What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

89 350 TBI Upgrades

mudbuggy

mudbuggy

1/2 ton status
Joined
Jun 10, 2010
Posts
631
Reaction score
1
Location
Indianapolis, Indiana
I have read somewhere, can't remember where, that a stock 350 is capable of about 360 hp in a 'stock' configuration. How is this horsepower increase made and where do I start? More I think about it, I think it was in a Peterson's 4wheel magazine.
 
mudbuggy said:
I have read somewhere, can't remember where, that a stock 350 is capable of about 360 hp in a 'stock' configuration. How is this horsepower increase made and where do I start? More I think about it, I think it was in a Peterson's 4wheel magazine.
Click to expand...

You are not going to get anywhere near 360hp from a stock 350 even with a few external add-ons. HP cost money and the numbers are made with valvetrain and heads.
 
So with bumping up the fuel pressure and the addition of the 'spacer' plate, what are the numbers that I can reasonably expect?
 
Bumping up the Fuel pressure will do no good, unless the engine needs it. The biggest noticeable bang for your buck, would be CFMTech`s TBI spacer, as it has an open area between the throttle bores, so both sides of the manifold can take advantage of both barrels. Stay away from any gimmicks that swirl the air for the intake side, and any mufflers that say Flowmaster for the exhaust side.
 
I just ordered the spacer from them. Hope it helps! It says it adds 15hp!!
$95.30 Delivered.
 
3 huge restrictions for tbi is

complete exaust system motor back. DONT reuse any of it.

stock flat tappet tbi cam is just TINY in its #'s to make any real power.

stock instake is o.k. but not the best.

best thing for you is do a search here for tbi mods.

been covered a bunch in few of the sections we have here not just injection section.

i my self along with others have posted lots of info and links to info.
 
sweetk30 said:
3 huge restrictions for tbi is

complete exaust system motor back. DONT reuse any of it.

stock flat tappet tbi cam is just TINY in its #'s to make any real power.

stock instake is o.k. but not the best.

best thing for you is do a search here for tbi mods.

been covered a bunch in few of the sections we have here not just injection section.

i my self along with others have posted lots of info and links to info.
Click to expand...

30+whp gain...So good it will make you slap your mama!:doah:

http://www.tornadoair.com/buy1/

41ijddey2mL._SS500_.jpg
 
I don't want to do mechanical things to this motor, I have another one in the garage for a replacement for this one that will have the 'better' mechanical advantages to it. I made an order to CFM tech, got a set of injectors, the fuel regulator adjuster kit, guage fitting, guage, the salad bowl thingy, and the supersucker plate. Since I pulled this truck out of the corn field, (sat there for 3 years and I got it for $25.00!) I haven't had to do a pump. I think when the pump goes out I will upgrade to the vortec pump or bigger, (getting ready for the next motor) thinking that I might do the shackle flip at the same time.
I am doing the exhaust with shorty headers (hookers 2466) and 2.5" duals hopfully that will clean up the exhaust side. But I am going to have to fabricate the complete exhaust from the headers back since the headers I got ($50 listed in Jegs for $425) are made for a car. My main PITA is that I need a quiet exhaust for in the morning (don't wake the kids and wife when I leave for the shop) then when I hit the exit to the subdivision, hit the cut out switch and run the (Thrush) glass packs for the cruise in. Granted I'm not sure that everything will work how I plan, but hopefully it will fall together. Biggest bitch right now is waiting for the warmer weather so I can start doing it! Anybody feel like volunteering some time? I got a beer tap in the garage somewhere!
 
Shorty headers are worthless, might as well save your money there...Long tube or nothing! Honestly! Especially since they are for a car, don't even waste your time...
 
shovelbill80 said:
why would you say "worthless"?
Click to expand...

I guess I should correct myself in considering the vehicle they are going on. Shortie headers will benefit you specifically in the ability to run a larger exhaust system because of the shear size of the OEM manifold collector being so small. In newer vehicles, shorties are completely worthless...my mind has been on all the new vehicles/engines the last few years, so I apologize! :)

But in general, shortie headers do not give the exhaust pulses enough time (length in primary) to cool down and smooth out the exhaust pulse before it is introduced to the exhaust gasses from the other cylinders. This causes turbulence and disrupts the ability of the exhaust to flow at it's true potential...that is exactly what tuned length long tube headers do! Long tube headers create a siphoning effect that actually helps the exhaust gases suck out of the cylinder and across the valve, this is what makes long tube headers create more low end torque. This reduces the resistance and backflow force on the piston, the valvetrain, and thus creates more power...
 
I guess I should correct myself in considering the vehicle they are going on. Shortie headers will benefit you specifically in the ability to run a larger exhaust system because of the shear size of the OEM manifold collector being so small. In newer vehicles, shorties are completely worthless...my mind has been on all the new vehicles/engines the last few years, so I apologize! :)
Click to expand...

cool...i myself am learning about the likes and dislikes of "stockish" TBI trucks, i never had a fuelie anything before. some folks agree that a shorty with a 1.5" primary, 2.5" collector in to a 3" single works well ...........newer than '90 and i have no clue. in the past, i liked a single exhaust better than duals.

i understand scavenging, reversion and cam timing. least on Harley motors i do.
 
yes shorty headers arnt the best but anything is better than the stock truck exaust manifolds.

dyno results here for the exaust system before/after http://tbichips.com/blackmagic.htm

and you would be better with 2.5" custom y pipe and 3" single exaust on this rig . tbi seems to like that better. and also be much better for doin the cutout exaust you want. less piping and money.
 
mudbuggy said:
I don't want to do mechanical things to this motor, I have another one in the garage for a replacement for this one that will have the 'better' mechanical advantages to it. I made an order to CFM tech, got a set of injectors, the fuel regulator adjuster kit, guage fitting, guage, the salad bowl thingy, and the supersucker plate. Since I pulled this truck out of the corn field, (sat there for 3 years and I got it for $25.00!) I haven't had to do a pump. I think when the pump goes out I will upgrade to the vortec pump or bigger, (getting ready for the next motor) thinking that I might do the shackle flip at the same time.
I am doing the exhaust with shorty headers (hookers 2466) and 2.5" duals hopfully that will clean up the exhaust side. But I am going to have to fabricate the complete exhaust from the headers back since the headers I got ($50 listed in Jegs for $425) are made for a car. My main PITA is that I need a quiet exhaust for in the morning (don't wake the kids and wife when I leave for the shop) then when I hit the exit to the subdivision, hit the cut out switch and run the (Thrush) glass packs for the cruise in. Granted I'm not sure that everything will work how I plan, but hopefully it will fall together. Biggest bitch right now is waiting for the warmer weather so I can start doing it! Anybody feel like volunteering some time? I got a beer tap in the garage somewhere!
Click to expand...
Whoa...wait a minute....Vortec pump? As in a pump made by the supercharger company, or, a pump for a Vortec truck? If its for a Vortec truck, and you are staying with TBI, don`t do it. Vortec fuel pressure is around 50 psi, compared to the 13 psi that the TBI is designed for.
 
Boy can you guys bust up some plans! lol Glad to have all of you to bounce the ideas off of! Let me guess, your saying is to put the oem pump back in until I have to do the motor, not put an upgraded pump and adjust it down?
 
I'm currently running an intank pump that produces 80 psi and 255 LPH and my regulator is set for 18 psi and I don't have any issues and i've been running it this way since 1/20/2008 when I installed the new engine I built.
 
4X4HIGH said:
I'm currently running an intank pump that produces 80 psi and 255 LPH and my regulator is set for 18 psi and I don't have any issues and i've been running it this way since 1/20/2008 when I installed the new engine I built.
Click to expand...


can you tell us about your engine....or have a link to your build up?
 
shovelbill80 said:
can you tell us about your engine....or have a link to your build up?
Click to expand...

It started life as a 350 and is now bored .030" oversize with a 12cc dish piston and a 65cc AFR head with a squared and zero decked block making the CR 9.489:1. I'm running a XFI comp roller cam with 1.6 Comp cams Magnum roller rockers, a Cloyes hex-a-just timing set with the cam installed at 109* centerline and i'm running a stock intake that was taper bored to accept a 454 TBI unit that is running 98 lb/hr injectors with an 18 psi regulator spring and I modified the stock regulator to be adjustable and have the pressure set at 18 psi.

Anything else you need to know just ask.
 
You must log in or register to reply here.

Latest Posts

Top Bottom