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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: jackerekson on January 01, 2017, 11:06:39 pm

Title: Vortec 5.7 paired to th350?
Post by: jackerekson on January 01, 2017, 11:06:39 pm

Have a 79 c30 I'm doing a lot of work to, it's getting a 91 front clip solid axles and I shortened the frame to fit a short box, have a 97 burb the tranny went out on so I decided to convert to the fuel injected 350, if I keep the th350 in it what would I need to do to make that work?


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Title: Re: Vortec 5.7 paired to th350?
Post by: VileZambonie on January 02, 2017, 05:02:49 pm

The VSS signal

Title: Re: Vortec 5.7 paired to th350?
Post by: fitz on January 04, 2017, 07:25:12 am

Painless wiring makes a VSS that attaches between your trans & speedo cable for about $150. 

Title: Re: Vortec 5.7 paired to th350?
Post by: SkinnyG on January 04, 2017, 09:59:31 am

Jags that Run makes a VSS that attaches to the backside of the pinion flange for about $90.

You could get a programmable MegaSquirt ECU for less than a carburetor, and have full control over any modifications you do.  Doesn't need a VSS at all.

Title: Re: Vortec 5.7 paired to th350?
Post by: VileZambonie on January 04, 2017, 05:39:36 pm

I should clarify, it won't have a vss signal but that does not mean you necessarily need it unless you are concerned about DTC's being set or TCC operation (if its a TH350c)

Title: Re: Vortec 5.7 paired to th350?
Post by: SkinnyG on January 04, 2017, 07:20:17 pm

In my reading, apparently the VSS has a role in cruise tuning, as well as deceleration and makes lower engine speed more stable.  I have no first-hand experience though.

Title: Re: Vortec 5.7 paired to th350?
Post by: jackerekson on January 08, 2017, 10:34:53 am

Could I just pull the whole wiring harness out of the burb and lay it into my truck without hooking up the transmission cable or will it throw the ecu off?


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Title: Re: Vortec 5.7 paired to th350?
Post by: SkinnyG on January 08, 2017, 11:18:57 am

My understanding is it will throw the ECU off.  A code, plus driveability issues.  But I may be wrong about your particular combination. The project I am wiring up EFI for, needs the VSS for sure.

Title: Re: Vortec 5.7 paired to th350?
Post by: VileZambonie on January 08, 2017, 02:40:06 pm

Is it a TH350 or TH350C? Does it have the square connector on the drivers side?

Title: Re: Vortec 5.7 paired to th350?
Post by: Sinister.454 on January 10, 2017, 12:58:53 pm

Sucks because youll need to rig up a electric fuel pump...adds $$ and headaches to the job.
Better to buy a crate engine and run the standard manual pump.
Ask me how I know...