I am thinking of building up a 350 tbi for my t/a. besides building the engine, which I have built before, what needs to be done? if I keep the tbi system will the computer still work? would I just need to burn a new chip. Also, should I use a holley 670 cfm tbi? Are there any cars I can look to get a 350 out of to build up? I am sorry for the questions I know they are kinda vague and wide open...but I usually build engines for my fathersd 1st gens...not my third gen. Thanks..Also, how much horsepower is possible with a 350 tbi and a not small, but now huge buget? Thanks

 

id stay away from the late 70's v8's beacuse of the machining flaws that some have concerning the starter and lifter bores. The L98's and the vortecs are popular. With a vortec, you could just use the engine as is with maybe a slightly larger cam. Youll probably be able to use the vortec as is since reasonable low milage ones can be had. With the cam id stay away from the high lduration (~212+ or so at the intake)/low LSA (<112) ones and dont use large cc runner heads. Try to pick parts that will compliment the lower revving tbi system. Of coarse, jsut about any 350 block will do, whether its a one peice or a two peice. Its your choice. If your serious about it youll want to make up a new bin for the ecm to get it to work well. Its a really good idea to get over to the DIY-Prom board now and start to familiarize yourself with what youll need to get/what will need to be done. Dont be like me and wait untill your ready to actually burn the prom because there is alot of stuff you need to know ahead of time when getting parts and what not. The earlier you can familiarize yourself with it, the better.

oh, almost forgot: yes you will need the 670. Dont use the stock one because its all kinds of restrictive.

 

What kind of hourse power can I look for If I get a vortec and use the tbi and new cam? I know horsepower varies witheach cam, but what am I basically looking at?

 

I would say get you a full roller 350 vortec and put a mild low end torquer cam in , get the holley 670,headers and full exhuast. You will need a custom chip or you can do what I did and a get a chip out of a cop car caprice with a 350.If I were you I when get one with the egr burned off of it so you can run a better intake like a performer RPM . Remember you have to have a vortec manifold for your vortec heads. With all of that I would say you would push a good 300 hp and a ton of low end torque. Good luck

 

In your profile, your car says its an 88. If this is true. You will have to get a 350 block from a 87-95 Chevy Pickup. Between these years GM changed the mounting holes in the heads for accessory brackets. So, unless you want to waste money getting custom brackets you need to stay in these years.

305vs350tbi Here's the details.

---NEW KNOCK SENSOR for 350 --> 305 wont work correctly which either will kill all your power or not detect knock correctly

---NEW KNOCK MODULE(Also called spark control module)

---ECU chip --> Brian Harris can burn you a generic chip that will work great. (He did for me the first time) He's on this message board somewhere.....he also sells them on E-bay.

---350 TBI off at least a 350 truck, The holley 650 (from what I've heard) is a waste of $$.

***Do the ULTIMATE TBI MODS TO TBI before installation. This mod will probably give you about the same flow as the holley.....and its FREE!!!!!!! (Someone link to it for him plz)

---AFPR --> Adjustible fuel pressure regulator....this part isn't needed. I ran without one for awhile, but it was lean so this will help you get the full potential out of your motor.

If I get a chance, I'll post some picks of some of these parts. Especially the knock module to help eliminate confusion.

THESE are the only real modifications you have to make to allow it to work and live correctly.

 

At least 300hp with about only $2300 total (this includes the price of the block and the $1K that new heads would cost.

 

Rich92RS350 just bought one from http://www.goautocenter.com

He got the 350 TPI with the optional TBI cam. I think he dynoed it before installing and he had around 310 HP and 390 lb/ft. MORE than enough to have fun with. Plus, he gets a warrenty on the motor.

I don't think that a Holley TBI unit would be necessary as someone already stated. If I'm correct, the only difference between the 350 and 305 Throttle Bodies was the size of the injectors and fuel pressure. Just do the Ultimate TBI mod and upgrade your injectors and you should be fine.

-The Gunny

 

You actually dont need the holley but I would reccomend getting it .Does anyone have any proof that the ultimate tbi mods make 670 cfm if not you gonna want the holley.The stock tbi flows like 400 cfm that will totally choke a 300 hp motor .You want the holley , you can find them new on ebay for like $200 sometimes and used for even less.Your gonna want the extra air flow and it comes with 65 lbs injectors which is what you need as well.

 

I understand the holley has the most flow, but what If I use a 454 tb and do the ultimate tbi mods? Would that have more flow? Which would handle more power?

 

I actually dont know much about the 454 tb but It is supposed to flow 670 cfm so if you do the ultimate tbi mods on it you should definetly have more flow . I saw a guy on ebay who was claiming 750 cfm from mods like the ultimate tbi mods he did to a 454 tb but I doubt it actually was flowing that well. But unless you are looking for 400 horses 670 cfm should be plenty of flow for your engine you dont want more air than your engine needs,but I doubt 750 cfm would be to much as long as you have at least 300 hp. Good luck

 

www.sdpc2000.com has a new custom crate motor, 4 bolt main roller block (L31), "906" Vortec heads, and .431/.451 196/206 mild roller cam for $2150. Rated at 330HP, 414ft-lbs with a carb and open headers.