOUS, i'm with you...I dig that classic look too.

A 1977 engine already has electronic ignition- GM's HEI was introduced in 1974.

$1500 is a tight budget start to finish for a total package, this thread will be interesting! And fun!

Converting to "roller valvetrain" :rolleyes: is cost prohibited and a ridiculous notion...I apologize for them. :confused:

A four barrel carburetor will seem like a HUGE power improvement I think although results may be mixed.
You will likely add a few ponies but at a great long-term cost that demands consideration.
Gas mileage WILL suffer drastically so be prepared for that and be sure to closely guard that 2 bbl carb. You may want it one day!
That said, I believe that a four barrel carb is the primary most logical choice for "improved" performance on your budget.

GM made some very good aluminum intake manifolds for Quadrajets.
#3932472 for example..lol.
I would seek out a factory aluminum intake and get some "corporate blue" paint to run a Quadrajet with. You WILL like the improved power AND response = paint it up and it will be awesome!

I think if you bought COMP CAMS 1.52 ratio "Magnum Roller Tip" rocker arms, they can yield a very decent "bang for the buck". You safely and without further modification, increase rocker arm ratio / cylinder head flow AND enjoy the benefit of being ensured that all valves see uniform lift. This is VERY underrated albeit VERY important.:cool:
Re-paint the valve covers, nobody is the wiser and it'll look great plus rev further and more freely.
Win/win!
You could / I probably would / repaint and "rebuild" the factory air cleaner and install a K&N air filter. I think it's 11x8 or something close and "semi gloss" black paint. Verifying proper function of the E.F.E / HEAT RISER is essential.
Up to this point, you really haven't spent much money in the big picture...but speaking of that big picture, exhaust is the other side of intake flow and that must be addressed also. It doesn't have to be flashy or loud, but there are many ways to improve function without detracting from your goal.
I believe two pipes is quintessential. I also believe they should be connected as close to the engine as (reasonably) possible. Tailpipes are a must or you kill exhaust velocity and it WILL drone. You can spend as much doing the "back side" as we have up front.
For your power levels I think 2 inch pipe or 2.25 is desired. Are the ram's horn manifolds worth it?
I have zero experience to speak from regarding but do not believe their reputation is fiction.

Soooo, let's assume we've spent HALF of your budget assuming custom bent exhaust at a shop.
Aluminized pipe or GTFO.
:D
One muffler or two?

We must also assume that $2,000 REALLY IS the high side of the budget and if we're lucky, you still have $1,000 left.

What are you going to spend it on? I am not that optimistic lol. I believe we are closer to $12 or 1300 improving the intake and exhaust and consider $750 left tops.

Do you think that is enough to "rebuild" your cylinder heads and put it back together? Hope for #882s.

P.S. lookit @Charlie <40 minutes..

:welcome:

*edit*

"How to spend $1500 on engine"
I think we're pretty close in Amsterdam. On second thought - in addition - I would also buy a new HEI distributor, ($50-100) MSD StreetFire wires (they're black), new AC Delco R45TS plugs, change the oil/filter/PCV valve, fix/re-route the vacuum lines and enjoy it... Pop the hood and show it off!
That's $1500 I bet.

YeeHawww!

Maybe think about the heads for later...that's where the real power is. ;)
 
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