Hello to all!!

I have been reading all of the information available on this site for several months now and WOW!! Every article on a TBI build has been absolutely incredible information for building a performance engine. Thank you everyone!!! This is my first post so I hope I give all of the info you need about the build.

I have started a 1988 350 TBI build. My goal is to achieve 300hp and rpm band of 1000-5500. Not going to race or anything just some daily driving and cruises.

I have elected to go with the following:

1988 350 4-bolt main (bored 0.040) (Completed)
Selead Power 9.5:1 Pistons (Completed)
Vortec 062 heads (Already have Alex's Parts Springs, Locks, and Shims for larger lift cams)
GM TBI Intake (Completed)
EBL Flash (Soon)
Lunanti Vodoo or Comp Cams
Self Aliging Rokers - Comp or ProForm
Ac/Delco Fuel Pump ep381
JBA Headers / y Pipe (Completed)
Flowmaster Cat Back (Completed)
Wideband O2 - Innovative (Soon)

So here are some of my Questions:

1. When selecting a TBI unit, I have an oppurtunity to PU a Holley 502-6 TBI used for a good price. Cant seem to find info about the injectors tho... I think they are the 55 or 64pp/h . Should I consider this or a tbi unit from e.performace.parts on e*ay? or redo my original TBI unit?

2. I am looking for opinions on these two cams:
Lunanti- 10120701LK (Old # 60101)
Comp- 12-256-4
Please do not hold back on opinions!!!

3. Does anyone know RPM range on the GM Performace TBI Vortec Intake? I purchased this with the 062's for a GREAT price and I am hoping the intake is within the rpm range i am looking for. I also am aware that i will have to have the intake bored to match and aftermarket TBI unit.


Well I think that is all i have for now!! Thanks again to everyone for all of the fantastic info on this site!!

 

Dont get the Holly TBI. Get a bored GM unit. Parts are all over the place and injectors are much cheaper. You will need to play with a few sets before its all over and doing that with a holly will cost you ALOT!
Keep it factory (ish)

 

'316

1) Holley TBI unit is mixed bag - some like it and some curse it. To reach 300HP power level will require fuel and air. To reach this with TBI will require 50mm bore unit and VRFPR with EBL. I would go for 64 lb-HR units running 15 - 25 psi FP range to start with. As you improve engine tune you can raise FPR 1 to 2 psi to take care of lean spots at higher RPMs to keep injectors out of 80% duty range. You can always swap in BBC 80 psi injectors if needed.

2) Both these cams are mild enough for street operation - it will not take much with EBL to dial in. Both cams will work fine in 350 sized engine with 062 heads. You may want to consider WBO to help with tuning (with EBL).

3) GM TBI Vortec intake is fine from idle to 5000 RPM. Your upper limit will be your heads.

//RF

 

I am still sorting this out myself. I have a 502-6 sitting in the garage. Paid $80 for it (used, of course) but the wire harness is melted, and the base gasket has been used and is embossed. I anticipate not needing the thick (and EXPENSIVE!) Holley base gasket which has the tapered-entry holes to clear the larger throttle plates, as I intend to use the 454 TBI-to-4-barrel adapter. The Holley wire harness showed up today. Now I have to create an OEM connector-to-Holley connector adapter harness.

There are "early" and "late" injectors and injector pods for the Holley replacement TBI units. The "early" injectors are identified by the rounded, rubber cap that the wiring connects to. The "late" injectors are identified by the flat stamped-steel retainer plate that holds the injectors in the pod. You are, hopefully, looking at a later-style 502-6 rather than the early style. You're also going to want the "air distribution ring" that isn't in the photos below. I'm told it makes a considerable difference in mixture distribution.

An "early" 502-6 TBI can be converted to the later-style injectors and pod; but the cost is around $350 if buying the parts new. (Two injectors at over $100 each, and the replacement pod kit at just under $100. Note that the late-style 502-6 injectors are rated by Holley at 60 pounds per hour at 12 psi, and 85 pph at 21 psi.

Early-style TBI, photo taken from the 502-6 page of the Holley web site:


Holley replacement TBI with early-style injectors and pod




Late-style TBI; photo taken from the 502-9 page of the Holley web site.


Holley replacement TBI with late-style injectors and injector pod

 

No matter where you get it ask them if the IACV is pre- set or you will have problems with idle from the start.


Most likely you will have to set your timing to stock.
Then set minimum idle speed and when you do the procedure it will also include re-setting the IACV.


This must be done or the ECM will be receiving the wrong signals.