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Need Help: '85 Replacement Engine

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Old Feb 8, 2006 | 11:08 AM
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Default Need Help: '85 Replacement Engine

Looking for options to replace the engine in my '85. New crate engines preferred. Stock and moderate step up engine under consideration. This is my daily driver and I'm dead in the water. Thanks.

Note: Posted same thread in the Tech/Perf Forum just in case a member camps out there only. I hope this is OK.

Last edited by willi.anton; Feb 8, 2006 at 11:12 AM.
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Old Feb 8, 2006 | 11:30 AM
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Go your search engine and type GM Crates Engines. Take tour pick, there is large menu to order from or at least get an idea of performance desired.
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Old Feb 8, 2006 | 12:16 PM
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Search engine research and email responses from several vendors suggests that no crate engine is available for the '85, particulalry that would pass CA emissions. One email said take it to your rebuilder. I hope this is not so.
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Old Feb 8, 2006 | 12:18 PM
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there are a lot of engines that will drop in your car, but very few that are smog legal. are you trying to stay smog legal?
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Old Feb 8, 2006 | 12:24 PM
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It's my daily driver so I'm assuming I have or face trouble down the road. Do you know of any work around?

I have read some postings on the zz4 engine, but I'm not certain if these are CA smog compliant. Also, several crate packages look like they are carborated - is it possible to put the stock TPI on?

Last edited by willi.anton; Feb 8, 2006 at 12:58 PM.
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Old Feb 8, 2006 | 02:56 PM
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I seriously doubt a ZZ4 would pass emissions in California... My guess is you'll be safest going with the 260hp 350 Crate engine from GM...

GM 260hp Crate

I was worried about emissions and was likely going to opt for the 290hp version... GM doesn't recommend it for emmisions restricted vehicles...

Of course, I'm not in a hurry, and now that I've talked to a few people, I've decided to go with a 383. But I'm waiting another year before I do it, then i won't have to pass emissions and it just won't matter
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Old Feb 8, 2006 | 04:06 PM
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Originally Posted by Saisling
I seriously doubt a ZZ4 would pass emissions in California... My guess is you'll be safest going with the 260hp 350 Crate engine from GM...

GM 260hp Crate

I was worried about emissions and was likely going to opt for the 290hp version... GM doesn't recommend it for emmisions restricted vehicles...

Of course, I'm not in a hurry, and now that I've talked to a few people, I've decided to go with a 383. But I'm waiting another year before I do it, then i won't have to pass emissions and it just won't matter
I am in the same boat. I wanted to replace the engine in 85 with a crate motor and made several inquiries. The engine mentioned above is not designed for TPI, you'd have to use a carb or TBI setup to get it to work properly. GM discontinued the L98 crate motor, so finding a direct replacement will be hard.

A buddy of mine directed me to Jasper and they sell rebuilt engines. A rebuilt L98 will cost approx $2500, plus the core and shipping charges. If you can find a reputable builder, it might work out cheaper and you can tailor the engine to fit your needs better.

Just my 2 cents
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Old Feb 10, 2006 | 10:19 AM
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Back from the mechanic. He replaces the L98 engine with a "GM Target Engine" which is a L48 long block. All systems including the TPI from the old engine bolt direct to the new block. Why I asked is this solution not more widely reported. It's not a mystery he states, the L98 is essentially a L48 with the TPI. The new engine setup performs identical to the old engine. The Target Engine is about $ 1200. Sounds good to me. Original number engine doesn't seem to be of concern as the '85 may never be a classic, although it's my classic.
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Old Feb 10, 2006 | 10:40 AM
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Be sure to compare cam specs on both. The cam is likely a bit better in your 85 motor. The target stuff is usually a 1 size fits all set up to try to satisfy everyone's needs.
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Old Feb 10, 2006 | 01:28 PM
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The previous owner of my 85 coupe did the target longblock on mine with a comp cam and roller tip rockers. Mild upgrade very driveable.
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Old Feb 10, 2006 | 04:16 PM
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Originally Posted by ejscarfo
The engine mentioned above is not designed for TPI, you'd have to use a carb or TBI setup to get it to work properly.
Just replace the cam with one equal to the one in your current TPI engine and that engine will work just fine. I'm running that same engine with a larger cam, TFS heads and other goodies and it runs just fine with the TPI.
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Old Feb 11, 2006 | 10:19 AM
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Thank you to all who have responded. Off to our annual Valentines weekend, but obviously with no Vette. I'll check back in next week for additional postings. The mechanic is too busy to work on the new engine stuff, probably 2-3 weeks before we start.

I will need to dig up the cam specs, etc. on the stock engine and also the target engine. I do wonder about performance differences. The mechanic seems to feel that the primary reason the 85 is what it is is because of the TPI and engine computer. I get the point made here - the cam has to be key also.
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Old Feb 11, 2006 | 10:29 AM
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I must be missing a point here? I see chevy sbc short blocks advertised all the time for $500-600. Yes there rebuilts-but, while your pulling the engine have your heads redone-$250, get the 85 cam specs, pull the rebuild cam and install $200., new starter less than $100.
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Old Feb 11, 2006 | 10:35 AM
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GM will be a little conservative as far as claiming what would be emissions legal. THe target motor would work, but compression (8.5-1 I believe) is a little low for my tastes.
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Old Feb 13, 2006 | 09:13 AM
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On the downside, does the lower compression translate to lower horsepower and/or torque?

On the upside, does it mean using lower grade gas and thus saving a few pennies on gas?

Anybody have the engine specs and performance specs for the original 250 engine?
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Old Feb 13, 2006 | 09:40 AM
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Yes on your first two questions. On the third, actually the 85 350 was rated at 230 BHP @ 4000 RPMs, 4 inch bore-like all the rest 3.48 in stroke-like the rest, 9.0:1 compression, 86 was the same, 87 on up had higher compression ratios mostly 9.5:1 on l98s, although 91 had a
10.0:1
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Old Feb 13, 2006 | 09:54 AM
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Originally Posted by willi.anton
On the downside, does the lower compression translate to lower horsepower and/or torque?

On the upside, does it mean using lower grade gas and thus saving a few pennies on gas?

Anybody have the engine specs and performance specs for the original 250 engine?
Compression, to a point, is all good. Better emmisions and power. The trick is to run as much as the fuel will allow. Find the line and do not cross it. For me the line is 10.75 :1. On my buddies blower car 8.5:1 was his. Some lt1 guys run 11.5 :1.
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