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Carb OR TBI on Vortec 350 swap.

A

aerofxr

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Hi, folks I'm new to this forum but after reading some posts I think this will be a valuable source of information.
I'm old school, like points and condenser old school. My first build was a 1970 351C in my families four door 1970 Torino. I had no business attempting it with my limited knowledge at the time. But, by golly, it worked and was very fast. It all ended sadly though with my younger brother losing control and "flying" it into a ditch. He was fine.
In any case, I want to get your opinion's here. It involves a fairly common swap from not too long ago. I've got a 1991 K2500 w/a TBI 350. I acquired a very good condition 1997 Vortec 350 from a salvage yard. That engine came from a Suburban and it appears to have been driven like the mom's kid mover it probably was here in Utah. I'm trying to decide which is more likely to have a good outcome. I have researched this subject enough to know what's involved with either choice I make. Using the TBI or using a 600-650 square bore carb. I like the TBI and I'm not building a monster so if it turns 320 HP that's fine. I know about the higher-pressure pump and pressure regulator requirement, vacuum issues, probable chip burn etc. and have a Jegs vortec dual plane manifold that won't have the EGR. I'd like to keep the EGR but I can't and that's just one reason for the chip burn. Keeping the TBI I'll get computer controlled (to some point) fuel from the two injectors for mileage and a reliable and easy fuel system to work with. A carburetor will eliminate all the sensors so they just get rolled up and tucked away, potentially more power choices with the cam chosen. What I want is lower range torque and HP so the cam lifts are going to be around .450-.470 and LSA of 112-118 I've measured the stem seal to retainer clearance on the L31 iron heads and I'm good to about .480 w/ .050 safety margin. I might go with Alex parts retainer and spring kit to eliminate any clearance issues.
So, has anyone had experience with this swap? What would you do differently knowing what you know now? If you went with the TBI system are you glad you did or did it turn out to be a royal pain? Any opinions welcome
Thanks
 
I had a '90 K1500 with a 4.3 v-6 which I swapped in a 350 TBI with Vortec heads. Jim Pace Performance sold the heads and a special intake just for this engine/head combo. Hedman made the ceramic coated headers I used. It idled perfectly. When cold ran perfectly. After it warmed up, it stuttered a little when taking off from a stop, but once I got out of that little slump each time, it ran like a scalded dog.

I never got the stutter out of it. A couple guys made a couple programs for it that I tried, but to no avail. Someone on here could probably figure it out, though. Lots of brain power with some of these fellers.
 
TBI for me every time.
I guess the Vortek can be a good one too with the proper uprated components.
Also, IIRC, the FI engines is limited to the type of cams that will work well with that system.
Welcome to the forum FXR. Is that the model of a Harley You ride ?
Carb and points is great on My old Harleys, My four wheel vehicles, I want TBI.
 
Funny you mentioned the cam. I had completely forgotten about that part of the venture until I read that in your post. First cam was in on the engine stand. Engine all buttoned up and pretty. Didn't run worth a crap after it got stuffed into the truck, called vendor (Jeg's or Summit - can't remember which) told them which cam I had by their recommendation and they said they sent me the wrong cam - sent for carb, not TBI. They sent another and we installed it. Obviously this time I'm irritated - paint on my bolts is now chipped and block has antifreeze running on my fresh paint. Second cam - still ran like crap, called vendor again. Oh, you have a 350? We sent you a cam for a 305 - you don't want to run that other one. We'll send you the right one this time. By this time, I had concluded that I should have put the engine together with Velcro...
 
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