85 K5/Engine build help...

[bigblaza]

Ok, so as stated in the title I have an '85 k5 that I've been building on/off for the last 5 years. I have the body, paint and most of the interior complete or at least where I want it. As it stands here are the mechanical specs on it so far:

-39" trxs tires (20" rims)
-6" suspension(springs) w/ 2" body lift
- 14bFF 4.56 rear w/ 4wheel discs
- NP208
-MSD offroad ignition
- 4bl 650cfm carb (not sure the brand) w. K&N
- Stock SB 350 w/edelbrock ceramic coated headers
-Custom dual exhaust w/ dual flowmasters

Ok so for the final stage of my build Ive gotten my hands on a bored .030 350 that I plan on building into a 383 stroker. I haven't purchased any parts yet but that was part of why I was posting here. I want to run FI from here on out when I actually go to build the last stages of my truck. Alot of people on here have a wealth of knowledge on here and gives great advice, so I would appreciate any help you guys can give me. Here are my questions/concerns:

-Which FI system is best to put in? TPI.TBI,MPFI? (brand or part specific even)
- What engine internals would be best? (Heads Aluminum/iron? size?, Dome/flat top piston?, lifters?, ect..)
-Serpentine or V-belt?

Price is not really a big deal. Im not implying that I am made of money or Im trying to throw money away, but Ive been building this thing for the last 5 years so a few more to save up isn't a big deal. Im not looking to go supercharged or anything like that, just looking for a solid powerplant that is efficient. Its not going to be a daily driver but its not gonna be a rock crawler either, its just gonna be semi-street semi-offroad just for havin fun mostly. Anyone with a little technical know how would be greatly appreciated. Thanks in advance...

 

[Thunder]

I like TBI for trucks so of course I am going to say TBI is the best. It is the system I would use on a 383 if I were building a "Having fun offroad truck".
TBI is cheapest to build. You will need bigger injectors, bigger TB, custom tuned chip for your engine. Edelbrock or Holley intake would be good too. Parts are available everywhere. You can usually pick up a whole system from a wrecking yard cheap. TBI is very dependable and simple for FI. Also is the easiest to install.

TPI is also very good on trucks, Builds very good torque. Parts are available most everywhere. But it is getting harder to get complete TPI from wrecking yards.
It will cost more to build for a 383. TPI is barley adequate for a 350 let alone a 383.
You wil need more air and fuel. 24 LB hr injectors. Bigger intake runners or aftermarket intake and a custom tuned chip will be needed. A little more technical install than TBI but not that hard.

Aftermarket MPFI. Lots of stuff out there Holley, Edelbrock, Accel, plus a bunch of others make Bolt on MPFI systems. Benefits are, most of them are tuneable with a laptop. So you dont have to get chips burned to tune the system. Changes can be easily made for different cams, and other engine mods.
If you were building a high powered street/strip engine the digital MPFI systems are great. But they cost $$$. But for a basic truck engine that wont see the other side of 5K rpm TBI or TPI will do the same thing, make same power/torque, and be far less expensive.

As for heads I would go with Vortec heads they work great on 383s
You can go fancy with ALU heads like AFR or similar but not really needed on a low RPM truck. Iron heads will be fine for your needs.
World Torquers or Dart Iron Eagle heads will also work good. But Vortecs are my 1st choice as long as you dont go with high valve lift.
Pistons Crank ect. Go with a kit that will give you a compression ratio 9 to 9.5 to one so you can easily run on any pump gas. Eagle, SCAT, make complete stroker kits.
Lifters, springs ect. Go with whatever the cam manufacture recommends. Best to get a matched kit for your cam.

I like serpentine belt but you will need to get a serpentine waterpump. Serp pumps are reverse rotation.

 

[bigblaza]

Awesome info. Exactly what I was looking for...

Why is TPI not as good for a 350 and 383? I would think they would be more efficient running 8 injectors vs 2/4. Shows how much I know.

I've checked out jegs.com and ebay for aftermarket MPFI (and TPI, TBI) kits and even the used ones are pricey. So hypotheticaly if you were offered a functional but used, any of the above mentioned systems for say a quarter of there original price which would you choose. Basically Im trying to find out if its kinda "if you can get a super cheap MPFI go for it but if you can't then go for tbi/tpi" ? I dont want to get a system for the simple fact to say I got it. If it has some obvious better qualities then I could see saving up for it or trying to find a good deal.

 

[Thunder]

I never said TPI was not as good for a 350 or 383 as other systems. Just that it will cost more to install and modify one for a 383.
TPI is a very good system.
TPI was orginally designed around the 305 engine. The intake runners are small and the 19 lb hr injectors wont feed a 383 or built 350. If you could find a TPI off a 350 it would work. 350 TPI came with 24LB injectors. But you will still have small intake runners feeding a stroked 350. Great for torque but you will run out of wind around 4600 RPM. But with a mild built 383 you should not see much time over 5000 rpm anyhow. So it should work ok if you keep the build on your 383 fairly mild, and torque. Not high rpm hp is what you are after.
There is an easy fix. A ported base, larger intake runners, and bigger throttle body will get you up to the 400 hp range with 30 lb hr injectors. Plus still make gobs of torque.
Also if you use vortec heads you need a aftermarket TPI to vortec head intake manifold base These come with all the needed mods and larger intake runners for better air flow. Because of the long intake runner length which builds torque not high rpm HP. TPI is an excellent choice for a truck.

As I said in my earlier post I like TBI. It is not better than TPI. But can be built to perform almost the same as TPI for less money.
You can find a donor truck and pull everything off it you need you should be able to get the parts you need for around 200 from a wrecking yard.
Once you get the complete system.
You will need a bigger TB for around 250-300. Bigger injectors will cost around 100.
Chip=$250 or so.
If you use Vortec heads you will need a Vortec to TBI intake manifold they are around 400 including the plumbing for EGR.

As far as aftermarket kits for cheap.... You get what you pay for with EFI. There is a reason someone is selling it. Unless you know the person or the kit I would be wary about buying one.


FYI here is a very good site about TPI http://www.chevythunder.com/
it will help you understand both TPI and TBI.

There is a lot of info in the garage and the injection bords on the TBI swap too.

 

[bigblaza]

I just thought of something else...What if I were to run a stealth-ram or super-ram, or mini-ram...would/could see better results from something like that? I mean changing the base should give better HP and torque right?I mean I know there would have to be some slight modification to the rest of the system but Im just trying to see the possibilities...If I did do that wouldn't I need to either pick up some different heads or have them ported as well, for better/more flow at "higher" RPM??

I've been offered a TPI setup off of a 5.7 Z28 (1987) with a MAF setup for $260. It everything is there runners, TB, 24lb injectors, plenum, ECU (that was burned for 5.7) and all wiring (uncut) I was just wanting to know if this was a good deal and how modifiable this was to maybe get some better performance for without completely getting all new parts.

As I said before I dont have heads, cam, or anything else for that matter. Im just trying to be as informed as I can before I start buying...thanks again.

 

[jt512]

No usefull advice for you, but where in MD are you? Always nice to see "local" K5ers here!

 

[bigblaza]

Im in Southern MD(charles county), by waldorf/La plata, if you know where that is...

What about you?

 

[jt512]

Way up north from you, I live in harford county (north of Bel Air). I know exactly where LaPlata /Waldorf is, been to Budds Creek and Capital Raceway more times then I can remember!

 

[bigblaza]

Way up north from you, I live in harford county (north of Bel Air). I know exactly where LaPlata /Waldorf is, been to Budds Creek and Capital Raceway more times then I can remember!

Wow yeah, you're way the heII up there...Im about 20 min from budds creek.