305 tbi to 85' 350 carborator
305 tbi to 85' 350 carborator
hey how are ya doing?
going to throw in a 350 4bolt thats was in a 85 c10, its carbed and runs sweet with after market intake,into a 1991 rs 305 tbi m i will use the tranny I have would like to know what I need to make my gauges work, speedo is in the tranny but I plan on taking out most of the wiring like engine harness and ecu, should I leav it in and just hide it all? and my speedo is off because I have the rear end from a 1994 camaro thats posi with disc, what do I do for that? also what would be a good cam with out doing the heads? I would like to do the cam whiles its out to something mild..... I can get engine number, but where do I find the numbers for the head? I plan on using the pump in the tank with the mallory regulatror part number 4309?! is that a good choice?
so any help would be great and if you need the head numbers let me know where to look?!?!
thanks in advance
joe
going to throw in a 350 4bolt thats was in a 85 c10, its carbed and runs sweet with after market intake,into a 1991 rs 305 tbi m i will use the tranny I have would like to know what I need to make my gauges work, speedo is in the tranny but I plan on taking out most of the wiring like engine harness and ecu, should I leav it in and just hide it all? and my speedo is off because I have the rear end from a 1994 camaro thats posi with disc, what do I do for that? also what would be a good cam with out doing the heads? I would like to do the cam whiles its out to something mild..... I can get engine number, but where do I find the numbers for the head? I plan on using the pump in the tank with the mallory regulatror part number 4309?! is that a good choice?
so any help would be great and if you need the head numbers let me know where to look?!?!
thanks in advance

joe
Last edited by camaro307; Feb 24, 2010 at 12:09 PM.
Re: 305 tbi to 85' 350 carborator
Removing wiring gives no benefit, only aesthetics. If you may ever swap in another EFI engine (LTx/LSx/something new), having the rest of the harness will make life easier
LO3 cars used a buffer box to drive the speedo, as long as you keep the electric VSS in the tailhousing, your speedo will work regardless of the engine installed
You calibrate your speedo by measuring tire diameter, and factoring rear end ratio in. Once you derive the drive and driven teeth counts, pop the VSS out and swap the plastic gears
Read the chart on this site
http://www.transmissioncenter.net/sp...n_______va.htm
LO3 cars used a buffer box to drive the speedo, as long as you keep the electric VSS in the tailhousing, your speedo will work regardless of the engine installed
You calibrate your speedo by measuring tire diameter, and factoring rear end ratio in. Once you derive the drive and driven teeth counts, pop the VSS out and swap the plastic gears
Read the chart on this site
http://www.transmissioncenter.net/sp...n_______va.htm
Re: 305 tbi to 85' 350 carborator
thats great I plan on removing the harness for good but, what about oil pressure and coolant temp and fuel gauge? and whats your opion on distributors? should I use a vacumm advanced or a msd hei? pros and cons?
Re: 305 tbi to 85' 350 carborator
https://www.thirdgen.org/forums/ltx-...p-3rd-gen.html
Same year set as your 91 so you can follow this to the T
Refer to the carb board for a distributor
Same year set as your 91 so you can follow this to the T
Refer to the carb board for a distributor
Re: 305 tbi to 85' 350 carborator
ok thats GREAT, so I dont have to do anything under the dash then? this will plug into the harness connector under the hood? i wish there was a way to buy this done already! im a little confused, but I think I will get stuck a few times!!! putting the motor in will be simple, making it all work not so simple......
I am starting the swap saturday, where do I find the c100 and c207 connectors?
I think the c100 is by the relays on the driver side fire wall ? where is the c207 is that the 4 smaller that plug into the ecu? so all the work is under the hood right?
thanks pocket I thank you in advance!
I am starting the swap saturday, where do I find the c100 and c207 connectors?
I think the c100 is by the relays on the driver side fire wall ? where is the c207 is that the 4 smaller that plug into the ecu? so all the work is under the hood right?
thanks pocket I thank you in advance!
Last edited by camaro307; Feb 24, 2010 at 08:30 PM.
Supreme Member
Joined: Sep 2002
Posts: 9,192
Likes: 20
From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: 305 tbi to 85' 350 carborator
You can handle the wiring even simpler than that article. Simply remove the entire pass side harness in tact - that's all the computer controlled sensors and such. The driver side mainly contains wiring for lights, oil pressure, coolant temp, dist tach, etc. Simply remove the pass side harness in it;s entirety, and connect what's left in the same places it was removed from on the old engine (ie oil pressure above oil filter, coolant temp in driver head between #1 and #3 plugs, etc. All guages will function normal, and no pinning the connectors. There will be a few wires leftover (maybe 3-4 depending on A/C etc.) - just tuck them away.
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Supreme Member
Joined: Sep 2002
Posts: 9,192
Likes: 20
From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: 305 tbi to 85' 350 carborator
You'll need to swap to a non computer controled (ie vacuum advanced) HEI distributor.
Check the sticky atop the carb forum - answers all questions about swapping to a carb setup.
Check the sticky atop the carb forum - answers all questions about swapping to a carb setup.
Supreme Member
Joined: Sep 2002
Posts: 9,192
Likes: 20
From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: 305 tbi to 85' 350 carborator
If you have an automatic tranny, you have a locking torque converter - at highway speeds the TC locks up with the motor, so there's no slippage between tranny and motor, providing greater fuel economy and a cooler tranny. The TC is locked by the ECM - removing the ECM means no more TC lockup. So you have to either buy and install a lockup kit, or make one - again, there's a sticky on this - at the top of the carb forum or the tranny forum, don't remember which. There are many options for doing it, none better than another necessarily.
Re: 305 tbi to 85' 350 carborator
so if i leave the ecu in I dont have to do the tcc? I think I am leaving it in and I will just pull the check engine light out, what about the speed cut off how do I get around that, I have the rear end from a 1994 camaro so the speedo is way off I will change the the speedo gear but I still wanna get around the speed cut off......
Junior Member
Joined: Jun 2009
Posts: 28
Likes: 0
From: Charlotte N.C
Car: 1991 Bird
Engine: Goodwrench 4bolt 357 bore vortec
Transmission: T-5
Axle/Gears: 10 bolt posi disc w/3.23
Re: 305 tbi to 85' 350 carborator
its a great swap. i just finished mine. i think i clipped my ground wire for the buffer box. i have never used cruise so i removed it to clean up the engine bay. the only thing you will run into is "commons" between the two wireing harnesses. there are a couple but you can cut and tape them up to remove the passenger side harness. there is only 1 wire that goes to your ecm from the VSS buffer. it has nothing to do with the gauge itself. i just have to get a throttle bracket so i can get full throttle from the pedal.but it runs way better then the LO3 w/ only 3/4 throttle. the ecm controls the fuel and spark. thats what cuts out the car around 115. if its not hooked up,which it won't be you will climb well past that.........
Re: 305 tbi to 85' 350 carborator
ok got some numbers.......
block # 14010207
head # 462624
what do you guys think of the heads? i heard they are crack prone? i want to do a cam and roller rockers port polish and deck the block but the port and polish are bad with these heads ppl are saying?!?!? if i did a cam witch on should I do or do you know where to get some decent vortec heads, what about heads from a junk yard....whitch models have go heads?
mostly wanna know where to get vortec heads for a fair price
block # 14010207
head # 462624
what do you guys think of the heads? i heard they are crack prone? i want to do a cam and roller rockers port polish and deck the block but the port and polish are bad with these heads ppl are saying?!?!? if i did a cam witch on should I do or do you know where to get some decent vortec heads, what about heads from a junk yard....whitch models have go heads?
mostly wanna know where to get vortec heads for a fair price
Last edited by camaro307; Mar 7, 2010 at 01:18 PM.
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
How about a really good price? That includes everything you need to install them? And allows you to use a decent cam?
http://sdparts.com/details/scoggin-d...ter/sd8060arpm
Re: 305 tbi to 85' 350 carborator
ok so I pulled the heads off and they are for sale lol...... I called a budy and he has some l31 vortec heads and I will order the intake later......I will bring the heads in and have them cleaned, umbrella seals, screw in studs, port and polish'd
my question is...... what cam do I use for this,i will buy springs if needed..rough idle would be nice to....
I am looking for 375 or more horsies
my question is...... what cam do I use for this,i will buy springs if needed..rough idle would be nice to....
I am looking for 375 or more horsies
Re: 305 tbi to 85' 350 carborator
just respect the opion of the guys here! i was a honda guy for years and want to do a motor build right!, when im done line up and well see whos over there head! lol
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Junior Member
Joined: Feb 2010
Posts: 3
Likes: 0
From: Southern MN
Car: 84 z28 camaro
Engine: '70 355 4bolt
Transmission: TH350
Axle/Gears: 10 bolt 4.11 gears
Re: 305 tbi to 85' 350 carborator
and when ur done with ur build/swap come find me i'll be waiting haha

Junior Member
Joined: Feb 2010
Posts: 3
Likes: 0
From: Southern MN
Car: 84 z28 camaro
Engine: '70 355 4bolt
Transmission: TH350
Axle/Gears: 10 bolt 4.11 gears
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