What would you do (engine selection)?
Thread Starter
Instructor
Joined: Mar 2006
Posts: 143
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From: Jacksonville FL
What would you do (engine selection)?
Guys,
Im in a unique situation. I have a 71 Convertible 350/270hp AT car.
I plan on swapping the engine for something with more umph.
I own a salvage yard, and have the following three candidate engines for a build, what do you suggest?
1. 350 carb engine out of 1984 half ton truck, good runner.
2 piece seal.
2. 350 TBI motor out of 1992 half ton truck, good runer.
1 piece seal.
3. 1994 Firebird LT1 350. Good runner, aluminum heads.
I own an intake that will adapt either option 2 or 3 to a carb.
I plan on running a T56 transmission behind it, so running option 1 adds about 350 dollars for a flywheel (which weights 35lbs!!) to adapt to the six speed, whereas I can use the factory flywheel/clutch/pressure plate off of the 94 Firebird of option 2 or 3.
I would like to have performance similar to the ZZ 383/425hp engine available for GM. Which engine would get me there reliably and not bust the budget? Or would it be cheaper to just bite the bullet and buy the engine from GM?
Thanks,
Richard
Im in a unique situation. I have a 71 Convertible 350/270hp AT car.
I plan on swapping the engine for something with more umph.
I own a salvage yard, and have the following three candidate engines for a build, what do you suggest?
1. 350 carb engine out of 1984 half ton truck, good runner.
2 piece seal.
2. 350 TBI motor out of 1992 half ton truck, good runer.
1 piece seal.
3. 1994 Firebird LT1 350. Good runner, aluminum heads.
I own an intake that will adapt either option 2 or 3 to a carb.
I plan on running a T56 transmission behind it, so running option 1 adds about 350 dollars for a flywheel (which weights 35lbs!!) to adapt to the six speed, whereas I can use the factory flywheel/clutch/pressure plate off of the 94 Firebird of option 2 or 3.
I would like to have performance similar to the ZZ 383/425hp engine available for GM. Which engine would get me there reliably and not bust the budget? Or would it be cheaper to just bite the bullet and buy the engine from GM?
Thanks,
Richard
Le Mans Master
Joined: Apr 2004
Posts: 7,106
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From: Newark DE
i'd consider going with the LT1, stroke it out to a 383 stroker, and forget the carb - keep it as a fuel injection unit.
The LT1 was a real nice motor and if you turn it into a 383 stroker it only gets better
The LT1 was a real nice motor and if you turn it into a 383 stroker it only gets better
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
The LT engine is harder to find parts for and other than reverse coolant flow, there are really no reasons to go with it. Parts for it are more expensive and your head selection is seriously limited. If you can find it at a reasonble price, go with one of the SB2 engines - those suckers make some serious power IF you can get the computer, etc. worked out. Otherwise, stroke a conventional smallblock or pick up a 400 block and build a torque monster.
Thread Starter
Instructor
Joined: Mar 2006
Posts: 143
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From: Jacksonville FL
I actually have the salvage car the LT1 came out of, Boofers, and its the same car thats donating the six speed.
Frankly Ive been scared of the fuel injection route, I have very little experience with it. One mistake I made is that I did not keep the engine wiring harness and computer when I sold the front end off the car.
One of the reasons I was considering going w the LT1 or the TBI engine was that I could reuse the flywheel/clutch/pressure plate I already have that came w the car whereas a 2 piece seal motor would require a different,expensive flywheel.
Frankly Ive been scared of the fuel injection route, I have very little experience with it. One mistake I made is that I did not keep the engine wiring harness and computer when I sold the front end off the car.
One of the reasons I was considering going w the LT1 or the TBI engine was that I could reuse the flywheel/clutch/pressure plate I already have that came w the car whereas a 2 piece seal motor would require a different,expensive flywheel.
Thread Starter
Instructor
Joined: Mar 2006
Posts: 143
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From: Jacksonville FL
One question Id like answered is can any of these engines be built dependably for less money and achieve the performance of the zz 383?(roughly 5k)
For the LT1, that would mean me buying a new harness and computer as well as other FI modifications (fuel lines, fuel pump).
For the LT1, that would mean me buying a new harness and computer as well as other FI modifications (fuel lines, fuel pump).
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
Originally Posted by hap1971
Im in a unique situation. I have a 71 Convertible 350/270hp AT car. I plan on swapping the engine for something with more umph. I own a salvage yard ...........Thanks,Richard
Since you own the yard ... Suggest you wait for a nice LS vehicle to arrive ... get its injected motor, ECM & harness ... LS motors make serious HP just the way they are. Or, edelbrock makes a carb intake for LS. I'm a dyed-in-the-wool fan of chevy iron ... but it seems to me that LS modded rods are the future. Several others on this forum have done LS swap and they seem to be most pleased ... AFAIK, none of em had the yard-owner advantage ($) you have.
If you have original matching motor/trans ... DO keep it ... but it a secure spot where it CANNOT be mistakenly sold off/picked over.
Thread Starter
Instructor
Joined: Mar 2006
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From: Jacksonville FL
The LS cars w factory 6 speeds are still going for top dollar at the salvage auctions (at least in N Florida). The automatic cars are significantly cheaper, but its my understanding that I really need a MT car if I want to do a MT conversion with the LS1. Also, the LT1/TBI/Carb engines all share motor mount locations and most mounting points, has any body came out w a mounting kit for the LS motor or would I have to fabricate (not good at fabricating).
Once upon a time I had a 79 corvette and did the T56 conversion to a carb engine, and really enjoyed it. I was hoping to duplicate that success on my 71, but people are suggesting that FI might bring about even more joy. My question is can FI bring this joy more cost effectively than a built up carb engine?
Once upon a time I had a 79 corvette and did the T56 conversion to a carb engine, and really enjoyed it. I was hoping to duplicate that success on my 71, but people are suggesting that FI might bring about even more joy. My question is can FI bring this joy more cost effectively than a built up carb engine?
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by hap1971
has any body came out w a mounting kit for the LS motor or would I have to fabricate (not good at fabricating).
My question is can FI bring this joy more cost effectively than a built up carb engine?
My question is can FI bring this joy more cost effectively than a built up carb engine?
Last edited by jackson; Aug 1, 2006 at 11:20 AM.
Thread Starter
Instructor
Joined: Mar 2006
Posts: 143
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From: Jacksonville FL
Thank you everyone for the advice.
It seems there are two camps -
go with the LT1, or go buy an LS1
Nobody likes the carb motors anymore it looks like.
Ill pick up an LS1 next time one rolls through the auction.
Any particular make/year thats preferable as far as the conversion goes?
(98-02 Camaro/Firebird, new GTO, or Corvette?)
It seems there are two camps -
go with the LT1, or go buy an LS1
Nobody likes the carb motors anymore it looks like.
Ill pick up an LS1 next time one rolls through the auction.
Any particular make/year thats preferable as far as the conversion goes?
(98-02 Camaro/Firebird, new GTO, or Corvette?)
Thread Starter
Instructor
Joined: Mar 2006
Posts: 143
Likes: 0
From: Jacksonville FL
I have a 454 truck motor, circa 1979, just got the truck but havent had a chance to run the engine yet. Probably get to it later this week. Truck was a DUI haul in from the police, so hopefully its a good engine.
Richard
Richard
Safety Car
Joined: Dec 2004
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From: San Diego CA
Originally Posted by hap1971
I have a 454 truck motor, circa 1979, just got the truck but havent had a chance to run the engine yet. Probably get to it later this week. Truck was a DUI haul in from the police, so hopefully its a good engine.
Richard
Richard
Out of the previous 3 I'd say the LT1 would be good. Take your pick on whether or not you want to keep the fuel injection. It's a good FI setup, but it can be tricky to make it work without the wiring and computer. If you want to get it done sooner than later, you can put it in first without the fuel injection then later acquire the parts to complete the fuel injection setup and do that.
It's not too hard to make an LT1 a real screamer.
Pro
Joined: Jan 2005
Posts: 535
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From: Southaven MS
Don't forget, they make a carburetor intake for the LT1 as well. From what I understand the reverse cool allows the engine to have a little more compression without detonation(cool water hits the heads first). I also understand that the iron LT1 heads from the Impala SS, and roadmasters flow a little better than thier aluminum counter parts(stock vs. stock of course). Of course you can run more compression with the aluminum head version.
Just some food for thought.
Just some food for thought.
Drifting
Joined: Sep 2004
Posts: 1,959
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From: North Bend Ohio
Originally Posted by hap1971
I have a 454 truck motor, circa 1979, just got the truck but havent had a chance to run the engine yet. Probably get to it later this week. Truck was a DUI haul in from the police, so hopefully its a good engine.
Richard
Richard
BigBlockk
Later.....
Le Mans Master
Joined: May 2006
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From: League City Tx
I would use the TBI 350. Its one piece seal, roller block. Buy a 383rotating assy for it and have a local shop do the machining and clearancing. You could piece the bottom end together for $1500 or less. Then spend the money on the heads, $1500 for AFR 195 SE. A good sized hyd roller like the XE294HR and an air gap intake/825 demon. You could make 450-500hp for under $4500. Or you could go BB. Get ready to spend some real cash then though.
Le Mans Master
Joined: May 2006
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From: League City Tx
BTW late model LT1s are junk. I supposed if you were going to gut it and install all aftermarket rotating assy they would be ok but. The heads don't flow, the intakes suck.. Once you convert all that sh*t to stuff that actually performs, you could have gotten out cheaper buy doing the TBI block and not had to mess with that stupid reverse flow coolant. Why do you think GM **** canned the LT1 after only 4 yrs? Sh*tty design, no power and weak bottom ends.
Now if you want to do an LS1 conversion, that is the most bang for the buck by far. Its a lot of work but nothing will make power like that LS1. Take a stock LS1 and stick a cam in it and headers on it, custom tune it and it will make 400hp at the wheels. You will spend $5k+ on a sbc to get that kind of power and the LS1 will run forever and still get 17mpgs..
Now if you want to do an LS1 conversion, that is the most bang for the buck by far. Its a lot of work but nothing will make power like that LS1. Take a stock LS1 and stick a cam in it and headers on it, custom tune it and it will make 400hp at the wheels. You will spend $5k+ on a sbc to get that kind of power and the LS1 will run forever and still get 17mpgs..
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
BTW, look for an 01-02 LS1, they have bigger injectors, better intakes(same as LS6), better rod bolts, tighter piston to cylinder clearances and better casting heads. Use any decent cam, like a TR 224 or TR 230 if you are running the T56, they will still offer good tq and make close to 400rwhp. Thats a 12.20 car on slicks.