Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 1 of 2 12 LastLast
Results 1 to 15 of 20

Thread: Advise needed, planning a 383 build for a 1988 C1500 Pickup

  1. #1
    Carb and Points!
    Join Date
    Mar 2019
    Posts
    9

    Advise needed, planning a 383 build for a 1988 C1500 Pickup

    Hello I am new to the idea of tuning the factory TBI and have been cruising this board for awhile. One question I have in my head is "What are the limits of cam size/vacuum signal that will work with the map sensor in this type of fuel injection?" I am not looking for something radical, just a peppy truck engine that will pull a load.

    Plan so far
    350 block bored .030 (already finished)
    383 kit with 6 inch rods (already have)
    afr 195 heads 75cc chambers (to give 9.5 to 1 compression) or equivalent due to the price of AFR's
    Roller Cam (no size determined yet)
    Good long tube headers and dual exhaust.

    Any other thoughts would be welcome. Truck has the 1227747 PCM I believe

  2. #2
    Fuel Injected! PlayingWithTBI's Avatar
    Join Date
    Dec 2018
    Age
    65
    Posts
    126
    Sounds like a fun build. As much as the 383 will breathe you'll need a bored out (46mm) TBI with higher pressure or maybe even a 50mm from a 7.4. On the bottom of this link you can estimate what you may need...

    http://www.tciauto.com/tc/racing-calculators

    Here's where I bought my 46mm with 18# spring. It comes with new IAC, and TPS, with voltages preset.

    https://www.ebay.com/str/sprperformance

    If you can afford it try the Dynamic EFI conversion

    https://www.dynamicefi.com/EBL_Flash.php

  3. #3
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    4,113
    So many options, so many opinions, but I recognize budget is a factor.

    Reground camshafts can save money, often a performance camshaft profile can be ground into an original camshaft (but there are limits) I sure there are several members with Pro / Con OPINIONS about using a reground camshaft. For a mild built daily driver 1993 K1500 5.7 liter with TBI (weighing in a 5200 lbs.), I opted for an ultra low cost reground Vortec 5.7 liter roller camshaft (stock lift / stock duration). With the savings from the reground camshaft, I invested in some ultra expensive 1.6 ratio roller tip rocker arms. I was able to tune the reground camshaft / 1.6 ratio rocker arms to a performance of 0 MPH to 60 MPH is about 7 seconds (which is the kind of performance that gets up and goes from a stop light to the end of the freeway on ramp with a smile).

    Used SBC parts are not unique, rare or hard to find. Generally performance SBC parts are becoming more abundant, with the rise in LSx engine popularity.

    Hopefully you can budget for a better performing head than the 195's (my own personal opinion).

    The 7.4 liter 670CFM throttle body is a good option, but can create some headaches.

    I posted an article several years ago "1227747 R.I.P." so I'm not going to hide my opinion that the factory 16197427 is a better computer for a performance engine on a budget.

    I'm also Opinionated that it's good plan to budget for tuning equipment, simply stated tuning will optimize the performance of the parts decided on.

    I'm also Opinionated that an "Optimal Chip" Can Not be programmed with the information "Tell us what modifications were done". I'm so flat out Opinionated about TBI performance chips, that I BOLDLY SAY use TunerPro RT or just keep chasing tail lights like everyone else who doesn't use TunerPro RT!

    dave w

  4. #4
    Fuel Injected! PlayingWithTBI's Avatar
    Join Date
    Dec 2018
    Age
    65
    Posts
    126
    Plan so far
    350 block bored .030 (already finished)
    383 kit with 6 inch rods (already have)
    afr 195 heads 75cc chambers (to give 9.5 to 1 compression) or equivalent due to the price of AFR's
    Roller Cam (no size determined yet)
    Good long tube headers and dual exhaust.
    Is your block an 88 too? Is it set up for a roller cam?

  5. #5
    Carb and Points!
    Join Date
    Mar 2019
    Posts
    9
    Quote Originally Posted by PlayingWithTBI View Post
    Is your block an 88 too? Is it set up for a roller cam?
    THe Block I have at the machine shop is out of a 1993 but has been drilled for the roller setup. I have a 1993 4wd 2500 that I robbed the engine from. If the computer would be better I might could try to adapt it. I have wondered if a newer pcm would be better since 1988 was a long time ago computer wise. I would think a newer one with a newer processor would think faster

    I am planning on a roller cam. Was looking at the Comp 08-465-8, but open to suggestions.

    I was looking at possibly getting the TBI bored when I get closer. I am not sure at the moment which injectors the TBI has, nor if they will feed a bigger healthier engine.
    I have already installed the 1996 Vortex fuel pump in the tank (because the stock one died).

  6. #6
    Fuel Injected! woody80z28's Avatar
    Join Date
    Nov 2011
    Location
    Walton, NY
    Age
    33
    Posts
    165
    I just googled the stock TBI and it's quoted as good for 450-480cfm. Is this figured with fuel spraying through it? Carbs too? Cause the fuel itself takes up space.

    That cfm calc shows my truck should have about 500cfm. But with an MPFI conversion and dry throttle body maybe a wet 470 is enough?
    80 Camaro Z28 - 550hp AFR 383 / T56 6spd (Holley HP EFI)
    91 Beretta "SS" - 260hp 3400 MPFI / HM282 5spd (7730/$A1)
    94 Silverado Z71 - 300hp Vortec 357 TBI / NV4500 5spd (7427/$0D)

  7. #7
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    4,113
    Quote Originally Posted by Redtires019 View Post
    I have a 1993 4wd 2500 that I robbed the engine from. If the computer would be better I might could try to adapt it. I have wondered if a newer pcm would be better since 1988 was a long time ago computer wise. I would think a newer one with a newer processor would think faster
    The 1993 TBI computer is most likely part number 16168625, which has a baud speed of 8192. The 1988 TBI computer has a baud speed of 160.

    dave w

  8. #8
    Fuel Injected!
    Join Date
    Sep 2014
    Posts
    86
    Save some money for your transmission;)

    If you want a cheap cam- get the BIGGER of the LT1 variety.
    Last edited by dfarr67; 03-08-2019 at 04:25 PM.

  9. #9
    Fuel Injected!
    Join Date
    Mar 2012
    Age
    32
    Posts
    87
    Quote Originally Posted by Redtires019 View Post
    THe Block I have at the machine shop is out of a 1993 but has been drilled for the roller setup. I have a 1993 4wd 2500 that I robbed the engine from. If the computer would be better I might could try to adapt it. I have wondered if a newer pcm would be better since 1988 was a long time ago computer wise. I would think a newer one with a newer processor would think faster

    I am planning on a roller cam. Was looking at the Comp 08-465-8, but open to suggestions.

    I was looking at possibly getting the TBI bored when I get closer. I am not sure at the moment which injectors the TBI has, nor if they will feed a bigger healthier engine.
    I have already installed the 1996 Vortex fuel pump in the tank (because the stock one died).
    I have a comp cam 08-466-8,. made 375 FHWP/420ft lbs FWTQ on the dyno in a 355 with vortec heads. it also had stamped steel 1.5 rockers, i would highly recommend full rollers. has about 100 hours on it. engine is getting recamed and going in a boat so cam needa a new home.

    http://www.compcams.com/Company/CC/c...?csid=208&sb=0
    Last edited by tayto; 03-09-2019 at 02:46 AM.

  10. #10
    Fuel Injected!
    Join Date
    Feb 2015
    Location
    New Zealand
    Age
    50
    Posts
    223
    375 FHP/420ft lbs FWTQ.....was that with TBI on it or a carb?

  11. #11
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    4,113
    Stock L31 Vortec cam specs
    10241264 casting number
    Intake lift- .414 with 1.6 rocker arms .442
    Exhaust Lift- .428" with 1.6 rocker arms .457
    Intake duration @.050"- 191*
    Exhaust Duration @ .050" - 196*
    Lobe Centerline- 111 Degrees

    I like the 111 Degrees for the Lobe Centerline of the L31 camshaft (smooth idle / good vacuum). I like the added lift the 1.6 rocker arms provide to the L31 camshaft. Roller tip rocker arms provide a more accurate lift ratio than stamped steel rocker arms. Depending on brand, stamped steel rocker arms have been measured at 1.42 ratio not 1.5 ratio.

    The LT1 for the 94-96 Buick Roadmaster, Chevrolet Caprice, and Cadillac Fleetwood have the same Lobe Centerline of 111 Degrees as the L31 camshaft with slightly more lift .418 / .430.

    dave w

  12. #12
    Fuel Injected!
    Join Date
    Sep 2014
    Posts
    86
    I think there was another cam for the Z28/Corvette- the 383 should swallow that with no issues.

    I had a 355 TPI with a CC flat tappet, very noisey lobes, ended up using a stock vortec roller- with a nice tune it worked very well with 1.6 RR. Not a fan of CC ever since.
    Last edited by dfarr67; 03-09-2019 at 09:21 AM.

  13. #13
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    4,113
    For tuning purposes, I often use a factory camshafts and related spark tables. For example using a LT1 camshaft matched with the LT1 spark tables programmed in the chip, is a good plan for a "Starter Tune". The final "tuned chip" might have all, some, most, or none of the original timing table (that called tuning). The original TBI timing table works well with the original TBI camshaft. It's fair to say the original TBI timing table can be improved with the original TBI camshaft too.


    dave w

  14. #14
    Carb and Points!
    Join Date
    Mar 2019
    Posts
    9
    Quote Originally Posted by dave w View Post

    Hopefully you can budget for a better performing head than the 195's (my own personal opinion).
    What head do you prefer? I am open to considering all options. I need a 76cc head to work with the pistons I have and the 195 runners should be close for a torque 383 IMO, I am not brand loyal though for this I would prefer Aluminum heads, the price tag on the AFR's has held me off so far.

    Quote Originally Posted by dave w View Post
    I posted an article several years ago "1227747 R.I.P." so I'm not going to hide my opinion that the factory 16197427 is a better computer for a performance engine on a budget.
    Can you post a link to it? I have searched for it but only thing I have seen close to it is this. If their is an advantage to wiring in a newer PCM I am willing to attempt it. I do not know the shape of the PCM in this junk 1993 K2500, but I can rob the wire harness. WOuld have to turn off the transmission controls since I have a pre electronic 700R4.


    Quote Originally Posted by dave w View Post
    I'm also Opinionated that it's good plan to budget for tuning equipment, simply stated tuning will optimize the performance of the parts decided on.

    I'm also Opinionated that an "Optimal Chip" Can Not be programmed with the information "Tell us what modifications were done". I'm so flat out Opinionated about TBI performance chips, that I BOLDLY SAY use TunerPro RT or just keep chasing tail lights like everyone else who doesn't use TunerPro RT!

    dave w
    I have read TBI's info page. It has me wondering if I can get the stock injectors to do the job a little. I do not have to have the truck running today so I have the time to do this the right way. The transmission has been recently overhauled and has the corvette servo and the sonnax smart shell upgrade in it to btw.

  15. #15
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    4,113
    Please disregard my comment on the AFR 195 Heads, I was mistakenly thinking about TBI head casting 193 (I don't know how I did that).

    16197427 Upgrade Link: http://www.gearhead-efi.com/Fuel-Inj...out-Directions! The 1988 harness is retained by re-pinning the wiring at the computer connectors.

    Define stock injectors? Stock 7.4 liter injectors flow more fuel than stock 5.7 liter injectors.

    dave w

Similar Threads

  1. Replies: 0
    Last Post: 08-22-2017, 11:59 AM
  2. Planning TBI swap on 455 Olds
    By Thainglo in forum Introductions
    Replies: 1
    Last Post: 02-12-2016, 06:58 PM
  3. 1988 GMC C1500 engine/trans into 1973 C20 Crew Cab
    By O-B-1 in forum GM EFI Systems
    Replies: 24
    Last Post: 10-13-2015, 03:39 PM
  4. New guy trying to build '47 chevy 5 window pickup
    By oldfoop in forum Introductions
    Replies: 2
    Last Post: 03-20-2014, 01:23 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •