Help with header install

[Chillin014]

i'm about to get started workin again. Really all i have left to do is plug that hole and tighten the header / reinstall the battery etc.

I found on google someone was asking where the oil pressure unit was on a 350 and the answer was that on the big blocks they are on the bottom near the oil filter like mine. I am not that knowledgable in american cars but I thought the 350 was considered a small block, I didnt realize there was a big and small.

either way, i've got both...I just wish there was some kind of book or source that would show all the variations of the 350 block so I could figure out WHY I have both. Its hard figuring out everything the previous owners did to this car.

I dont know if this is OEM but the exhaust on the driver side was smashed down to about an inch in diameter to clear that cross member...talk about restriction. Also, the EGR valve wasnt connected to anyting and stuck in the almost closed position...so hopefully these headers give me some horsies

 

[85 Cutlass Brougham]

Okay, as for big and small blocks there are a few basic variations. What you have is a GEN I Small Block Chevy ( SBC for short). This engine family was introduced in 1955 as a 265 ci engine and has had several displacements over the years, but all are essentially dimensionally interchangeable. Displacements include: 262, 265, 267, 283, 302, 305, 307, 327, 350 and 400 ci in stock installations. There is also a HT 383 crate engine that is available from GM, but was never installed stock in anything. This does not include all of the aftermarket variations in displacement using non stock parts. There are two Big Block designs that were installed in passenger cars over the years. The first is the "W" head engine that was introduced in 1958 as a 348ci engine. This grew to a optional 409 ci engine in 1961. This engine was used in trucks as well as cars, but in cars was only in full size models. It was phased out of production in cars in 1965 when it was replaced by the "Mark IV" Big Block. This is the engine most people think of when talking about a BBC. It was available in 396, 402, 427, and 454 CI displacements in cars. Trucks had a 366 engine in addition to the car engine sizes. The last passenger car application of this engine was in 1976 (IIRC) when it was phased out for emissions and economy reasons. Unlike the W engines, it had wide availability and was available in every car line except the Corvair, Vega, Chevette and Monza during this time. This engine was used in trucks through the 90's when it was replaced by modified versions of this design, the Mark V and Mark VI engines.

As for your crossmember/ exhaust question, this is not factory. GM never put true duals in a G body so it was butchered to look like it had them. Normally, the exhaust Y's into a single catalyst under the passengers seat and then may or may not Y back out to duals depending on the model.

As to why you have both things, remember that the 350 is not specific to any model of car but the block is generic and there are several options as to how things hook up. This is intended as you can put a SBC from any year into a SBC car of any other year. All SBC's had the front mount provisions that the '55 265 had even though they were replaced long ago by side mounts. 350's were available in the following cars: Chevelle, Nova, Camaro, Impala, Caprice, Kingswood, El Camino, Corvette, Monza ( California only as the 267 would not pass smog in 1976), Bel Air, Monte Carlo, and full size trucks. They came out in 1967 and were exclusive to the Camaro that year. They have also been used in other GM brands as GM made their drivetrains more generic starting in the latter 70's.

 

[Chillin014]

ah thanks for all that information! I can see where there's a bunch of small differences.
I loosened the header and got a picture of where the extension actually does thread into the lower hole. Like you said (or someone said) the extension doesnt really look factory so I dont know what was in this hole before but there is no way the oil pressure unit would fit there thread-wise and clearance-wise without that extension. ANYWAY I will be heading to the hardware store shortly to pick up a bolt.

I completely forgot about the a/c compressor situation. I bought this recommended bracket from summit since the stock bracket cant be used but I am absolutely clueless as to how this thing goes on...If nobody is familiar with this I'll get a picture of it but its making me think that this piece just doesnt fit here and was recommended based on the assumption i have some kind of other accessory set-up.(automatically by the website).

Okay, as for big and small blocks there are a few basic variations. What you have is a GEN I Small Block Chevy ( SBC for short). This engine family was introduced in 1955 as a 265 ci engine and has had several displacements over the years, but all are essentially dimensionally interchangeable. Displacements include: 262, 265, 267, 283, 302, 305, 307, 327, 350 and 400 ci in stock installations. There is also a HT 383 crate engine that is available from GM, but was never installed stock in anything. This does not include all of the aftermarket variations in displacement using non stock parts. There are two Big Block designs that were installed in passenger cars over the years. The first is the "W" head engine that was introduced in 1958 as a 348ci engine. This grew to a optional 409 ci engine in 1961. This engine was used in trucks as well as cars, but in cars was only in full size models. It was phased out of production in cars in 1965 when it was replaced by the "Mark IV" Big Block. This is the engine most people think of when talking about a BBC. It was available in 396, 402, 427, and 454 CI displacements in cars. Trucks had a 366 engine in addition to the car engine sizes. The last passenger car application of this engine was in 1976 (IIRC) when it was phased out for emissions and economy reasons. Unlike the W engines, it had wide availability and was available in every car line except the Corvair, Vega, Chevette and Monza during this time. This engine was used in trucks through the 90's when it was replaced by modified versions of this design, the Mark V and Mark VI engines.

As for your crossmember/ exhaust question, this is not factory. GM never put true duals in a G body so it was butchered to look like it had them. Normally, the exhaust Y's into a single catalyst under the passengers seat and then may or may not Y back out to duals depending on the model.

As to why you have both things, remember that the 350 is not specific to any model of car but the block is generic and there are several options as to how things hook up. This is intended as you can put a SBC from any year into a SBC car of any other year. All SBC's had the front mount provisions that the '55 265 had even though they were replaced long ago by side mounts. 350's were available in the following cars: Chevelle, Nova, Camaro, Impala, Caprice, Kingswood, El Camino, Corvette, Monza ( California only as the 267 would not pass smog in 1976), Bel Air, Monte Carlo, and full size trucks. They came out in 1967 and were exclusive to the Camaro that year. They have also been used in other GM brands as GM made their drivetrains more generic starting in the latter 70's.

 

[megaladon6]

the reason you would have 2 oil senders is 1 pressure sensor and 1 low pressure ignition kill switch. i have the large clunky sender on my car, behind the intake, i had to grind down the intake to make it fit.

 

[Chillin014]

the reason you would have 2 oil senders is 1 pressure sensor and 1 low pressure ignition kill switch. i have the large clunky sender on my car, behind the intake, i had to grind down the intake to make it fit.

thanks. and damn i wouldnt want to grind on the intake manifold too much if thast what it takes :?

so the larger one would be the pressure sender? i mean the only connection for this is to the gauge in the dash.

Alright I've plugged the hole and my current battle is this A/C bracket. The instructions say "if your a/c is mounted on the left side use the bracket" But how am i supposed to know which side the left side is? Why the hell couldnt they just put "passenger" or "driver side". When referring to the right side header they talk about the starter so i'm guessing the left side is the driver side. If thats the case, YES, my a/c compressor is mounted on the left side but I still have no idea how this bracket goes in here.
http://store.summitracing.com/partdetai ... toview=sku

 

[R/T kota]

Drivers side = left
Passenger side = right

 

[megaladon6]

it looks like the slots at the opposing ends are for the header bolts. it should fit over the header tube on the outside of the flange.

i did extremely little grinding. the outer ring of the oil sender hit a vertical rib. using a dremel works great and you're only clearancing it 1/8in at most.

 

[Chillin014]

okay thanks guys. I really appreciate the quick replies on this forum..i was on elcaminocentral and those guys never respond or do very slowly. this forum is alot better.

anyway. The a/c bracket DOES look like the two slots would be two header bolts but it completely doesnt line up...the bolt holes are much closer together. I believe the stock bracket will work if i cut one of the legs off it. I'll take some before and after pictures. the only reason it doesnt fit is because it the header pipe is too thick for its opening. i'll see what i can do. be back in awhile.

edit-- I modified the stock one like i said I would and it worked fine. For some reason I could not get the power steering pump-to-crankpulley belt very tight, yet the main belt that goes around everything was decently tight. Everything seems to be fine. I might have some rattling under throttle but its hard to tell since im running open headers at the moment. I guess thats why they recommended to replace the motor mounts...i'll do that eventually. This was a HUGE job. Seriously...this was the most involved project i've done short of a motor swap and transmission swap in another vehicle.

 

[85 Cutlass Brougham]

Well, the bracket says it is for the axial compressor. If you have the radial compressor it will not work in all likelihood. The radial compressor is the short one that is about 8 inches in diameter. The axial is the older style and is longer, about 10-12 inches long by 4-5 inched in diameter. It goes past the beginning of the valve cover and should say Frigidaire on it. The Radial is about 3-4 inches wide and says Harrison on it.

Here's my 85 Compressor with a bracket attached. It is the later Radial style.

Back of Compressor:

A pic of the brakcets for the compressor with the compressor and reinforcing strut off.

Front view:

Top View:

I can take a more specific pic if you like. As you can see, I have headers too but my setup uses all of the original GM brackets. The only alteration is a set of small spacer sleeves on the outermost two header bolts that compensate for the difference in width between the header flange and the stock cast iron manifold's mounting flange. If you are wondering, my headers are Edelbrock's smog legal shorties with a corresponding Y pipe. They came with all of the hardware to hook up the A/C, smog and O2 sensor.

You may wish to post a good set of pics of your engine bay so we know what you have. A left, right and center pic set would be the best. Anyhow, I hope this helps a little.

 

[Chillin014]

ah i see i see. Mine definitely looks like the radial style but I will have to confirm and check tomorrow. The modified stock bracket seems to have worked fine. I'll get some pictures up tomorrow

I went to drive the car and it had a horrible bogging, the whole power band felt like crap and revved very choppy and slow. My timing is off a little bit but the car ran decently before the header swap so the first thing that crosses my mind is that maybe I put a spark plug wire in the wrong spot even though I labeled them and everything. Either that or i didnt plug one in all the way, its hard when the header pipes are in the way. I'll have to re-check tomorrow...I cant imagine running such a freeflowing exhaust would cause this after having such a restrictive one, right?

ALSO, for some reason my oil pressure gauge still works despite taking out that unit and plugging that hole. But now the gauge instead of reading a little above 30 is reading near 60. I dont know if its wiggin' out or whats up with it. I changed the oil today as well and after turning the car off and adding the 5th qt the oil pressure went up to the 60 area...is this normal?

thanks for the pics