305 to 350 ??? - Team Camaro Tech
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post #1 of 20 (permalink) Old Sep 28th, 04, 03:10 PM Thread Starter
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I am new here and also fairly new to camaros, i was wondering how hard is it (if at all possible) to make a 305 z-28 in to a 350 z-28?
will i have any major troubles?
thanks !!
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post #2 of 20 (permalink) Old Sep 28th, 04, 03:39 PM
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One of the greatest things about small block chevies is their interchangeability. You might have some issues with the heads (your car probably has the 7th bolt on the rear of the heads for the stock manifolds), and maybe with a knock sensor if you plan on keeping it functioning. Physically, a 350 will go any place a 305 fits, as externally they are identical.

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post #3 of 20 (permalink) Old Sep 28th, 04, 03:44 PM
 
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It depends???

Is your car a carb'ed car or an EFI one b/c if it is a carb'ed car, all you have to do is just change out the 305 for a good stout 350 motor.. Then make sure you have a good carb. on it...

But it is a little harder with an EFI car b/c the 305 EFI stuff isn't quite big enough stock to feed a stout 350 motor so you have to tweek the 305 EFI stuff so it will feed right..

There are guy's that know how to do it but I can't!!

Plus, you may have "smog check" issues at licensing time due to the bigger motor???

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post #4 of 20 (permalink) Old Sep 28th, 04, 05:03 PM Thread Starter
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actually i am looking into buying a '84 Z-28, it has a 305 in in but i would want to change it over to a 350. i want it to have plenty of power but still be able to drive it normally.
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post #5 of 20 (permalink) Old Sep 29th, 04, 01:41 AM
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A 350 long block will bolt in-place. Use the 305 intake system and ignition. Purchase a set of 24-25 lb injectors and change them during the swap out.

You could probably remove the smog pump and its ancilliary equipment to gain more room to change plugs. Change out any sensors you find broken, there is an exh gas temperature sensor on the egr valve. It would be advantagous to you to replace it, it's only $15.

Later on, you may have to re-program the chip for a 350 vs. 305, but, the 305 chip will run the 350.

www.thirdgen.org has ALOT of info, not there isn't excellent knowledge here, we do like helping all out in their problems, providing you don't mind us scratching our heads first.....

Iowa doesn't have smog checks yet, and probably never will in our life time. We grow the corn to feed those Aberdeen Angus cows to make them deeeelicious steaks.....

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post #6 of 20 (permalink) Old Sep 29th, 04, 06:51 AM Thread Starter
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cool, do you have a ballpark idea of what that might cost me?? thanks for all the info
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post #7 of 20 (permalink) Old Sep 29th, 04, 11:39 AM
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People at thirdgen do not care for them, but, I bought an Accel 24# set through Summit for $236 and haven't had a problem with them. They like Ford SVO injectors. To each their own, I guess.

Price, depends how deep you want to go, $500 to infinity. Keep in mind, the OE TPI system is great torque builder, but quits around 4800-5000 rpm.

Make sure you have a good Torx short height set. You'll need inb changing intake system.

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post #8 of 20 (permalink) Old Sep 29th, 04, 02:35 PM Thread Starter
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so do you thik that i could spend around $1000 total to swap out a 305 to a 350. i mean is that including buying a 350 block? and i would also have to buy injectors? it that all?
Also, could i just buy a JET chip that is for a 350 and it would work?
thanks
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post #9 of 20 (permalink) Old Sep 29th, 04, 05:29 PM
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If its an '84 camaro, then it probably has the lg4 305, but it might have the L69 HO 305. Both are carbed, which greatly simplifies things. The stock 305 q-jets will work with a metering rod change. Your biggest single expense in this case will be a engine. The price for the conversion is going to depend on many things. What you pay for the engine, what ever you want to do to it, how many spare parts you have laying around, how much of the work you can do yourself, etc. Of course, with the increased displacement, you will need a decent exhaust system to back it up, and hopefully the tranny is in good shape (otherwise thers another big chunk o' money). Another option is to throw some bolt ons on the 305, and save your bucks and build the engine you REALLY want. 3rd gens ain't much fun to work on IMO...you don't want to be swapping engines any more than you have to.

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post #10 of 20 (permalink) Old Sep 29th, 04, 05:38 PM Thread Starter
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ok, i can do all the work my self but i don't want to have a big project torn apart for ever!
so what could i do to make a 305 haul ***??
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post #11 of 20 (permalink) Old Sep 29th, 04, 05:53 PM
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Replace it with a 350 [img]tongue.gif[/img]

Seriously, it depends on the condition of the 350 you will be starting with. If you have to build it from scratch, then that $1000 won't go very far. The stock exhaust system (assuming it is stock) is insufficient for a 305...let alone a 350. But, it can be done. Even a mild 350 will run circles around all but the nastiest 305. Like I said, it really depends on what you have to work with.

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post #12 of 20 (permalink) Old Sep 29th, 04, 07:47 PM
 
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I have an '83, and out of the factory it had all that wannabe smog crap on it, but the stuff never really did anything but rob HP and take up room, so out it went. I later swapped the dying 305 for a 350, and again ran everything without the aid of the "computer" (it is actually completely disconnected now). The swap was simple as pie, as far as the engine goes, but the trannies in 3rd gens of that year are absolute chunks, so you will probably want to do a tranny swap while you are at it; get a nice TH-350 rebuilt, they are affordable enough.

Basically, once you get the engine in there, some minor things need to be done, like spiff up the exhaust to allow the new engine to work right. A true dual exhaust is very tough, and a lot of shops will say it is impossible, but I know how to do it. I won't get into that now though. About the carb, the stock 4 bbl q-jet worked very well on my 350 until it wore out and was replaced with a Holley.

If you do the swap and remove that bogus smog stuff (if it hasn't already been taken out), then you may find some "check engine" lights staying on, so just pull the bulbs, the computer is now HAL 2000: completely useless. GM made a very weak attempt in the early 3rd gens to provide some sort of smog control system, but really it did little more than simply blow air into the exhaust with a pump to dilute it. It is otherwise completely ineffective at doing anything.

Engine choice is something I suppose I should mention. Get a used engine to start, preferably one you can hear running. Aim for something late 70's so there won't be any smog crap to worry about, and try to pull it from a granny car like a sedan. This will pretty much guarantee it has not already been rebuilt and oversized, which will come in handy down the road someday when you eventually will want to rebuild it (and trust me, you WILL want to, it is in your blood to do so). The nice thing about buying the whole engine as a unti is that everything is there already, chiefly the heads are what you are after since 305 heads don't jive on a 350. Now, this will have cost you about $500 for the engine if you have played your cards right. If you want to throw some performance into it, you may invest in a mild/moderate cam, a good timing set, and perhaps an aftermarket intake, but definately cam and timing set. I say this because you can bolt on things like intakes and carbs later down the road while the engine is still in the car, cams you can't, and timing sets are not expensive and go hand in hand with a fresh cam. Then focus on the exhaust. Again, the exaust is something that can be worked on after the engine is in, so it isn't an absolute must right at the moment, you can still have fun driving while you save up some more $.

Ok, that about sums it up. I'll shut up now after having told you my life story, heheh.

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post #13 of 20 (permalink) Old Sep 30th, 04, 04:29 AM Thread Starter
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thanks
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post #14 of 20 (permalink) Old Sep 30th, 04, 03:54 PM Thread Starter
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si what if i already have a 350 block, and all i need to do is swap them. from that point on what would be involved. first pull the 305 then lower the 350 in, whats next, just start hooking things back up?
also what would it cost me from that point? i will do all of the work my self.
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post #15 of 20 (permalink) Old Sep 30th, 04, 05:59 PM
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If it is just a basic engine replacement...say you have a good running 350 ready to go in, then the cost is minimal. You'll need new exhaust gaskets for sure, and it is also a good time to replace hoses and belts if yours are even slightly suspect. Fresh plugs, oil, filters, and antifreeze. Easily under $100...assuming you don't break or mangle anything during the swap. And of course there will always be little knick knacks like the hose clamps you lose, maybe a little replacement vacuum hose (very good idea)...stuff like that.

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