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94 obs 4.3 to 97 vortec 350

This is a discussion on 94 obs 4.3 to 97 vortec 350 within the Engine Swaps forums, part of the Performance category; I've got a 94 scsb obs and the original 4.3 bit the dust the other day at 270,000 miles.It blew ...

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    Registered User jbrenneman13's Avatar
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    94 obs 4.3 to 97 vortec 350


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    I've got a 94 scsb obs and the original 4.3 bit the dust the other day at 270,000 miles.It blew a head gasket and overheated cracking the block beside the freeze plug in the process.Since I gotta pull the engine I figured it would as good of time as any to swap to a V8.My dad had a 350 vortec that he was planning to put in another project he was working on but has since decided to go a different route.He said I could have it for my OBS.For right now the 350 will remain pretty much stock as I gotta get my truck back on the road as soon as I can.I got my truck pulled in the garage last night and plan to pull the v6 on saturday.I plan to run the TBI system and 4l60E tranny.Heres a list of what I have got so far.

    350 vortec from 97 truck
    Gasket set (might as well replace all the gaskets before hand)
    350 EFI distributor
    OBX shorty headers
    My current exhaust setup-Stock Y pipe 3'' intermediate from the Y in to a SI/DO Flowmaster 40series with with 2 1/2'' tailpipes out the sides behind the wheels.
    350 fuel injectors for TBI
    SBC Vortec Dual plane 4bbl intake w/ TBI adapter
    350 Radiator
    And some other odds and ends
    AFPR
    Throttle body rebuild kit

    I still need to get an ECM and this is where I'm having a little trouble.Do I get my current ECM programmed or do I need to get a V8 ECM to give a starting point for the tune?Where is a good place to have a tune done?I havent checked anywhere locally yet to see if anybody can do a tune for me.I would like to put a bigger cam in before I drop the motor in if my budget will allow.What cam would you guys suggest to use that I could get away with and not have to do any mods to heads?This is my daily driver and most of driving consists of in town driving.I rarely run it out on the interstate.I would like to stick with a roller cam if at all possible.I was thinking possibly an LT4 hot cam or something along those lines.

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    Registered User Doober's Avatar
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    Re: 94 obs 4.3 to 97 vortec 350

    Hot cam will require either machining for more lift or beehive springs. If you don't want to mess with head work or changing springs I would go with a cam under .475" lift with 1.5 rockers, and under 215 on the intake unless you change the torque converter. You will definitely need a tune regardless, and more fuel pressure than the stock 13-15psi.

    '92 Sierra (TBI 383/Vortecs/Comp 08-412-8/EBL/4L60/3.08s), '78 Malibu (Vortec'd 350/4-speed/2.29s), '87 Pontiac Fiero GT (2.8 v6/5-speed)


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    Registered User Doober's Avatar
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    Re: 94 obs 4.3 to 97 vortec 350

    http://www.summitracing.com/parts/CRO-00409LM/

    also...
    www.dynamicefi.com - you would basically need a 2nd TBI ECM to run the engine, but you can tune it yourself as you drive it.

    '92 Sierra (TBI 383/Vortecs/Comp 08-412-8/EBL/4L60/3.08s), '78 Malibu (Vortec'd 350/4-speed/2.29s), '87 Pontiac Fiero GT (2.8 v6/5-speed)


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    Registered User jbrenneman13's Avatar
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    Re: 94 obs 4.3 to 97 vortec 350

    Ok well it looks like I'm going to be doing a rebuild on the 350 vortec before I go any farther.I'm thinking I am going to go 30 over with stock crank and rods.I will most likely have the heads gone through to make sure they are in good running order.So while they are at the builder I will have them modified for a bigger cam.I wasnt expecting to have to do a rebuild right now but it looks like I have no choice.

  5. #5
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    Re: 94 obs 4.3 to 97 vortec 350

    Have the guides machined for more lift and screw in studs if you want to go with a bigger cam.

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