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[Eveready]

I would spend a year making sure everything on the truck is up to par. An 88 is a pretty old truck. Would be bad to add performance parts and have the thing start nickel and dimeing you with stuff you should have fixed first. Does EVERYTHING about the drive train work properly? Shocks? tie rod ends, internals.. e.g. HVAC . The point is make sure it is an adequate platform for the goodies. Just my unsolicited two cents worth of opinion. Welcome to the forum.

 

[A-2 ace]

@L29Sub thanks for the advice, I have a hand full of Qjets laying around.. my truck has a full true dual exhaust with no cats, so the truck is on a open loop right now so I'm really leaning on carb side..

@Eveready yeah I'm planning on changing out the steering linkages putting new shocks and tires first.. the truck only has heat no a/c... That's part of the reason the man didn't want the truck anymore...

I just got the truck not to long ago and wanted to make it "mine" by doing a few mods to it.. I figured you guys knowing and having these trucks for awhile could give me some good info on what works for you

 

[Eveready]

Has it never had AC or is it just defunct? I assume its never had it although that is surprising for New Mexico. You are a hardy soul. If it is just not working then that would be the first restoration I would look at!

The only reason I brought any of that up is that I have seen others bolt on expensive performance parts only to discover that the basic platform was worn out or had serious issues. Good luck with your new toy!

 

[A-2 ace]

Yeah it came factory with no a/c...it gets really cold here in the winters, it's only 22degrees out today..but the plans right now are to do a full tune-up on the truck.. I'm really not looking to get a whole lot of power out of this truck just a few bolt on here and there, what I'm really looking into is the carb switch.. just don't know if it's a good idea, I had one guy from work tell me I should just leave it tbi cuz it's better then a carb??? But if my ecm is on a open loop cuz of the cats being deleted wouldn't it be the same mpg?

 

[PlayingWithTBI]

You can still run closed loop with a heated O2 sensor. Your truck only came with one and it goes in the driver's side exhaust manifold. The ECM doesn't care if you have a cat. You can get a 46mm bored Throttle Body that will flow 650 CFM which is plenty for a 350 @ 6,000 RPM. The biggest issue with the TBI small block is it doesn't flow worth ****. The peanut heads and cam are anemic. Since you have dual exhaust you've already cured part of the issue. Then, after you build it up, you'll blow the 700r4, if you have an auto. BTDT.

 

[PlayingWithTBI]

My bad, I just reread your post, you have a 5 speed so, disregard my comment about the trans. Here's a link to the throttle body I mentioned.

https://www.ebay.com/itm/46mm-PORTE...837306?hash=item3d963196ba:g:mpwAAOSw2xRYWVJj

 

[A-2 ace]

Ok cool I will check out the link! I've heard about boring out the manifold but wasn't sure... Some people are trolls and will tell you anything you want to hear for ***** and giggles... So I really do appreciate all the help you guys are giving me..

Also I've heard that the springs on the valve train are weak and are not recommend over 4.5k rpm? How true is this?

 

[Schurkey]

the motor is a 94 gm crate engine

I've heard that the springs on the valve train are weak and are not recommend over 4.5k rpm? How true is this?

I put a "service replacement" crate engine for a '91--'93 LO5 Caprice into my K1500 nearly twenty years ago.

That engine--TBI, crappy swirl-port heads (but unlike the original engine, it came with roller cam and flat-top pistons) drove perfectly on the stock computer.

The valve springs on that engine were the SAME as GM used on the early "300 hp 350 cid" GM Performance Parts crate engine.

Wild guess: The valve springs on all TBI engines are the same. They're suitable for mild performance use, and will permit greater valve openings than the valve guides, seals, and retainers will allow in stock form.

Second Wild Gues: Valve springs on the Vortecs are the same as the ones on the TBIs.

Twenty minutes with a GM parts catalog would tell the tale.

VALVE SPRING PART NUMBER IS 3911068 (SAME SPRING USED WITH THE OLD 300H.P 350 CRATE)

INSTALLED HEIGHT 1.70" PRESSURE @ INSTALLED HEIGHT IS 80 LBS * PRESSURE WITH VALVE OPEN IS 267 LBS.

THESE SPRINGS ARE GOOD FOR .550" LIFT BUT CLEARENCE BETWEEN GUIDE AND RETAINER MUST BE DOUBLE CHECKED BEFORE ATTEMPTING.

 

[PlayingWithTBI]

I've heard about boring out the manifold but wasn't sure

Yes, the manifold bores are 1-11/16" (~43mm) with the 46mm throttle body you should bore it to 48mm

Also I've heard that the springs on the valve train are weak and are not recommend over 4.5k rpm?

It's true, these heads aren't worth keeping. Here's a set of heads that flow better than Vortec and have 2.02"/1.60" valves. They say these are good to 5,000RPM, I've taken them higher though. If you want to go stiffer than .480" lift, you can change the springs.
https://www.summitracing.com/parts/sum-162108/overview/make/chevrolet

 

[A-2 ace]

So on the jegs website it's saying the motor "can" produce 210hp.. that can't be a realistic number with the tbi set up?? So I'm gonna say 180hp???