VIN Y - 89 Brougham

[Daniel Kuczek]

I know there's a difference in power in the VIN Y vs. VIN 9 Northstars, but I just found out that there are also Y and 9 carbureted 307's in the Broughams. I've never heard or seen anything about two different engines, but I tried to buy parts for the car yesterday and both AutoZone and Advance list both engines. The car does not appear to have towing or livery packages - at least the codes don't seem to be there on the sticker in the trunk. Can anyone help? Thanks in advance.

[JasonA]

Do you have an '89 Brougham with the VIN 9 Oldsmobile 307 engine? That would be a first that I've ever heard of! It's been rumored (and GM shows it) that some Cadillacs received VIN 9 307 engines, but nobody I ever have talked to has seen one. I used to have an '84 Cutlass, and conversed via an email list with other 1980s Oldsmobile fanatics, much like this forum.

The difference in the VIN Y and 9 307 engines were few, similar to the Northstar engines.

The camshaft was the main difference in the 307 engines. .400/.400 lift for the Y engines and .440/.440 lift on the 9 engines. The heads were the same, as were the exhaust manifolds (usually). The intake manifolds were the same, and the basic carburetor was the same, with some tuning differences, like secondary metering rods. In the Oldsmobiles, the 9 engine came exclusively with the TH200-4R transmission and a 3.73:1 axle ratio. I would expect that the VIN 9 Cadillacs also had a 3.73:1 ratio, so GM would only have to federally certify one powertrain package for emissions.

The power for the two engines is:

Y: 140 hp, 255 tq

9: 170 hp, 250 tq

Those numbers will vary depending on source and model year, but that's the generally accepted numbers for 1985 and later Olds 307 engines. Please get back to me if you have a Cadillac with the VIN 9 engine from the factory.

Thanks,

[KHE]

My off the cuff guess would be that you have the 140 HP VIN "Y" engine but to be sure, check the 8th digit of the VIN - it will be either "9" or "Y".

The 5.0L engine was rated 170 HP in '91 and '92 but those engines were 305 cu-in (Chevy) engines with throttle body fuel injection.

[Daniel Kuczek]

No, mine's a Y. Of course, now I'm wondering how difficult it would be to convert it to the 9 specifications!

[KHE]

KevinW built up a 7.6L Olds engine for his Brougham - he can offer more details than I can other than it is a rocket....

[jschunke]

I found this website most informative on the Olds 307:

http://www.442.com/oldsfaq/ofe307.htm

Just like the Northstar there's not much you can do to the 307. It may only have

140 hp, but its got over 250 ft/lbs of torque. If you want some ball busting torque then go for the Olds 455.

To make a 307 VIN Y into a VIN 9 (high performance), just use the following:

Part Part Number

Long Duration cam shaft 22519934

High Rate Valve springs 22510372

Harmonic Balancer 417142

Rochester 4MV carb 17083553

Dual Snorkel Air Cleaner Assy. 25042690

Intermediate Exhaust Pipe 22516113

Muffler and Tailpipe Right 22526204

Muffler and Tailpipe Left 22526205

[JasonA]

That's right -- there are very few differences between the two engines. The only thing I would worry about, if you're interesting in swapping parts, is the camshaft.

On the other hand, you can swap in a larger Oldsmobile motor and have it bolt, literally, straight in. Specifically, all small block Oldsmobile engines are the same externally (260, 307, 350, 403), and share the same stroke. The main difference is the bore. So you could build you a nice Olds 350 or 403 and swap that puppy right in. You can even use the computer and all electronics you have on the 307. Your main issue will be the intake/exhaust manifolds. 1985 and later 307 engines had roller camshafts, and intake manifolds (A5 castings) with much smaller ports (to promote high velocity for good torque characteristics). While this isn't necessarily good for power, it still worked well for a good torquey engine -- and it will provide mounting locations for all the engine sensors. An intake manifold from a 403 probably won't have all the sensor locations you need. You can use an A4 aluminum intake from a 1980-1984 307 engine, which may have all the sensors you need (but maybe not).

The exhaust manifolds on 1985 and later 307s were also different from the rest of the small block Olds crowd. They're stainless steel tubular design, with pretty danged small ports. You should be able to use the 403's exhaust manifolds if you go this route.

I swapped a '79 403 into an '87 Buick Regal with the 307 engine. If you have any questions about this swap for your Caddy, I'd be happy to answer them for you.

[KevinW]

Installing a VIN 9 camshaft alone will likely make your Brougham slower since the 200-4R was calibrated to upshift at 3500 rpm at WOT. In order to make use of the power range, you'd need to change the final drive ratio to 3.23:1 or higher, modify the transmission governor for 5000 rpm upshifts, and possibly install a 2400 rpm stall converter.

My vote is for a 350-455 Olds V8; this is the simplest, most cost effective and refined route to better acceleration performance.

[JasonA]

You can easily adjust the shift points of the 200-4R transmission with the tension on the TV cable, mounted on the carburetor. I did this on my '87 Regal. The thing was in overdrive (4th) at 25 mph already. I cinched up on that TV cable, and it'd hold 3rd at least until 40 mph (it had a 3.08:1 axle). The shifts were also much firmer. If I had kept the car longer, I'd have installed a shift kit. Good call on the torque converter -- that's another "modification" with the VIN 9 engines (they came with higher stall converters).

The 400/425/455 Olds engines could be installed, but then you're getting into some different parts (since the deck height is about 2" higher on a big block Olds). The engine mounts should be the same, but you may not be able to bolt the 200-4R to it (not sure though). Personally, I'd go with a TH-400 if I were putting a big block in the car. Another consideration with a big block is clearance with the A/C accumulator and fan box. This was a problem with the G-bodies, and I'm not sure if it would be a problem with the D-bodies or not. A small block Olds (260/307/350/403) is quite literally a direct swap (given the caveats I listed above).

[KevinW]

Adjusting the T.V. cable may move the part throttle shift points around to some degree, but in my view, there is only ONE correct adjustment. Full T.V. pressure must correspond to WOT; this ensures the line pressure is at its highest when the engine is at maximum output and WOT detent downshifts are possible. When the T.V. is "tightened" beyond the correct adjustment, the part throttle shift points will increase, however, as soon as you hit WOT, it will just ratchet back to the correct position. The governor, along with the shift valve springs, main line pressure, etc., controls the WOT or maximum T.V. pressure shift points. Regardless of the T.V. adjustment, the maximum WOT shift points for a 307/200-4R D-car will occur at 3500 rpm (since peak power is at 3200 rpm).

The 400/425/455 is about an inch taller. The R4 A/C compressor to waterpump bracket will need to be lengthened, and the A/C and alternator belts need to be ~2 inches longer. The 200-4R will bolt-up just fine, and could probably benefit from more aggressive shifts to deal with the increased engine torque. No HVAC box clearance problems in the D-car. The cast exhaust manifolds work fine. A THM400 wouldl make the car slower, consume more fuel, and would require a different transmission crossmember and a custom driveshaft.