L69 or 350?
03-29-2003, 03:00 PM
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Car: 84 Trans AM
Engine: 327
Transmission: M5
Axle/Gears: 3.73
L69 or 350?
Ok what's the consenus on a 350 swap? Can I rebuild the stock 305 motor in my 84 T/A to lots and lots of horsies economicly, or is it best to just drop in a 350 which has widely available parts?
Either way the computer system is getting disconnected and I want a purely mechanically run engine ... unless I got TPI ... but that's another story. 350 or 305? What do you guys think?
-Dave
Either way the computer system is getting disconnected and I want a purely mechanically run engine ... unless I got TPI ... but that's another story. 350 or 305? What do you guys think?
-Dave
03-29-2003, 03:47 PM
#2
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Well, they say there's no replacement for displacement. And I live by that.
You can buy a 250HP "universal replacement" 350 from GM for about $1200 with warranty and it's an all new engine. That's about 60 Hp more than your little 305 had from the factory and a boatload more torque. You can bolt all your old 305 stuff onto it and get it running for cheap and then upgrade individular parts as money permits.
You can buy even more HP for same/even less money from the remanufactured market. 300-325 HP 350s can be had for about the same money as the GM motor.
Getting your 305 up to 300 HP will cost more and it won't be as streetable as a 350 putting out the same power.
You can buy a 250HP "universal replacement" 350 from GM for about $1200 with warranty and it's an all new engine. That's about 60 Hp more than your little 305 had from the factory and a boatload more torque. You can bolt all your old 305 stuff onto it and get it running for cheap and then upgrade individular parts as money permits.
You can buy even more HP for same/even less money from the remanufactured market. 300-325 HP 350s can be had for about the same money as the GM motor.
Getting your 305 up to 300 HP will cost more and it won't be as streetable as a 350 putting out the same power.
03-29-2003, 05:37 PM
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It isn't really economical to try to get high HP out of a 305. You can get the same HP cheaper out of a 350.
If your short block is OK, there's lots of things you can do to improve the L69, without getting into a rebuild. Even if it needs bearings, as long as the rings are OK, you can fix that easily and cheaply.
Take the heads off, and port them thoroughly; add a decent cam; and put a set of headers on it. There's really not that much to be gained by changing out the carb and distributor to non-computer ones, unless they're defective; that's not what's limiting your HP. You'll need to do both of them at the same time, which is rather a chunk of change for something that can be easily accomplished some other way.
You can get your crank reground and put a set of bearings in it, and a new oil pump, and probably get lots more miles out of it, if the rings are OK.
If the rings are bad, then the block needs bored, and you have to buy pistons. There's no sense whatsoever in doing that to a 305. At that point, look for a 350 block to rebuild, if you're the type that would do that; or a 350 motor.
I would not choose the "250 HP" 350 myself; it's got dished pistons, 993 "Hecho En Mexico" smogger heads, and a 929 cam. In reality, it won't make any more HP than what you have now, once it's installed in your car, maybe even less. If you want to buy a whole new motor, rather than rebuilding one, look at the ZZ4; it's a vastly better motor than the "Goodwrench" fleet replacement POS. Of course it also costs more... but you tend to get what you pay for.
For a point of reference: I have a 305 in my car right now, that I slapped together to get it through California emissions while I lived out there. It has the stock air cleaner, stock carb, stock distributor, stock intake, stock exhaust from the cat on back except that the cat has been replaced and the muffler is a Dynomax, stock radiator, all stock sensors and valves and what have you all hooked up and operating, because that's what they look for in CA (they have a book that shows where each one is and what it's supposed to be hooked to, and they go over the car looking for every one of them). The only signifcant changes are that it has Edelcrock TES, a Comp XR264HR cam with 1.6 rockers, and a set of old double-hump heads I had laying around (there's more power left in them, you could do better than these particular ones with your 305 heads, if you worked at it). It put 209 HP to the rear wheels, which is about 260 at the crank. Made the Mustang owners that were standing around the dyno at the time look kind of green, since their cars were doing about 195-205 at the wheels that day.
Did I say "stock" enough times to make the point that those parts you can see aren't costing you HP?
If your short block is OK, there's lots of things you can do to improve the L69, without getting into a rebuild. Even if it needs bearings, as long as the rings are OK, you can fix that easily and cheaply.
Take the heads off, and port them thoroughly; add a decent cam; and put a set of headers on it. There's really not that much to be gained by changing out the carb and distributor to non-computer ones, unless they're defective; that's not what's limiting your HP. You'll need to do both of them at the same time, which is rather a chunk of change for something that can be easily accomplished some other way.
You can get your crank reground and put a set of bearings in it, and a new oil pump, and probably get lots more miles out of it, if the rings are OK.
If the rings are bad, then the block needs bored, and you have to buy pistons. There's no sense whatsoever in doing that to a 305. At that point, look for a 350 block to rebuild, if you're the type that would do that; or a 350 motor.
I would not choose the "250 HP" 350 myself; it's got dished pistons, 993 "Hecho En Mexico" smogger heads, and a 929 cam. In reality, it won't make any more HP than what you have now, once it's installed in your car, maybe even less. If you want to buy a whole new motor, rather than rebuilding one, look at the ZZ4; it's a vastly better motor than the "Goodwrench" fleet replacement POS. Of course it also costs more... but you tend to get what you pay for.
For a point of reference: I have a 305 in my car right now, that I slapped together to get it through California emissions while I lived out there. It has the stock air cleaner, stock carb, stock distributor, stock intake, stock exhaust from the cat on back except that the cat has been replaced and the muffler is a Dynomax, stock radiator, all stock sensors and valves and what have you all hooked up and operating, because that's what they look for in CA (they have a book that shows where each one is and what it's supposed to be hooked to, and they go over the car looking for every one of them). The only signifcant changes are that it has Edelcrock TES, a Comp XR264HR cam with 1.6 rockers, and a set of old double-hump heads I had laying around (there's more power left in them, you could do better than these particular ones with your 305 heads, if you worked at it). It put 209 HP to the rear wheels, which is about 260 at the crank. Made the Mustang owners that were standing around the dyno at the time look kind of green, since their cars were doing about 195-205 at the wheels that day.
Did I say "stock" enough times to make the point that those parts you can see aren't costing you HP?
03-29-2003, 07:29 PM
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Car: 84 Trans AM
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Axle/Gears: 3.73
Originally posted by RB83L69
Did I say "stock" enough times to make the point that those parts you can see aren't costing you HP?
Did I say "stock" enough times to make the point that those parts you can see aren't costing you HP?
-Dave
03-29-2003, 08:50 PM
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Car: 84 Trans AM
Engine: 327
Transmission: M5
Axle/Gears: 3.73
What about the Vortec centerbolt heads for the 350, I've heard good things about them. Could those with some rolling rockers be a good Idea? I could use them one the 305 until I find a 350 to rebuild and then use them there. Is that possible? When I worked with Mustangs we'd put 351 heads on a 302 and that worked incredibly well.
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