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305 Rebuild/Upgrade

  
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305 Rebuild/Upgrade

 
mrbigA47 mrbigA47
I love my Chevy Chevette! | Posts: 10 | Joined: 12/12
Posted: 01/15/13
11:25 PM

I have decided to upgrade the stock 305 in my 86 El Camino instead of replacing it with a 350. My budget is $2000; what performance upgrades can I make during the rebuild to produce HP gains ranging from 220 -250?  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 01/16/13
04:03 AM

MrbigA47

  You have the LOW HP of the 305.That will not be hard to do. Its all induction with the little 305.
  I have an 86 Monte Carlo SS, and all I ever did was install a home made trans. shift kit. Then installed the biggest transmission oil cooler I could get under it.... We are the only owners we got it Christmas EVE 1985. It was a Christmas Present for my wife. I can melt the tires if I wanted too.... I believe it still has the same belts on it. It has 55,000 miles on it.  With that said.

1.Are you rebuilding the engine? Is the engine coming out of the EL.?

2.If not you need to do at least a cranking compression test, and/or leak down test to find out what the rings are doing. You didn't mention how many miles are on it....

3.If you can find these heads P/N 14022601 they are the 180 HIPO 305 heads. the valve size is 1.84"/1.5" they have 58cc chambers.
NOTE: You could mill your heads to 58cc, but you will need to mill the intake manifold also.

3.A.NOTE: DONT USE A SMALL BLOCK HEAD WITH AN INTAKE VALVE SIZE BIGGER THEN 1.84" THEY WILL NOT FLOW DO TO SHROUDING.Don't let the machine shop or anyone else talk you into it...

4.Cam you will need. General Motors P/N14088843 .202/.206 duration at .050 .403/.415 max lift with 1.5 rocker arm.....

5.I found 3 cams for the 305. I will list them as I would choose them.If I were doing your 305 over. They are all Comp Cams.

6.Comp Cam P/N 12-670-4 Grind #N+300HP
Good power and throttle response. Nostalgia flat tappet.
1000-5500 RPM Power Range
.211/.218 duration @.050  .426/.420 max lift with 1.5 rocker arm ratio.
112* Lobe seperation 108* intake valve center/line.

7.Comp Cam P/N 12-388-4 Grind 252AH-12
1000-5000 RPM Power Range
.206/.212 duration @.050  .425/.440 max lift with a 1.5 rocker arm ratio.
112* Lobe Seperation 108* intake valve center/line

8.Comp Cams P/N 12-305-2 (49) Grind P/N246PE
1200-5200 RPM Power Range
.203/.212 duration @.050  .429/.438 max lift with a 1.5 roacker arm ratio.
110* Lobe Seperation 106* intake valve center/line

9.The valve springs for these cams are all P/N 981-16
Valve locks are all the same P/N 601-16X2=32
Valve seals are all the same P/N 501-16
Cam break-in Lube P/N 159.

10.If you have your heads done you can have the valve springs replaced with the optional Z-28 valve spring. For any Cam....The machinist should replace all the locks and seals anyway. I suggest the umbrella valve seal.

Just a note. Not knowing what rear gear your EL has that will make a difference in the way the cams perform. I don't care if you put in the smallest cam I listed... You need at least a 3:42 rear gear and a 26" tall tire.

NOTE; The Monte Carlos either had 3:42 or 3:73 rear gears thats it. Thats what made them snappy!!! So if your EL has a 2:86 rear gear or different gear the performance will be there it will just take a little longer for the engine to respond, or get into its power band. All the cams come in early so it should be okay!. Thats all. Any questions please ask...

Bob  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 01/16/13
04:21 AM

I checked Jegs and Summit for the Cloyes timing chain set and their the same price.

Jegs P/N 220-9-3100 $89.99

Summitracing P/N CLO-9-3100 $89.99

Bob  

68scott385 68scott385
I have an SS396 tatoo | Posts: 325 | Joined: 07/09
Posted: 01/16/13
09:40 AM

Just the replacemnet parts, i.e. rings, bearings, gasket set, cleaning, plugs, wires, and cap & rotor will eat 1/4 of your budget. If your block needs to be bored, meaning it also needs new pistons, you're looking at $300 for pistons and $8-$12 a hole to bore.

I suggest finding out what you have to start with first, then spend wisely on the induction side...cam & intake. Headers would be a good addition too but they can wait until after the motor is built and you can save some more money.

I like Bob's #7 cam.  
68scott385 68scott385 68scott385

mrbigA47 mrbigA47
I love my Chevy Chevette! | Posts: 10 | Joined: 12/12
Posted: 01/16/13
09:45 PM

Bob,

I thought I wanted 350+ HP, but that's not for me. I would be content to spin the tires from a cold or running start, daily drivability and a nice rumble from the dual exhaust. 3.42 gears are what I am looking for; although I was told that 3.73 would be better and I could get the same drivability using either the 200-R4 or 700 R4 transmission. I just needed to know specifically what mods to conduct on my 305 to make it hum. My $2000 grand budget will cover this calendar year. So I have to spend it wisely. I am not completely sure about all of the specs you have listed, but I will conduct the research and get back to you when I make my first purchase.

Ernest  

mrbigA47 mrbigA47
I love my Chevy Chevette! | Posts: 10 | Joined: 12/12
Posted: 01/16/13
10:07 PM

Thank you all for the quick response. My engine does not leak oil, but coolant is finding its way into the heads. I will assume that the engine has over a 100K, but after changing the fuel filter, spark plugs and redirecting a few tubes, I was able to get all 8 cylinders working. my very first purchase will be the GM service manual for that year ($150). The next step will be to identify and stop the leak. Third, I have to replace the thin-colored vacuum tubes the previous owner opted for with REAL VACUUM tubes. Basically, once the 305 is running straight normally, I will attempt to locate a reasonably priced overdrive transmission and then replace the rear end gears and add posi-traction. The tires will be 16 or 18 x 8 with an overall diameter of 26". 220-250 HP throughout the normal cruising range (1900-2200 rpm) is all I am looking for. That's what my truck has. This will be my toy.  

68scott385 68scott385
I have an SS396 tatoo | Posts: 325 | Joined: 07/09
Posted: 01/16/13
11:52 PM

Exactly what do you mean by coolant gets in the heads? Does the coolant spew out of the radiator when the thermostat opens?

Your 86 model should already have an overdrive transmission in it.

A performance rebuild will take all of your budget. A basic rebuild will take at least half of your budget.

A new posi unit, set of gears, and install kit will take half of your budget.

16" or 18" wheel with 26" tire? VERY short side walls >> easy to ruin expensive wheels on imperfect road surfaces.

You could probably find a GM service manual on eBay for 1/2 or less than the price you quoted.  
68scott385 68scott385 68scott385

68scott385 68scott385
I have an SS396 tatoo | Posts: 325 | Joined: 07/09
Posted: 01/17/13
12:20 AM

Is this what you're looking for?

http://www.ebay.com/itm/1986-CHEVROLET-CAPRICE-MONTE-CARLO-EL-CAMINO-SERVICE-MANUAL-ST384-86-/350656934303?pt=Motors_Manuals_Literature&hash=item51a4c8319f&vxp=mtr

http://www.ebay.com/itm/1986-Caprice-Monte-Carlo-El-Camino-Service-Manual-Chevrolet-Chevy-OEM-ST-384-86-/200880422895?pt=Motors_Manuals_Literature&hash=item2ec567ffef&vxp=mtr  
68scott385 68scott385 68scott385

mrbigA47 mrbigA47
I love my Chevy Chevette! | Posts: 10 | Joined: 12/12
Posted: 01/17/13
11:15 PM

Yes it is and thank you for the link. Chevrolet wanted $200.  

mrbigA47 mrbigA47
I love my Chevy Chevette! | Posts: 10 | Joined: 12/12
Posted: 01/17/13
11:36 PM

I get white smoke when I initially start my car, especially if it has sat a few days. Then there is a burning smell that follows after the car has ran awhile. Keep in mind there is no oil in my garage or on the manifold and the car has been in my garage since December 15th. Autozone mechanics and the guy that looked at it when I bought it attest that black smoke is an oil leak while white smoke is coolant. If you haven't already guessed, I am new to the troubleshooting phase of cars. Once the problem is identified, I can usually work it out. Most of my knowledge comes from reading and advice from individuals such as yourself. The advice is sometimes conflicting though.

No my car does not have an overdrive transmission. It's the stock three speed.

16's still offer a beefy tire. 18s were the max I would go for looks.

Getting my 305 back stock at this time will suffice so that I can park my truck. The transmission and gear set should give it new life until I get bored. There is also plenty of stuff I need to address throughout the car, hence my need for the GM manual, before it is ready for even a MAACO paint job. It is truly a project car.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 01/18/13
02:35 AM

Ernest:

1.That oil puff of smoke is common to SBC. The exhaust valve seals dry up, and oil runs down the valve stem. Then when you start the engine the puff of smoke. You will never see it outside the head or on the ground, its internal.
2.The guys at Auto Aone think its coolant? Ernest, here is what you need to do.
2.A.Remove the heavy RED wire from your distributor cap. That will disarm your ignition.
2.B.Now remove all the Spark Plugs. Leave them in their respective order on a piece of heavy cardboard. Number them Left Bank 1,3,5,7. Right Bank 2,4,6,8.
2.C. Remove the radiator cap and fill the cooling system.
2.D. Install Cooling system pressure tester, pump the cooling system to the raditaor cap pressure. You may have to do this a couple times as the engine coolant temp drops the pressure will drop. I suggest doing this test when the engine is at ambient temperature.
2.E. After the pressure has stablized, (if not there is probably an internal coolant leak). Have a friend crank the engine, while you watch to see if any coolant blows out of the cylinders.

  NOTE reinstall the spark plugs, and the heavy red wire from your distributor cap.

Ernest follow the above procedure to check the cooling system for an internal leak.

I would be more concerned about an internal coolant leak then You should be about a puff of oil. When your heads are rebuilt new valve seals will be installed. As I mentioned the oil puff is common to SBC. My Monte Carlo has never be apart and it puffs even if it sits 8 hours.
  I also left you a PM. Good Luck

Bob  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 01/18/13
02:36 AM

Icon QuotemrbigA47:
Bob,

I thought I wanted 350+ HP, but that's not for me. I would be content to spin the tires from a cold or running start, daily drivability and a nice rumble from the dual exhaust. 3.42 gears are what I am looking for; although I was told that 3.73 would be better and I could get the same drivability using either the 200-R4 or 700 R4 transmission. I just needed to know specifically what mods to conduct on my 305 to make it hum. My $2000 grand budget will cover this calendar year. So I have to spend it wisely. I am not completely sure about all of the specs you have listed, but I will conduct the research and get back to you when I make my first purchase.

Ernest


You bet Ernest I'll help you in any way I can...I have left you a PM.

Bob