New Engine Help

**Engine07** · 01-29-2015

My list of plans for getting my truck back to new are still progressing, lol. I am getting about ready to start the new engine in the next few months. Gathering parts already. I am unsure of the exact horsepower of a build this style but am looking for input on what any of the experienced tuners here think or would do differently. And also what all I will need to do to the fuel system to upgrade to run the new engine. As this truck is a daily driver I will also not be opposed to pay someone to help with the tuning. I know I'm not experienced enough to tackle the tuning alone and get it close to start lol. Engine is a 350 vortec block I have that needs bored. I am going to be .030 over and was scared if the tbi could support it bumped to 383 so if it can let me know your thoughts please as this needs to be reliable not wanting to go to carb. I'm thinking 355ci. The heads looked at are promaxx 185cc intake vortec style. Never used promaxx before so let me know what you think if you have please. Chevy magazine had them rated at 430ft lbs 408 hp on a 350 build with a cam slightly larger than I'm looking at. Cam choice is lunati hydraulic roller. Specs are Advertised Duration (Int/Exh): 279/287Duration @ .050 (Int/Exh): 213/219
Gross Valve Lift (Int/Exh): .447/.471
LSA/ICL: 112/108
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range:1500-5500
Looking at 1.6 rockers to get lift to .477 intake/.502 exhaust. I contacted promaxx and was told that their heads had viton seals, 2.02 intake/1.6 exhaust and could take .575 lift and springs almost exact match to lunati recommendation. And edelbrock performer rpm intake with tbi adapter. Also looking at approx 9.5 compression with forged pistons. Any suggestions on changes you would make? If promaxx heads are any good? Hp thoughts? Where to start tuning? Fuel system changes? Bored tb or 454 tb or holley 670, etc? I have very limited experience with tbi as all of my previous builds have been carb. Thanks in advance. Also am running 95 k1500 with 4l60e, 3.42 gears. Also going to 4.10 gears soon. 7427 ECM currently using $0D.

**BLG355** · 01-30-2015

If you do a search in my name, you will find some threads that may be useful. I am working on a 95 k1500 as well, similar build. A few of the threads will address several of your questions.

Do you have any tuning equipment yet? I actually got screwed by TBIChips and came here and was very fortunate to work with one of the best tuners ever. He got me going and I bought equipment from Moates.com to be able to try things myself, which is the way to go IMO and if you want to get it really close, it's probably about the only way.

BLG

**Engine07** · 01-30-2015

I have the tuning equipment just not the knowledge of what all to change yet lol. I'll keep searching around. Thanks. I talked to tbichips and after reading some stuff by Dave and eaglemark I decided the knowledge base was great here and decided better off to do it on my own with some help

**Engine07** · 02-03-2015

My best guess is somewhere around 340-350hp potential from this combo with the tbi. All of the calculations I'm coming up with are either leaning towards 454 injectors around 16-17psi or 350 injectors around 30psi. What would be your recommendation? Can the 454 injectors be reduced enough in the tuning that I will be fine with them at an idle if I go adjustable regulator and up them to 17? Sry for all the questions I have been trying to research and seem to come up with a lot of mixed stories.

**BLG355** · 02-03-2015

I am currently running 22psi on 5.7 injectors and i can't go as high in RPM's as i would like, i think the injectors are going static, it goes lean. I am also looking to do 7.4 injectors. My plan is to try 7.4 injectors at 15-16 psi, instead of running higher pressure on smaller injectors. I had my 5.7 injectors at 30psi and it seemed fine, but i was worried about reliability. From what I've read, it can actually be harder to tune with higher fuel pressure, or using a vacuum referenced regulator of sorts. I want to avoid that if I can. According to Desktop Dyno, mine is around 320-340hp and 440ft/lbs, or close to that, I can't remember the exact numbers. I modified my regulator to adjust it, it's fairly easy to do. I think the 7.4 injectors are the way to go.

BLG

**Engine07** · 02-04-2015

Thanks a lot. Sounds like we will have almost identical builds lol. I don't have computer dyno just guessing from what I've built in the past with carbs. Thanks for the advice. Looks like I'll be using ported throttle body, adjustable reg, injector spacer, and 7.4 injectors. My thought was originally using a performer rpm intake with adapter but from what I have read there seems to be big controversy over single plane not losing torque at lower rpm with tbi like it does with carb. Any thoughts or suggestions? Looks like fast355 was running a victor jr 2bbl intake with good success on tbi without losing low end torque?

**Fast355** · 02-04-2015

Originally Posted by BLG355

I am currently running 22psi on 5.7 injectors and i can't go as high in RPM's as i would like, i think the injectors are going static, it goes lean. I am also looking to do 7.4 injectors. My plan is to try 7.4 injectors at 15-16 psi, instead of running higher pressure on smaller injectors. I had my 5.7 injectors at 30psi and it seemed fine, but i was worried about reliability. From what I've read, it can actually be harder to tune with higher fuel pressure, or using a vacuum referenced regulator of sorts. I want to avoid that if I can. According to Desktop Dyno, mine is around 320-340hp and 440ft/lbs, or close to that, I can't remember the exact numbers. I modified my regulator to adjust it, it's fairly easy to do. I think the 7.4 injectors are the way to go.

BLG

I have a Marine 502 throttle body that has 61# injectors and a 30 psi regulator. They have a different part number and color code than the 5.7 61# injectors but seemed to not have a problem with the pressure.