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emissions removal

87k5350

87k5350

1/2 ton status
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Mar 15, 2009
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Palm city, Fl.
Greetings, anyone see any big isues with what i'm planning?
It's an 87 k5 w/ tbi-350 all the top em stuff is intact down to the ex manafolds. I plan to stay with the tbi but clean it up with removal of the emmissions crap including headers and intake w/ a mild cam the exhaust after the manafolds has been changed with no smog parts before me. I havn't been in the engine yet to see anything yet, but were the 87 350tbi engines a flat tappet motor? Kinda been out of the loop in GM since 76.
 
Other than removing AIR, probably might want to forego the other mods. I don't believe stock TBI heads on these motors can be "woken up" with an intake, as the ports are what restricts flow, so no matter what other parts you change upstream of the intake ports, the heads are going to hold you back unless they are worked on. Exhaust will never hurt, and will be one of the reasons to remove AIR, unless you get headers that have the right AIR ports.

EGR and EVAP hurt nothing, and actually help, so you aren't doing yourself any favor by trying to remove them.

Yes, flat tappet.
 
Almost none. Note that the AIR and PS pumps didn't get a multi-groove belt while the alternator did, before the switch to full serpentine.
 
It's really not all for power (some would be only a bonus) but more to just clean it up a little or simplify it , a litttle less crap+ I was thinking putting the tb on a sq bore intake with an adapter would ensure an evening out of the mix from old injectors might be an improvment. I'm not really use to tbi stuff yet. Doesn't each port & inj feed only one bank period! stock wise?
 
As an experienced third-gen camaro guy, which uses almost the same equipment as TBI trucks, don't take the emissions off. Your prom functions off of many parameters, and taking off the smog pump is going to hinder your ECM, performance, and cause one hell of a headache when you look down and see your service engine light flashing 24/7.

If you really want to do the performance mods, first go to dynamicefi.com . This guy sells a system that allows you to infinitely re-tune your prom (including the removal of such emissions equipment). Obviously, do so with the knowledge of your state's emissions requirements.

Second, the swirl-port iron cylinder heads are feces (to be blunt). YOu can find a good set of iron (or aluminum) Corvette, Camaro or Trans Am heads for cheap. The best ones (from the Gen1 small blocks) are the Corvette L98 heads, casting number 113. Then go with a hi-po TBI intake. Personally, I'd leave the EGR on there. By recirculating Exhaust gas (EGR- Exhaust Gas Recirculation), you are lowering combustion temperatures at a lower engine load. This helps with your low-rpm performance, fuel economy, and engine longevity.
 
Yes, each injector feeds one engine bank (cylinders 1357 on the drivers side and 2468 on teh passenger). But, one injector pulse does not feed all 4 cylinders on one side, it is multiple pulses per rotation. If you ever look at a TBI unit while the engine is running (pull off the air cleaner and the small metal ring at the TBI base), you'll see the injects firing. They fire so quickly that it almost looks like one continuous spray

IF you really want to simplify it all, go carb.
 
TBi is actually very clean up top. Total of like 4 vacuum lines, nothing compared to the 80's carbed stuff. :)
 
its looks as though a guy has to decide wheater he wants performance or fuel mileage with TBI

combing big power and TBI doesnt work, the small add ons here and there, are they really worth it for a full out trail truck...
 
dyeager535 said:
TBi is actually very clean up top. Total of like 4 vacuum lines, nothing compared to the 80's carbed stuff. :)
Click to expand...

VERY TRUE...THAT'S MY NEXT PROJECT: STRAIGHTEN OUT ALL THE VACUUM LINES..HALF OF MINE ARE NOT HOOKED UP AND SOME ARE PLUGGED...I BELIEVE EXPLAINS MY 8 MPGS.:doah:
 
The 80's look was pretty buisy too, as far as the tbi it is pretty clean but I like headers not tubed manafolds, the pumps gotta go too . I'm not driving it daily its a project truck , couplea times a week type thing. My questions were more for how far I could go with out an engine light and loosing power I was a 60's and 70's sb guy. Oh! and can any one tell me anything about these heads (specs) 87 350 ? thanks
 
There are a couple of them that seem to consistently produce power. As with any other engine build, the components need to be matched. Good flowing heads are nothing without a good intake and exhaust, and you can't get the most out of any of them without a custom PROM.

Fuel mileage typically doesn't change if you don't go overboard on the operating RPM of the engine...if you spend most of your time below 4000RPM's, building a motor with power at 5000+ is going to result in poor mileage. More air in equals more fuel used.
 
Say I go with a few mods is there a programer or vender who can take your mod specs and program a chip to your likeing?
 
you can still make decent power with TBI...holley makes a performance 670 cfm unit, and the 454 throttle bodies will bolt right in. 320 crank horses and about 350-400 torque is very plausible
 
Thanks guys, this TBI thing is getting more undestandable by the minute.
The TBI and the necessary component changes, Heads ect as well as the newer tranys are gonna be a fun challange.Glad I came back to GM
 
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