Anyone know the difference between the 350 engine in standard caprices and the 350 engine used in the Police version? I understand that the TBI unit was the same
but the police version used 68#injectors versus 61# injectors. Did the police version get a different cam and heads?
I was thinking the police version might be a good swap for my 91 RS 305 TBI if it has better heads and cam than the standard 350. Anybody know?
Thanks....bob


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91 camaro RS convert
t-5
open element air cleaner
TBI spacer
Flowmaster muffler

 

Yes, the police version had a different cam, but its still pretty weak... I dont remember the specs off the top of my head. My dad has one of those cams on a shelf in his shop, and no he's not selling it. He's using it for another car.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Believe it or not, that Caprice engine (police package or not) has the exact same internals as the ZZ4 engine. I verified each part number in the GM Performance parts calalog and they are identical. Nodular iron crank, 2nd generation pink rods, and 10:1 hypereutectic pistons. The heads and cam are different, of course.

How do I know this? I have that same Caprice engine sitting in my '92 RS. I added better heads and cam, but will also be using a Holley 670tbi and intake. See my sig:

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'92 RS, ZZ4 10:1 350, Edelbrock 6085 heads, Crane 208/214 467/482 cam, GM/LT4 1.6 true roller rockers, Holley Projection TBI intake, Holley 670 TBI, SLP/Jet-Hot 1-5/8" headers, Catco 3" cat, Flowmaster 3" catback, Hughes 2500 stall converter, stock 700R4, Auburn Pro posi w/3.42, 17x9" SS rims w/BFG tires, Medium Quasar Blue w/white SS stripes, 48,000 miles....

 

So you mean to tell me that my Caprice shortblock that I just dropped in my Camaro, is a ZZ4 in disguise ?!! This looked like it was carbed, but it is a full roller motor with "X"s marked on the rods.

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92 Z28 L98 350
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Ported and polished heads, ported stock TPI base, ported plenum, Comp Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation 110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster catback with LT1 style tips, MSD coil & wires...

"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)

 

Is the Caprice engine 4-bolt mains? The ZZ4 is... I think he meant the internals, not the block itself.

 

That is correct. The Caprice block is a 2-bolt, the ZZ4 is a 4-bolt.

Don't let the 2-bolt block concern you. I've never heard of a block coming apart at the main caps, have any of you? 2-bolt vs. 4-bolt only comes into play when you're cranking out 500+hp or turning 6500+rpm all of the time (like NASCAR, NHRA or similar).

Anyone that has the Caprice motor has the same rotating assembly as the ZZ4, which means that you have the same great foundation for power as well!! Add better heads and a good cam and you can exceed the ZZ4's performance. The ZZ4 heads are no big deal. According to flow numbers I've seen, almost any good aftermarket head will exceed the ZZ4/L98's flow numbers, even with ported ZZ4/L98 heads. The ZZ4 cam is a bit too agressive as far as available vacuum goes from what I've heard.

My reason for choosing the Caprice motor over the ZZ4 was the cost and the ability to change the heads and cam without throwing money away. My brand new complete engine including Edelbrock heads, Crane roller cam and GM/LT4 1.6 roller rockers, fully assembled was $3,000, which is $300 less than what the ZZ4 sells for, and it's exactly what I wanted.

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'92 RS, ZZ4 10:1 350, Edelbrock 6085 heads, Crane 208/214 467/482 cam, GM/LT4 1.6 true roller rockers, Holley Projection TBI intake, Holley 670 TBI, SLP/Jet-Hot 1-5/8" headers, Catco 3" cat, Flowmaster 3" catback, Hughes 2500 stall converter, stock 700R4, Auburn Pro posi w/3.42, 17x9" SS rims w/BFG tires, Medium Quasar Blue w/white SS stripes, 48,000 miles....

[This message has been edited by Scott C (edited October 05, 2000).]

 

The main difference between the caprice and the cop police car wasn't the engine. The cop police car used a different chip, different injectors, had a different rear axle ratio, and from what I know larger tires. The speed limiter on the Caprices were tuned up for the Police packages. When you drop in your motor, everything from your old 305 will directly bolt up and all mechanical components and electrical components will work, but you MUST change your chip!

-=-mike

 

Well, they may be some better than usual parts, but they're not the same as the ZZ4 in all aspects. They're not the ZZ4 rods. The ZZ4 has the powdered metal LT1 style rods. Not the pink rods. The heads to me seem very anemic. They're 1.94/1.50's, but the intake ports are very strange. They're not open at all. They start looking normal but about 1/2" into each port, there's a large bump on the pushrod side that extends about 1/4" into the intake port and sort of looks like a wall in the side of each. I will say that the castings look much smoother than the normal TPI or TBI heads I've seen as far as flow surfaces. The cam looked healthier than usual, so that may well be a ZZ4 peice. And yes, it was a 2 bolt.

This is from an 89 Caprice police engine that we disassembled a couple of weeks back. The pistons also look the same as the 9.7 CR pistons that were in the Z originally as well. I would say however, that it would be a pretty good reciprocating assembly base for a buildup.

Todd


[This message has been edited by Todd91SS (edited October 05, 2000).]

 

Hey burntblues, thanks for the info. Would the chip from a caprice work if I don't make major mods to the engine? I was thinking of the stock caprice crate engine, headers,
intake manifold, maybe a turbocity redo of my throttle body and a caprice chip.
Its got to be 50 to 70 hp better than my 305 and sounds like the easiest swap.
Any thoughts on this are appreciated...bob

------------------
91 camaro RS convert
t-5
open element air cleaner
TBI spacer
Flowmaster muffler

 

I have to disagree, but I'm only going on my setup. My vacuum is just fine. I have speed density, too. The 208/221 duration cam isnt very big at all. Its a very nice mid-range cam for a street car, in my opinion. The only problem is the .474/.510 lift, which will require changing to high performance springs.

 

Todd91SS,

I mistakenly listed the ZZ4 rods as "pink rods" when in fact they are "2nd design powdered metal rods". The Caprice engine has the exact same rotating assembly as the ZZ4, including the rods. Check the part numbers. I never said that the block, heads, or cam were the same. That is why I changed my heads and cam to better pieces and the 2-bolt block is not a concern for me.

The ZZ4 cam having too little vaccum is due to the 110* LSA.....from what I've been told.

My cam has almost identical duration, but less lift and a 112* LSA.

All I'm saying is that the '93 Caprice engine #12513151 is a good start for a performance street engine. Granted, the Caprice engine as is with the weak heads and cam are no great shakes. Just like the heads and cam on LO3, LO5, LG4, L69 and even L98 engines are not the greatest for performance. Who keeps stock heads and cam on an engine if they want better performance anyway?

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'92 RS, ZZ4 10:1 350, Edelbrock 6085 heads, Crane 208/214 467/482 cam, GM/LT4 1.6 true roller rockers, Holley Projection TBI intake, Holley 670 TBI, SLP/Jet-Hot 1-5/8" headers, Catco 3" cat, Flowmaster 3" catback, Hughes 2500 stall converter, stock 700R4, Auburn Pro posi w/3.42, 17x9" SS rims w/BFG tires, Medium Quasar Blue w/white SS stripes, 48,000 miles....

[This message has been edited by Scott C (edited October 06, 2000).]

 

You've been told wrong. ZZ4 cam is 112º LSA. Its 208/221, .474/.510, and 112º LSA.

 

That's strange. Why would two different custom chip makers tell me to stay away from the ZZ4 cam due to it's low vacuum? This was in discussion about a custom chip for my 350/TBI setup.

I don't disagree with you, just confused now.

 

Just my 2 cents, ZZ3-4 cam is ok but the advertised duration is rather high. Go with a Comp CAMS similar ground (sorry no PN but call CompCams) and you will be better of. All the GM HP cams have too much adv duration and not enough lift (compared to Comp)

 

I am confused too. I talked to TPIS about
boring my TBI and they said more lobe seperation was better for TBI cars.
I don't know but can anyone clear this up?

------------------
91 camaro RS convert
t-5
open element air cleaner
TBI spacer
Flowmaster muffler

 

most aftermarket companies will tell you more lobe seperation because then they can sell you a chip and fool you into thinking it works great since the car will actually run ok with wider lobe seps (more vacuum) the closer the lobe sep and more duration the harder to just make any ol chip work (lobe sep/duration, are intertwined here in their vacuum characteristics, wider lobe sep wont do anything if say the duration comes up such that the overlap is the same as it might be on a smaller cam with shorter lobe sep) they will tell you it "cant be done" but that is just BS that means tHEY cant do it.

Im running a 112 lobe sep cam with 214/224 duration in a TBI 305 according to them this woudlnt work well at all but my idle is smooth as glass and the car hauls A$$. Course i do my own chips

sorry to get a little off the original topicjust helping rsilver out

 

Thanks pablo, I got off my own subject too,
but I was confused on that Lobe seperation issue so asked the question.Thanks bro.......bob

------------------
91 camaro RS convert
t-5
open element air cleaner
TBI spacer
Flowmaster muffler

 

I don't know if the caprice chip would be best for your setup, with the changes that you have in mind. It may be, it may not. What I did was I called up Hypertech and told them that I would need a custom chip. They faxed a form, which I had to fill out. 2 days later, they called back and gave me the number for the chip that they make that will suit your needs. the thing that they don't tell you is that they also get a list of GM chips that will also work, though not quite as well. I used the GM chip # that they gave me and ordered the chip from the dealer for $40.00. I think Hypertech also has a stock of these chips, though they may be at a slightly higher price. You should know though that when you do custom mods, you will usually require a custom chip. When I put in the 350, I left everything pretty stock on the motor, so thats how I could get away with the caprice chip. I think you probably could too. The chip # that Hypertech gave me was: 16143692 It listed for $75.00.

Good luck on the rebuild!
-=-Mike