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350 TBI Motor Upgrades

1990k5fan

1990k5fan

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Location
Gilroy, CA
I'm building up my 1990 stock tbi 350.
It already has a hi-flow cat, and tbi-spacer.

Here are my planned mods so far, and remember this has to pass smog in CA. If any of my planned parts are wrong or if you can suggest something better, please do so :] Thanks

Cam and Lifter:http://store.summitracing.com/partdetail.asp?part=EDL%2D2102&autoview=sku

Headers: I don't know what to really look for? There are so many different sizes and I searched on here but still couldn't decide. Any help is greatly appreciated.

Intake: Edlebrock Performer TBI Intake Manifold http://store.summitracing.com/partdetail.asp?autofilter=1∂=EDL%2D3704&N=700+4294908216+4294908215+4294924929+4294840140+4294822100+115&autoview=sku

Heads: Getting a set of older aluminum corvette heads that have been ported and are getting a valve job.

Chip: Getting a custom chip from www.tbichips.com

Electric Fuel Pump: http://store.summitracing.com/partdetail.asp?autofilter=1∂=ACF%2DEP386&N=700+4294908216+4294908215+4294924929+4294840140+4294925239+4294839053+4294836951+115&autoview=sku

Am I missing anything?What horse power and torque should this net me?

Edit: forgot to mention that this is my DD and my weekend warrior. Drive it a couple miles back and forth to school daily. :D
 
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I think you're going to have problems with the heads as far as smog is concerned. Our trucks never came with aluminum heads so if you have some you better have a carb OE number. Kinda hard to have a carb OE number when they aren't aftermarket heads. Just something to think about or ask your local smog trech about before you go spending that money.
 
Do you think the smog people would really notice the different aluminum heads? And if they did what would happen? Would I get a fix it ticket to put the stock ones back on or what?
 
Hate to say this but the cam will never pass smog without time on a dyno.
Headers ? very fewCARB approved headers out there. .. Edelbrock TES and Doug Thorly are Carb approved with numbersthat will pass smog
Old aluiminium L98 heads?? 59 cc chambers= Very high compression ratio. Not sure if the cam you have will work with a 10 to 1 compression ratio. But who knows??? We are just throwingparts togeather with no plan
A stock AC delco fuel pump to feed the combo you want.??? Dont think so.
You need at least a 190 LPH Walbro to feed a performance build 220 lph would be best. all this and TBI ..... Yeah baby! And about a day on the dyno
 
Well I emailed the guy at tbichips and he recommended everything except the heads. I was supposed to buy a set of ported 194 heads from the local engine builder but after testing them, he found out that they were badly cracked.

I'll find out the specifics tomorrow after I check in with the engine builder.

I want to build a 300+ hp / torque motor with good torque down low. I know the limits of the TBI so I'm looking for my best bet at reaching that goal.
 
Ported 193 heads will work with your combo. The l98 vette heads will not.
The 193 heads on your 90 are a good head to work with why dont you just port them?
300 HP out of a stock TBI is hard to reach without getting a bigger TB and injectors. 260-280 hp 330+ lbs torque is a very reachable goal with what you are trying to do.
Thats more than a vortec 350 puts out.
Talk to the guy at TBI chips. ask him about a Comp cam#Xe249H and a set of 1.6 roler lifters. it is a better computer frendly cam than the summit cam, and should be able to pass Ca smog
 
Thunder said:
Ported 193 heads will work with your combo. The l98 vette heads will not.
The 193 heads on your 90 are a good head to work with why dont you just port them?
300 HP out of a stock TBI is hard to reach without getting a bigger TB and injectors. 260-280 hp 330+ lbs torque is a very reachable goal with what you are trying to do.
Thats more than a vortec 350 puts out.
Talk to the guy at TBI chips. ask him about a Comp cam#Xe249H and a set of 1.6 roler lifters. it is a better computer frendly cam than the summit cam, and should be able to pass Ca smog
Click to expand...
Well the reason I was going to go with the vette alum. heads was because the guy got them cheap, and they were already ported and such, so he was going to give me a really good deal. I guess I'll rethink that one.

Is the Comp Cam #XE249H the only you would recommend? Sumitt doesn't have that one. Would I be better off buying one of the ones off sumitt or directly from Comp Cams. Also, for the cam, do I need the kit or just the camshaft from the Comp Cams website? http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=K12-249-4

So with an intake, cam, 1.6 roller lifters, and ported heads, I should make 330 torque easy? What does the 90 350 come with stock for torque? I checked online and could only find the horse power rating.
 
Yeah but I just can't belive the 300 torque. Especially since I dd my truck and it does not feel like it has 300 ft/lbs of torque.
 
1990k5fan said:
Yeah but I just can't belive the 300 torque. Especially since I dd my truck and it does not feel like it has 300 ft/lbs of torque.
Click to expand...
could be quite a few things. along with it weighing in at around 5600lbs and with the aerodynamics of a brick.

btw heres the page you want:

ctv1-74.jpg
 
People hugely underestimate the amount of torque these things put out. Smog restrictions really didn't affect the low end torque the truck engines made, and they only got better with TBI.

That's 300ft/lbs with all accessories on and running, through stock exhaust. IIRC the correction is something like +20% if figuring gross HP/TQ. Of course that's a pretty rough correction number, different components rob different amounts of power.

What gears are you running, along with tires? That's one reason a lot of the trucks feel like dogs, they are saddled with 3.08 gears, and putting larger than stock tires on only makes the performance feel worse.
 
That cam has a really long duration at 0.006 for the amount of 0.050 duration. Edelbrock and Summit cam grinds are old school technology The ramp rates are slow. You will make more HP and Torque with a newer grind like a Lunati Voo Doo or a Comp Extreme. They build more cylinder pressure and have shorter overall durations for the same 0.050 duration.
 
I'm running 4:10 gears with 33's.
I'm looking at getting the Comp Cam suggested earlier in this post and skipping the porting of the heads.

I'll just be getting the Comp Cam, Timing Chain, Roller Rockers 1.6, Valve springs, Intake, Headers and a new fuel pump.
 
How much torque can the stock TBI / injectors take? I know that it is recommended to not go over 300hp but what about torque wise? if it is already at 300, how much would it go up? Also, can anyone recommend a good throttle body to upgrade to along with bigger injectors?
 
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