Dual overhead cam, 16 valves, cast aluminum block and head, 3.5" x 3.16" bore and stroke, 8.5:1 compression ratio (1975), 8:1 compression ratio (1976), five main bearings, solid lifters, electronic fuel injection. 120 hp @ 5200 RPM, torque unknown (1975) 110 hp @ 5600 RPM, 107 ft*lb @ 4800 RPM (1976)
Duke (doctorduke), who knows more about Cosworths than any general-purpose specs book, clarifies:
"Early press reports talked of 140 net HP, and the ill-fated '74 configuration was rated at 130 SAE net at 7000. Early '75 press info mentioned 111 HP, but the official final specs were (SAE net) 110HP @ 5600 and 107 lb-ft @4800. The compression ratio was listed at 8.5:1, but running the numbers from the clearance volumes listed in the FIA homologation papers yields about 8.2:1. Despite what appears to be a more restrictive exhaust in '76 all the ratings and specifications from '75 carried over to the '76 model year."
Single overhead cam, 8 valves, aluminum block, iron head, five main bearings, hydraulic lifters (1976-1977), 3.501" x 3.625" bore and stroke, 8:1 compression ratio, Rochester 1MV 1bbl carburetor. 90 hp @ 4600 RPM, 136 ft*lb @ 2400 RPM (1971, pre-SAE net HP std) 80 hp @ 4800 RPM, 121 ft*lb @ 2800 RPM (1972, pre-SAE net HP std) 75 hp @ 4400 RPM, 115 ft*lb @ 2400 RPM (1973-1974) 78 hp @ 4200 RPM, 120 ft*lb @ 2000 RPM (1975) 70 hp @ 4400 RPM, 107 ft*lb @ 2400 RPM (1976)
Same as above except with Holley 5210C 2bbl carburetor. 110 hp @ 4800 RPM, 138 ft*lb @ 3200 RPM (1971, pre-SAE net HP std) 90 hp @ 4800 RPM, 121 ft*lb @ 3200 RPM (1972, pre-SAE net HP std) 85 hp @ 4400 RPM, 122 ft*lb @ 2400 RPM (1973-1974, SAE net) 87 hp @ 4400 RPM, 122 ft*lb @ 2800 RPM (1975) 84 hp @ 4400 RPM, 113 ft*lb @ 3200 RPM (1976) 84 hp @ 4400 RPM, 117 ft*lb @ 2400 RPM (1977)
Overhead valves (8), iron block and head, 4.00" x 3.00" bore and stroke, 8.3:1 compression ratio (1978-1979), 8.2:1 compression ratio (1980), five main bearings, hydraulic lifters, Holley 5210C 2bbl carburetor (1978), Rochester 2SE two-stage 2bbl carburetor (1979-1980), crossflow head with aluminum intake (1979-1980). 85 hp @ 4400 RPM, 123 ft*lb @ 2800 RPM (1978) 90 hp @ 4000 RPM, 128 ft*lb @ 2400 RPM (1979) 86 hp @ 4000 RPM, 128 ft*lb @ 2400 RPM (1980)
90-degree, overhead valves (12), iron block and heads, 3.50" x 3.40" bore and stroke, 8.0:1 compression ratio, four main bearings, hydraulic lifters, Rochester 2GE 2bbl carburetor (1978), Rochester M2ME 2bbl carburetor (1979). 90 hp @ 3600 RPM, 165 ft*lb @ 2000 RPM (1978) 105 hp @ 4000 RPM, 160 ft*lb @ 2000 RPM (1979)
Same as above but with 3.80" x 3.40" bore and stroke. 110 hp @ 4000 RPM, 175 ft*lb @ 2000 RPM (1975) 105 hp @ 3400 RPM, 185 ft*lb @ 2000 RPM (1976-1978) 115 hp @ 3800 RPM, 190 ft*lb @ 2000 RPM (1979) 110 hp @ 3800 RPM, 190 ft*lb @ 2000 RPM (1980)
90-degree, overhead valve (16), iron block and heads, 3.67" x 3.10" bore and stroke, 8.5:1 compression ratio, five main bearings, hydraulic lifters, Rochester 2GC 2bbl carburetor. 110 hp @ 3600 RPM, 195 ft*lb @ 2000 RPM (1975-1976)
Same as 4.3l but with 3.74" x 3.48" bore and stroke and (in 1978-1979) 8.4:1 compression ratio. 140 hp @ 3800 RPM, 245 ft*lb @ 2000 RPM (1976-1977) 140 hp @ 3800 RPM, 245 ft*lb @ 2400 RPM (1978) 130 hp @ 3200 RPM, 245 ft*lb @ 2000 RPM (1979)
Same as 5.0l but with 4.00" x 3.48" bore and stroke. 125 hp @ 3600 RPM, 235 ft*lb @ 2000 RPM (1975)
Same as above but with 4bbl carburetor. Only installed in two Monzas in 1975 (one with C06 Astroroof!). HP and torque figures for the 1975 engine are unavailable, but the 1976 4bbl 350 makes 165 hp @ 3800 RPM, 260 ft*lb @ 2400 RPM; since HP on the 350 2bbl went up 20 from 1975-1976, a guess is that the 350 4bbl also gained HP in that range from 1975 to 1976, putting the 1975 350 4bbl in the 140-150 hp range. [this is only a guess; no official dyno results are readily available]
This list gives a basic idea of what came out each year. Unfortunately the H-bodies lived in a time when GM was trying to get emissions controls right, and created messy vacuum-line ridden contraptions to stick into its 1975-up cars. What's on your car may differ since some engines used different controls and California had its own set of controls.
The Cosworth Vega is a slightly special case. Its emissions sticker says "EFI-PAIR-OC EXHAUST" and also mentions a Vapor Canister.
Clyde (CJBIAGI) explains:
"I believe the first part is "electronic fuel injection," PAIR means pulse air injection (air pump going to the exhaust manifold), and OC Exhaust is the catalytic converter [OC = oxidizing converter; modern cars use TWC (three-way convertors)]. The vapor canister is just what it says, the vapor recovery system that connects to the fuel tank to capture any fumes. Usually this connects to the carb, don't know where it connects on a Cosworth though."
About the charcoal canister, Nick (nickster1_99) writes:
"It's not a major problem driveability wise if you don't have a charcoal canister hooked up to an engine. The tank will just vent into the atmosphere like older cars. DON'T hook up the tank vent to the manifold or pcv--all you will end up with is a bad running engine (vac. leak). Remember the canister was installed to reduce emissions. Everybody (me included) has disabled a emission device at one time or another. When you do this, you are removing some breathable air for your grandchildren."
Robert (twelve_second_vega) gives good details listed below. The basic idea is that you want your car to burn all of the gas it gets. This means that the air/fuel mixture must be precisely controlled. Computer-controlled cars use sensors and fuel injection to precisely meter the amount of fuel given to the engine. The H-bodies don't have this luxury, for better or worse. At least that limits the number of things you have to check.
In order of time/money required:
Robert (twelve_second_vega), a licensed California Smog Technician, writes: "When an engine is producing too much "CO's" it is ingesting too much fuel. High "HC's" indicate how the engine is burning the fuel. Common causes of high HC's are Engine Miss, Burnt Valve or a Vaccum Leak. If the valves are in good shape, compression is even and you have no vacuum leaks, you may retard the timing to effect a change in HC emissions. However, in California, you may only reduce the ignition timing 2 degrees either side of the manufacturers specifications. One other cause of high HC production is a faulty Catalytic Converter. Check exhaust pipe temperature in front of and behind the Cat. You should have several hundred degress higher temperature behind the Cat compared to your reading in front of the Cat. An example would be 350 degress in front and 600 degrees after the Cat."2.4 What are good ways to increase stock engine performance?
(check yourself for smog legality)
Kevin (SoloII_74) adds: "[The intake] could be duplicated without a whole lot of trouble, since it is just sheet metal. You should be able to go faster by increasing your compression (by milling the head & block, or custom pistons) to about 9-9.5:1 (something I can't do), changing the cam (I could not because of the rules), adding a used 4 bbl intake, or fabricating a dual weber intake, and getting a header from Ed (expensive, but worth it). With a little work, you should be able to make it to around 200 hp.
Unfortunately, the 4bbl intakes are hard to come by, and cams are getting rarer too. My '74 only weighs in at 2200 lbs. with me in the car, and your '77 wagon most likely weighs quite a bit more than that, so your 1/4 mile times would tend to be slower than that, unless you can get the weight down."
Tom (tbecker_525) says:
"The Crower cam I have is Part #07356, Grind No. 286-F, "COMPU-PRO".
I have the spec sheet.
Intake: Duration - 286 degrees, lift 477, clearance hot 022
Exhaust: Duration 294 degrees, lift 490, clearance hot 024
At .050" tappet lift - Intake opens 16 BTDC, closes 48ABDC; Exhaust opens 60 BBDC, closes 12 ATDC
Lobe seperation - 110 degrees
Duration at .050"
Intake 224 degrees, lift .477
Exhaust 253 degrees, lift .490
Best I can tell it's rather radical... I'm still looking to see the year of manufacture to determine whether it's hydraulic or not."
Randy (monzamiler) adds:
"Jeff, The last time I needed bigger valves for a Vega engine I got mine from Donovan Engineering in CA. They cost $35.00 ea. and were well worth the money. I ordered mine with cut down stems on the intake. Yes you can cut down a V-8 valve but you will need to use a lash cap. The only lash caps I found only left .002 side clearnce which I thought was a little to close to the lifter."
"My 140 we built for a 3/8 mile dirt track includes Buick V6 pistons, Ford smallblock valves, Lunati cam, Quarter Master 12lbs clutch, Isky valve springs, and some other little tricks. The combination yields a dynoed 150hp at 7,000rpm!. And they all told me it would never work. They're still scratching their heads."
About the clutch, he adds:
"The clutch is a 2-disk self contained assy. It is designed for a V8, but will bolt directly to the back of your crank. You run a flexplate in place of your flyweel. The assy is 7-1/4" dia. Its not much for taking off, but frees up big topend."
This engine is still popular in some oval track racing; that's one place to start.
See engine swap section 9B.1 for some hints.
Some suggestions (sort of in order of cost):
Robert (twelve_second_vega) recommends:
"Here is what I am using and it was not only easy to find, but easy to fit up. I used Fan, Clutch, Shroud and Radiator from a 1976 Pontiac Sunbird with a 231 V6. You drop the Vega Lower Radiator Mounts 3" and this Radiator fits right in. Use the Vega Upper Mounting Panel that has a "Lip" oin the top that serves as a sort of fan shroud on the 4 cylinder cars and attach the Sunbird Shroud to the Vega Upper Mounting Panel with a few well placed Pop-Rivets. That is all there was to it. Not a complete "Bolt On" but very close and the finished product looks factory."
Larry (vega_man_larry) adds:
"I once adapted a V6 monza shroud to a Vega. I had to trim the top of the rubber cushion where it attaches to the radiator because it isn't wide enough. I then screwed it into the top and used aluminum standoff spacers (fabricated from KS tubing from my ACE hardware store) that I screwed through to attach at the bottom of the shroud to the unibody. I'm presently looking for another V6 Monza shroud because the thing worked so good at slow speeds. I used a piece of foam between the rad support and the rad to cushion it to prevent chaffing damage. I used the round slotted stuff that comes stock on the Monzas. It's much better than the stock guard that came in the Vegas."
Aleck (stinkybuttihave) gives details about the generic Griffin radiator:
"I have the Griffin # 25241. This rad has the following specs:
These rads have the lower outlet angled up on the passenger side. You need to make some room on the bottom at each side for the tanks. The rad sits right on the lower part of the stock rad cradle. I have this rad and a long water pump and still have room for a good fan."2.6 What parts make up an alternator bracket for a V8 with no A/C?
GM parts 357037, 357036, 357003, 3570382.7 What cars have in-tank fuel pumps and what are good replacements?
All cars except those with the 2.5l Iron Duke have electric in-tank fuel pumps.
David (monzaaddict) says:
"Personally I think the pumps are junk If you are running a healthy v8 disconnect the pump and install a new tube through the top cover or a weld on sump. Then get a Holley blue pump and run either -8 braided hose or 1/2" aluminum tubing to the carb. I did not read your application so if you are just running a stock 4 cyl just try the repair I mentioned or go to gm and buy a new pump."
See 9.10 for fuel delivery ideas.2.8 What is one way to fix sagging motor mounts?
Nick (nickster1_99) suggests: "Here is a tip for all you with sagged out motor mounts. I bought some older style mounts for a 60s Chevrolet--the "pancake" style. I then took apart my sagged out oil soaked mounts. The part that bolts to the frame of the car was saved, the rest tossed. I then took this U shaped piece and then hacked out the middle, leaving 2 legs per side. I flattened out the bends at the top of these legs then drilled holes for 7/16" bolts to go through. I then bolted these legs to the pancake style mounts and compared to the other side mount (I only did 1 side at a time). It was appx 1/4-3/8" higher. I just bolted these mounts in place when I installed my engine. I am very pleased. They sit at a good height and the steering does't even come close to the oil pan. The prevoius owner achieved the same thing by putting shims under the mounts at the frame. The mounts ran approximately $20 a piece when I bought them. It took me approximately 1 hour for each mount (measure twice, cut once).2.9 How do I check the oil pressure/fuel pump switch?
This switch cuts off power to the electric fuel pump when oil pressure gets too low.
Denis (denisst78) writes:
"Pink wire: 12 volts when key is on. Purple wire: 12 volts when key is in the start position. Blue wire: output wire that goes to the fuel pump. First check if your fuel pump is running when the key is on the ON position without the engine running. If yes unplug the pressure switch and check if it's still running. If it stopped running then the switch is bad. Second check if you have 12 volts at the purple wire on the pressure switch when you crank the car. If not the wire that goes from the solenoid to the switch is bad. If yes then the switch is bad."
For a small block setup, Denis (denisst78) writes:
"Here's what I did and used:
Note that ASP will build custom pulleys (see vendor section).2.11 Why doesn't my fuel pump work?
David (monzaaddict) suggests:
"From my experience with Vega/Monza fuel pumps, I have found that the most frequent cause of intermittent functioning results from poor grounding. There is a black cable (inside the tank) that goes from the pump to the external terminal. If you can carefully disassemble the cable from the terminals, which are mounted in plastic grommets to prevent contact (and resulting sparks) with the cover plate (could not think of a better description of the part where all the steel lines lead to the outside of the fuel tank), without breaking the plastic grommets then you can clean the terminals and reassemble everything. This has worked for me."
Kevin (SoloII_74) says:
"The silicon lapping process that Chevy developed to re-hab the Vega block after an over bore basically removed a microscopic layer of the aluminum from the alloy (after boring and the finish hone to size), and this allowed the piston rings to ride on the very hard silicon particles as the wear surface. No measurable amount of wall thickness was removed in the process. You also had to have the factor plated pistons, or the pistons and walls would be scuffed.
The problem with the process is that Sunnen made the equipment and lapping compound, and they no longer have a listing for that stuff. In addition, results were unreliable when compared to the factory electro chemical etching process, and sleeving.
Bill was correct when he said that the factory bore finish, if still intact, provides a very good, long wearing (almost no bore wear) bore finish, which can be re-ringed without honing). I would be remiss if I did not point out that he was wrong about what happens when the engine overheats.
Severe overheating will disrupt that special bore finish, and cause the microscopic layer of silicon in the alloy to break down, leaving the soft aluminum alloy matrix to scuff and score, causing the type of damage which only an overbore or sleeve will fix. The incompressibility of the water has nothing to do with the scuffing or scoring of the cylinders (esp. since most of it would be flashing to vapor from the heat anyway). That is caused by the excessive heat from the overheating process.
The Vega's miniscule cooling system allowed it to overheat very rapidly when something bad happened. It usually worked like this (ie for a stuck closed thermostat): 1st stage overheat: head (or block) warps-> gasket fails. 2nd stage overheat: engine boils dry -> alloy starts to break down due to the heat of combustion, and lack of cooling. For a severe coolant leak, just go to stage 2.
Just a side note: I have seen no difference in power or durability levels in sleeved vs. stock bore Vega engine, and I have driven a cast iron sleeved engine stock class Vega to a trophy at the SCCA Solo II Nationals. I have run both types of bores in my autocross car, both in street-prepared and stock, and have not seen any difference in overall performance.
I have also helped plan and build a 300+ hp Vega Turbo 140 with steel sleeves, which were, in part, used as o-rings for the cylinder head seal.
The second attempt with a reinforced block (we split the first one in half) was still running after over 10k hard street/strip miles. It was making lots of power with reliability."2.13 How do I clean out the fuel tank?
Brew (mongoose_brew) writes:
"If you go to your local motorcycle shop, I'm sure they can help you. Motorcycles are notorious for rusty tanks. Basically, the process goes like this....
GM no longer makes ones specifically for the H-bodies, but they do sell the material. It comes in a size large enough to do two H-body hoods--just use the old one as a pattern. The retaining clips should also still be available.2.15 Where can I get replacement V8 motor mounts?
New ones: nowhere, so far; look for used ones. Some people make their own. Some companies that sell replacement mounts have shown some interest in the H-body market but have not produced any yet.
Some companies list mounts for the H-body but they don't actually work. Suspicious part numbers: 270-2292 is actually a regular GM motor mount (1978 and up G body with V8) and 270-2281 is a 3.8 v-6 motor mount (thanks to Denis (denisst78) for the info).
Don (mrdonjeffers) offers this advice on making your own:
"OK all, here is the scoop on how to retrofit a set of 68 327 Camaro motor mounts to your V8 Monza. However, there is one catch. First, you must be willing to hack up your original V8 motor mounts. If you don't want to do this then there are other options. Second, you must take your time doing what I will explain. Let's get started. You first need to have full access to your motor mounts(this means removing headers, etc. You then place your car on jack stands, making certain the car is level from side to side. Next, measure from the block (each side)to the floor, logging these measurements. Now, place a flat piece of wood on a jack and slightly lift on the engine at the oil pan. Unbolt the motor mounts from the mounting pads(not the block). Now,remove old mounts from engine block. Go to the auto parts store and purchase a set of 68 327 Camaro motor mounts ($10 each). Now comes the scary part. First, drill apart the 3 rivets that hold the flat plate of the block side of the motor mount and the clam shell that holds the rubber portion together. Seperate the two halves, giving you better access to the loop of the mount. You are going to cut(with a steel cutoff wheel in a die grinder or drill motor) your original motor mounts at the "bend" on each leg where the leg bends going into the rubber portion of the mount(not the nut end of the leg). It is critical that you cut as close to the bend as possible. Be careful to not cut downward from the bend on the leg too far towards the welded nut end. You will need as much of these legs as you can get. Now, bolt the Camaro motor mounts to the block. Remeasure your distance from the block to the floor and match the height to your earlier measurments. NOTE: since your original mounts probably let your engine sag, you may wish to raise the measurement by 1/4" to 1/2" to get the motor where you want it. Next, bolt the cut off "legs" in their position on the motor mount pads(the pads on the unitbody portion, not the block). CAUTION!!!! this next part is the most important part of all. Manuever the legs into the proper position (install the bolts, but just finger tight) on the pads and line them up so that the holes in the sides of the Camaro motor mounts will provide the most "meat" on the legs to hold the motor once you drill the holes in the legs. So, to rephrase, you are using the "legs" of your original mounts, drilling holes in them to line up with the side holes in the Camaro motor mounts and using grade 8 or grade 5 bolts and lockwashers to bolt it all together. The best way to get the markings on the insides of the "legs" of where to drill the holes is to use a 90 degree bent pick and scribe through the holes in the Camaro mounts onto the "legs" of your original mounts. Once you have the locations scribed of where you are going to drill the holes, simply unbolt the legs, drill the holes, put the legs back in place and bolt it all together. There you have it. Simple, straight forward and cheap. However, if you are afraid to cut your V8 mounts ask yourself what is better: Driving with loose, floppy motor mounts or having new rubber motor mounts. Finally, for those of you who are concerned about the strength of this set up, I am running a 350 horse 350, with 3.73 gears, Auburn posi, 15" x 8 1/2" Centerlines on z rated tires and nothing and I mean nothing moves. This set up is the best thing I have done to my Monza. Also, I recommend that you put Energy Suspension's polygraphite transmission mount in while you are under the car. You will have to cut the bottom plate off of your original tranny mount and drill a 7/16" hole in this plate to bolt into the new Poly trans mount. Once all this is done your V8 hbody will be solid and secure."